Book of Abstracts

www.cicima.ucr.ac.cr

Organizers:

Sponsors:

INTERNATIONAL INVITED SPEAKERS

DESCRIPTION

SCiMAN2018 is the 13th annual symposium organized by the CICIMA (Materials Science

and Engineering Research Center) of the Universidad de Costa Rica (UCR) and with the

collaboration of different departments of the Universidad Nacional de Costa Rica (UNA)

and the Instituto Tecnológico de Costa Rica (ITCR). It represents an effort to provide to the

scientific and engineering community a space to share results of research obtained of their

annual labor in topics related to the science and engineering of advanced materials,

nanoscience, and nanotechnology. Historically, the attendees are scientists, engineers, and

students belonging to national and international universities and laboratories.

PROGRAM

Hours Monday, 10 December Tuesday, 11 December Wednesday, 12 December

8:00 Registration of participants

8:30 Welcome talks from organizers Registration of participants Registration of participants

Session A: Materials Reviews I Session E: Materials Reviews II Session I: Materials Reviews III

9:00 A1: Ullrich Steiner (Adolphe Merkle Inst., Fribourg, Switzerland): Soft Optics from the micron to the nanoscale: bioinspired photonics and optical metamaterials based on polymer self-assembly

E1: Gustau Catalán (ICREA/ICN2, Catalonia, Spain): Flexoelectricity: bending-induced polarization, from bytes to bones

I1: Harry Westfahl Jr. (LNLS, CNPEM, Campinhas, Brazil): The potentialities of Sirius, the new Brazilian Synchrotron Light Source, for the research in advanced materials and nanotechnology

9:50 Coffee Break

Session B: Spectroscopy and Optics Devices Session F: Electric, Magnetic and Mechanical Properties I Session J: Materials Applications

10:20 B1: Mónica Morales (Inst. for Nanotechnology, Enschede, The Netherlands): Advances in the development of transparent conductive oxides: from defect passivation to application in optoelectronic devices

F1: Manuel Vázquez (Instituto de Ciencia de Materiales de Madrid, CSIC, Spain): Magnetic nanowires: from synthesis and magnetic characterization to technological applications

J1: Ignacio Figueroa (Inst. de Invest. en Materiales, UNAM, México): CO2 capture capacity of open-cell Mg foams and the effect of lithium impregnation

11:10 B2: Esteban Bermúdez (Adolphe Merkle Institute, Fribourg, Switzerland): Self-rolled multilayered metamaterials

F2: Fabián Vásquez (CICIMA, UCR): Piezoelectric mimicry of flexoelectricity

J2: María G. Fernández (CELEQ, UCR): Erythrite as water oxidation catalyst: Role of the buffer in the amorphization kinetics

11:30 B3: Daniel Azofeifa (CICIMA, UCR): Change in the dielectric function of Niobium thin films as function of Hydrogen absorption

F3: Kumara Cordero (ICN2/Univ. A. Barcelona, Catalonia, Spain): Effect of flexoelectricity on the nanomechanical properties of ferroelectrics

J3: Sergio A. Paniagua (Lanotec, Costa Rica): Generation of nanotopographic bactericidal surfaces

11:50 B4: Erick Castellón (Esc. Química & CICIMA, UCR): Electrooptical devices based on liquid crystals dispersions in hybrid organic-inorganic mixed oxides of silicon and vanadium synthesized by the sol-gel method

F4: Federico Gramazio (ICN2/Univ. A. Barcelona, Catalonia, Spain): Determination of nanomechanical properties of surfaces by atomic force microscopy using higher harmonics

J4: Laria Rodriguez (Esc. Cien. e Ing. de Mat., ITCR): Characterization of Velvet worm (Onychophora: Peripatidae) secretions by Atomic Force Microscopy (AFM) and Dynamic Light Scattering (DLS) for eventual replacement of synthetic materials

12:10 Lunch Break Closing Remarks and End of SCiMAN2018

Session C: Materials Characterizations Session G: Electric, Magnetic and Mechanical Properties II

13:40 C1: María R. Calvo (CIC, nanoGUNE, Spain): Probing Edge states in two-dimensional topological insulators

G1: Carlos Sabater (Weizmann Inst. Science, Israel): Electronic transport in a single chiral molecule, towards to control spin thermopower by magnetic field or temperature

14:30 C2: Jorge M. Cubero (CIEMTEC, ITCR): Advanced nanostructured materials by severe plastic deformation with multifunctional applications

G2: Charles D. Amos (Univ. Texas at Austin, USA): Effect of chemical treatment on the surface structure of Li1-x[Mn2]O4

14:50 C3: Elena R. Ulate (CIEMTEC, ITCR): Hydrogenation properties and phase transformation of a complex hydrogen storage TiFe-based alloy

G3: Roy Zamora (Esc. Química, ITCR): Mechanical and electrical properties of nanostructured systems based on poly (3,4-ethylenedioxythiophene) (PEDOT) aerogels of starch/κ-carrageenan for electrochemical applications

15:10 C4: Raquel Ramírez (CICANUM, UCR): Optimization of the low-cost manufacturing process of Cu masters for the soft lithography of microfluidic devices

G4: Esteban Rojas (Esc. Química/CICIMA, UCR): Model complexes of amorphous cobalt based water oxidation catalysts: evidence of the role of the anion in the structure and redox properties

15:30 Coffee Break (𝝅-hour)

Session D: Materials Sciences Session H: Bioapplications

16:00 D1: Victoria Quirós (CICIMA, UCR): Large valleys on a bendable bottom-electrode do not change the charge transport through self-assembled monolayers

H1: Marcela Hernández (CICIMA, UCR): Determination, of the presence of a birefringent organic compound in the elytra of beetles C. optima, using infrared spectroscopies

16:20 D2: Yoselin Rojas (CICIMA, UCR): Study of oxide bands in p-type nanostructured silicon layers

H2: Karla Cordero (CELEQ, UCR & Dept. Física, UNA): Graphene-based lab-on-chip sensors for the detection and characterization of C. difficile

16:40 D3: Sofía Chacón (Dept. Física, UNA): Electronic properties analysis of materials at the nanoscale by a homemade scanning tunneling microscope at ambient conditions

H3: Claudia Villarreal (Esc. Cienc. e Ing. de Mat., ITCR): Biophotovoltaic system built from renewable carbon: integration of graphene hybrids and the phototrophic protein bacteriorhodopsin

17:00 D4: Sergio A. Méndez (Esc. Geología, UCR): An estimation of the volatile budget on tephras from Turrialba volcano using Raman spectroscopy

H4: Priscila Hernández (Esc. Cienc. e Ing. de Mat., ITCR): Electrochemical characterization of poly(3,4-ethylene-dioxythiophene)/κ-carrageenan as a biocompatible conductive coat for biologic applications

17:20 End of Talks and Reception End of Talks and Poster Session P

19:00

Poster Session P (Tuesday 11, 17:20 – 19:00 hrs)

P01 Eric G. Romero (Esc. Quím., ITCR): Stability and orientation of organic anions on polypyrrole surfaces by molecular dynamics simulation

P02 Fernando Alvarado (CIEMTEC, ITCR): Study of the thermochromic behavior on Polymethylmethacrylate-Vanadium Oxide matrices for thermochromic windows applications

P03 Álvaro Urrutia (Esc. Cienc. e Ing. Mat., ITCR): Electrophoretic deposition of crystalline nanocellulose based monolayer coatings and composite chitosan/bioglass-alginate/nanocrystalline cellulose multilayer coatings

P04 María C. Monge (Esc. Cienc. e Ing. Mat., ITCR): In-situ calcium phosphate synthesis on biomedical grade stainless steel AISI 316L via electrochemical deposition: particles development and degradation control

P05 Allison Gómez (CEQIATEC, ITCR): Electrochemical flow detection sensor for determination of mancozeb pesticide in water based on Poly (3, 4-ethylenedioxythiophene) (PEDOT) with carbon nanotubes and gold nanoparticles

P06 Karla Ramírez (Esc. Biol., ITCR): Acetylcholinesterase immobilization into a PVA/PVA-SbQ matrix on microplates for high-throughput screening of reversible and irreversible inhibitors

P07 Alejandro Martínez (CICANUM, UCR): Electrode Nanogap-Enabled and Dielectrophoretically Assisted Electrical Auto-Correlation Spectroscopy of Low-Copy Number of Proteins

P08 Alexander Campos (CIEMTEC, ITCR): Development of a computational model for high-pressure torsion optimization

P09 María G. Campos (Esc. Física & CICIMA, UCR): Electronic and optical properties of tetragonal germanium dioxide using quantum espresso suit

P10 Gerardo Valladares (Esc. Cienc. e Ing. Mat., ITCR): Design and simulation of flexible and interdigitated thin-film electrodes for impedance spectroscopy

P11 Luis Ramírez (Adolphe Merkle Inst., Switzerland & CICIMA, UCR): Fabrication of rolled-up metal-dielectric multilayers

P12 Isaac Villalobos (Esc. Física & CICIMA, UCR): A study of electric properties in Graphene and Borophene β12 nanoribbons

P13 Francisco Rodríguez (Esc. Cienc. e Ing. Mat., ITCR): Electromagnetic interference shielding by the use of open-cell aluminum foams

P14 Anyie Atencio (CELEQ & CICIMA, UCR): Solid electrolyte POM-PVA in aluminum-air batteries

P15 Mildred Chaves (CIEMTEC, ITCR): Characterization of a 10-ton High-Pressure Torsion equipment to generate phase transformations in commercially pure titanium

P16 Jeimmy González (CIEMTEC, ITCR): Aging behavior and microstructure of pure Ti and Ti-6Al-7Nb processed by High-Pressure Torsion

P17 Jacqueline Hidalgo (CIEMTEC, ITCR): Photocatalytic activity of yellow and black TiO2-ZnO nanocomposite produced by high-pressure torsion straining

P18 Juan C. Rodríguez (Esc. Física & Esc. Cienc. e Ing. Mat., ITCR): Morphological image processing of nanoparticles’ TEM micrographs

P19 Carolina Haug (CICIMA & Esc. Ing. Química, UCR): Study of modified phase change materials with hydrated particles for electronic applications

P20 María Hernández (CICIMA, UCR): Study of the evolution of oxidation in porous silicon surfaces by infrared spectroscopy and contact angle

P21 Deyvis Alvarado (Esc. Física & Esc. Cienc. e Ing. Mat., ITCR): Synthesis and characterization of silver nanoparticles for analysis of biological materials by SERS

P22 Arianna Quesada (Es. Física, UCR & Lanotec, Costa Rica): Facile synthesis of fluorescent graphene quantum dots and its application as a bio-imaging agent

P23 Mauro Víquez (Ing. Mecatrónica, ITCR): Theoretical study of electrical signals for the stimulation of biological tissues

P24 Esteban Rojas (Lanotec, Costa Rica & Esc. Quím., UCR): Generation of potential bactericidal surfaces from aluminum via anodization

P25 Juan P. Villalobos (Esc. Ing. Quím. & CICANUM, UCR): Fabrication of microfluidic devices for the electrokinetic manipulation of pathogenic samples

P26 Galia Moreno (Lanotec, CR): Extraction and characterization of nanocellulose obtained from agro-industrial wastes produced in Costa Rica

P27 Esteban Solís (Esc. Ing. Civ. & Lanamme, UCR & Lanotec, CR): Effect of the addition of nanocellulose obtained from the residue of pineapple leaves in cementitious mixtures of hydraulic mortar

P28 Carlos Villalobos (Lanotec, CR & Esc. Ing. Mecatrónica, U. Invenio & Museo Nacional CR): Restoring and conservation of Costa Rican cultural patrimony through photogrammetry and additive manufacturing technologies

P29 Melissa D. Barrantes (Esc. Quím. & CICIMA, UCR): First multispectral images in “La Poesía” and “La Danza”, paintings of Vespasiano Bignami at National Theater of Costa Rica

P30 José R. Arce (CICIMA, UCR & Argonne National Lab., USA): Theory of Random Electric Field Instabilities in Relaxor Ferroelectrics

A1

SCiMAN2018 PLENARY

Soft Optics from the micron to the nanoscale: bioinspired photonics and

optical metamaterials based on polymer self-assembly

Ullrich Steiner

Adolphe Merkle Institute, Chemin des Verdiers 4, 1700 Fribourg, Switzerland

Structural colour in animals had evolved 500 million years ago, and despite intense interest for over 100

years, its understanding is incomplete. Highly ordered Photonic crystals are well understood, as is the

diffusion of light within a disordered scattering material, but nature typically bridges these two regimes by

an interplay of order and disorder, the optical response of which is not understood. This presentation gives

an overview of structural colour, ranging from highly ordered to disordered, and illuminates several

interesting strategies to create strong optical responses, despite being made from relatively low-refractive

index materials. It will also lay out the challenges ahead in this field of research.

The second part of the presentation discusses recent efforts in creating materials with unusual optical

properties that are not found in nature. These so-called optical metamaterials are made of sub-100 nm

plasmonic lattices. Rather than the non-resonant propagation of light though dielectric materials, incoming

light excites plasmon-polariton modes that propagate across the lattice and couple out as light on the other

side. By tuning the lattice geometry and topology, is it possible to achieve optical effects that cannot be

attained in dielectric materials, such as a negative refractive index. Here, we have employed the self-

assembly of block copolymers, which defines the size and symmetry of the lattice. The replication of this

lattice into gold or silver results in optical metamaterials. The presentation will discuss recent progress

towards negative refractive index materials by this approach.

B1

SCiMAN2018 INVITED

Advances in the development of transparent conductive oxides: from defect

passivation to application in optoelectronic devices

Esteban Rucavado1, Yury Smirnov2, Christophe Ballif 1, Monica Morales-Masis2

1Ecole Polytechnique Fédérale de Lausanne (EPFL), Neuchâtel, Switzerland

2MESA+ Institute for Nanotechnology. University of Twente. Enschede, The Netherlands

In this presentation we discuss relevant transparent conductive oxide (TCO) electrodes developed in recent

years, their properties, fabrication and their potential for application in distinct optoelectronic devices. We

specifically review the requirements that the TCOs should have to enable higher efficiencies in different

types of solar cells, namely lateral conductivity, carrier selectivity and broadband transparency. With a focus

on indium-free TCOs, we furthermore discuss advances in the understanding of the interrelation between

film microstructure, defects and carrier transport properties of tin-based TCOs such as tin oxide (SnO2), zinc

tin oxide (Zn-Sn-O) and barium stannate (BaSnO3) and proposed design strategies to improve their

optoelectronic properties. Finally, we discuss the current challenges and future directions for the

development of high-performance functional transparent electrodes, from fully inorganic to hybrid thin film

materials.

B2

SCiMAN2018 ORAL

Self-rolled multilayered metamaterials

Esteban Bermúdez-Ureña1, Luis Ramirez-Ramirez1,2 and Ullrich Steiner1

1Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg,

Switzerland 2Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica,

San José, Costa Rica 11501

Over the past decade, multilayered metamaterials have received increasing attention in the photonics

community. Two of the most common examples involve either alternating metal-dielectric films, along with

the nanostructures built from them (e.g. hyperbolic metamaterials), or the stacking of photonic/plasmonic

nanoparticle arrays (multi-layer metasurfaces). In general, the final structures have relied on multiple

deposition and/or patterning steps in order to build the multilayered devices, which can be costly and time-

consuming.

On the other hand, since the introduction of the thin film self-rolling technology, and further works

expanding the materials compatible with the technique, a variety of novel on-chip devices have been

demonstrated. The method exploits a stress driven self-rolling mechanism of a thin film when selectively

released from an underlying substrate. The result of this self-assembly is a microtubular structure with

multilayered surfaces. We exploit this technique as an alternative and powerful approach to enable on-chip

multi-layer metamaterials.

Here, we present two demonstrations of this method. First, we report helicoidally stacked plasmonic

nanoparticle arrays and show results of their selective response to circularly polarized light. In a second

approach, we fabricate rolled-up microtubes with metal-dielectric multilayers and use a focused ion beam

to transfer nanohole arrays onto their surface, in order to study the optical response of these multilayered

metamaterials.

These devices could be implemented as on-chip filters or sensors, and furthermore are compatible with

microfluidic platforms due to their tubular structure. The method in general nonetheless should be

compatible with the inclusion of dielectric structures, quantum emitters and 2D materials among others in

order to build hybrid multilayered metamaterials.

B3

SCiMAN2018 ORAL

Change in the dielectric function of Niobium thin films as function of

Hydrogen absorption

Daniel E. Azofeifa, William E. Vargas, Neville Clark, Hugo Solís and Federico Muñoz-Rojas

Escuela de Física and Centro de Investigación en Ciencia e Ingeniería de Materiales,

Universidad de Costa Rica 11501-2060, San José, Costa Rica

Niobium absorbs hydrogen forming various solid solutions and their properties have been the subject of

extensive studies. In this work, we present the change of the dielectric function of Nb extracted by a Spectral

Projected Gradient Method (SPGM) from optical transmission measurements as a function of hydrogen

concentration. Thin Nb films of 30 and 40 nm, with a Pd overcoat of 6 nm, are prepared in a high vacuum

system on quartz substrates. In situ, they are exposed to hydrogen atmosphere slowly increasing the pressure

up to 1 bar. Electrical resistance and optical transmission (250 to 1050 nm) are measured as hydrogen

pressure is increased. The hydrogen concentration is determined by means of a quartz crystal microbalance.

The electrical resistivity change confirms the hydrogen absorption and the formation of the and -phase.

The dielectric function spectra, found by de SPGM for several hydrogen concentrations, shows, a

displacement of a one of the absorption peaks toward a smaller energies as hydrogen is absorbed. These

results are compared with those from our own DFT calculations of Nb, NbH and HbH2.

B4

SCiMAN2018 ORAL

Electrooptical devices based on liquid crystals dispersions in hybrid organic-

inorganic mixed oxides of silicon and vanadium synthesized by the sol-gel

method

José F. Cascante 1, Erick Castellón 1,2

1Escuela de Química, Universidad de Costa Rica, Costa Rica

2 Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica,

Costa Rica

Liquid crystals (LC) are intermediate mesophases between solids and liquids that have solid-like

molecular organization and liquid-like fluidity. Due to its molecular order, LC are birefringent materials,

exhibiting two refractive indexes: ordinary (no) and extraordinary (ne). Those special combination of

physical properties are exploited for the assembly of electro-optical devices based on LC dispersions, in

which, the liquid-crystalline material is encapsulated as microdrops dispersed in a matrix. The differences

between the refractive indexes of LC and matrix produce a highly scattering state in the composite

material (opaque state of the device). In the LC dispersion devices, the dispersion constitutes a thin film

deposited between transparent conductive substrates, which permit the application of electric field across

the dispersion, allowing the re-orientation of the encapsulated LC, and hence achieving the electrical

modification of the LC refractive index along the field direction. If the encapsulating matrix has a

refractive index that matches that of the electrically re-oriented LC, the light scattering diminishes,

producing a transparent state of the device. In the present work, we used the 4-n-pentyl-4’-cyanobiphenyl

(5CB) LC, which has positive dielectric anisotropy and birefringence (no=1.52, ne=1.70 at 589 nm). We

applied a sol-gel technique to synthetize matrix materials based on hybrid organic-inorganic mixed oxides

of silicon and vanadium (silica-vanadia), with different molar proportions of V/(Si + V). That allowed us

to modify the refractive index of the encapsulating matrices in the range of 1.45 – 1.60, enabling the

specific tailoring of the refractive index to obtain a matrix material that produced LC dispersion devices

with highly opaque (off) state and highly transparent (on) state.

Figure 1. Electrooptical device based on LCs dispersed in hybrid silica-vanadia.

C1

SCiMAN2018 INVITED

Probing edge states in two-dimensional topological insulators

M. Reyes Calvo

CIC nanoGUNE, San Sebastián, Spain

Ikerbasque, Basque Foundation for Science, Bilbao, Spain

For the last 50 years, condensed matter scientists have developed a new classification of materials in terms

of the mathematical properties of their electronic wavefunctions by focusing on their symmetries and

topology. This topological classification of matter, separates materials into trivial and topological (i. e.

non-trivial) phases, with the later often presenting surprising properties when compared to their trivial

counterparts.

Insulators, defined as materials with a gapped bulk band structure, are good examples of the above.

Insulators are often identified for their poor electrical conduction properties, but that is, however, only the

case of trivial insulators, and those belonging to the non-trivial classes can indeed be good conductors.

This scenario was first realized in the Quantum Hall regime in the 1980s. When a 2D electron gas (2DEG)

is subject to a high magnetic field, the bulk becomes insulating but edges remain conductive, and this

conductance is quantized. The experimental realization of a non-trivial insulator in the absence of external

magnetic field did not happen until 2005, in materials with strong spin-orbit coupling interaction and

inverted band structure, namely in HgTe quantum wells. Materials presenting this behavior are referred to

as topological insulators (TIs) (regarding their non-trivial topological electronic structure) and the

conductive edge states often referred to as Quantum Spin Hall (QSH) edge states.

In the model QSH states, spin and linear momentum are locked and thus scattering is forbidden, in other

words conduction is protected against backscattering by time reversal symmetry. The application of a

magnetic field should lift this protection and, above a certain critical field, edge conduction fully

disappears. In real 2D-TI materials, such as inverted HgTe quantum wells, this picture seems to be more

complex and scattering occurs over long enough distances, while complete removal of edge conduction

has not yet been directly shown.

In this talk, I will first introduce the context for topological insulators and their applications, as well as

their predicted properties and the challenges found in their experimental realization. Finally, I will focus

on my work, where I use novel probe techniques to tackle some of the above challenges for HgTe

quantum wells, in particular Scanning Gate Microscopy measurements to identify the microscopic origin

of scattering in the QSH edge states, Microwave Impedance Microscopy to reveal edge conduction at high

magnetic fields, and lateral heterojunctions to probe the properties of edge states at moderate applied

fields.

C2

SCiMAN2018 ORAL

Advanced nanostructured materials by severe plastic deformation with

multifunctional applications

Jorge M. Cubero-Sesin1, Joaquín E. González-Hernandez1, Jacqueline Hidalgo Jiménez1, Jeremy

Barrantes-Rodríguez1, Jeimmy González-Masís1, Fernando A. Dittel-Meza1, Alexánder Campos-

Quirós1, Mauricio Castro1, Mildred Chaves1, Elena R. Ulate-Kolitsky1, María Badilla-Sanchez1,

Jacques Huot2, Kaveh Edalati3,4 and Zenji Horita3,4

1Centro de Investigación y Extensión en Materiales (CIEMTEC), Escuela de Ciencia e Ingeniería

de los Materiales, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica 2Hydrogen Research Institute, Université du Québec à Trois-Rivières, 3351 des Forges, Trois-

Rivières, Québec G9A 5H7, Canada

3Department of Materials Science and Engineering, Kyushu University, Fukuoka 819-0395,

Japan 4International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University,

Fukuoka 819-0395, Japan

The production of nanostructured materials by severe plastic deformation (SPD) provides substantial

improvements in various properties of traditional materials. Research shows that the grain size is a key

factor of the microstructure in polycrystalline materials, which modifies not only the physical behavior, but

other functional properties such as biocompatibility, superplasticity, storage of hydrogen, photocatalytic

capacity and electrical conductivity. In this talk, results of nanostructured materials by SPD developed by

our group are shown for biomedical alloys, oxides and intermetallics for production and storage of hydrogen

and light metals with high strength and high electrical conductivity. Since novel structures resulting from

deformation and phase transformation are possible, SPD provides a research field of great potential. Recent

developments in tooling and equipment for production, characterization and evaluation of such materials in

Costa Rica, with international collaborators are shown.

C3

SCiMAN2018 ORAL

Hydrogenation properties and phase transformation of a complex hydrogen

storage TiFe-based alloy

Elena R. Ulate-Kolitsky1, Alexánder Campos-Quirós1, Lv Peng2, Jorge M. Cubero-Sesin1,

Jacques Huot2

1Centro de Investigación y Extensión en Materiales (CIEMTEC), Escuela de Ciencia e Ingeniería

de los Materiales, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica 2Hydrogen Research Institute, Université du Québec à Trois-Rivières, 3351 des Forges, Trois-

Rivières, Québec G9A 5H7, Canada

The improvement of first hydrogenation kinetics is one of the main focuses when studying TiFe hydrides.

Doping with transitional metals and rare-earth metals has proven to be a good option to improve this

property. Hydrogenation properties where measured with a Sievert`s type apparatus. The alloy

Fe37Ti44Zr9V10 reached an outstanding capacity of 2.3 wt.% at room temperature (RT),1.5 times the

capacity of TiFe. However, the hydride wasn`t able to desorb at RT. The parameters where modified

increasing the desorption temperature to 200°C. The hydride partially released hydrogen ~ 0.4 wt.%. X-Ray

diffraction (XRD) was performed in order to determine what phases where present in the system different

conditions were analyzed. The conditions studied where i) As-cast, ii) Fully activated and iii) Desorbed at

200°C. The XRD results showed some stable hydrides were formed during activation, these continued to be

identified after the sample was desorbed at 200°C. Rietveld refinement was performed to measure the

percentage of each phase in the system. Indexation allowed for a better understanding of the alloy and to

conclude that for this specific alloy the issues that occurred during desorption were due to the main phase.

C4 SCiMAN2018 ORAL

Optimization of the low-cost manufacturing process of Cu masters for the soft

lithography of microfluidic devices

Christopher Espinoza-Araya1, Raquel Ramírez-Carranza2,3, Alejandro Martínez-Brenes2,4, Juan

Pablo Villalobos-Madrigal2,5, Katherine Acuña-Umaña2,3, Caterina Guzmán-Verri6, Leonardo

Lesser-Rojas2,3, Giovanni Sáenz-Arce1

¹ Departamento de Física, Universidad Nacional de Costa Rica, Costa Rica.

² Laboratorio de Nano Bio Sistemas, Centro de Investigación en Ciencias Atómicas y

Moleculares, Universidad de Costa Rica, Costa Rica

³ Escuela de Física, Universidad de Costa Rica, Costa Rica

⁴Escuela de Ciencia e Ingeniería de los Materiales, Instituto Tecnológico de Costa Rica, Costa

Rica

⁵Escuela de Ingeniería Química, Universidad de Costa Rica, Costa Rica 6Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria,

Universidad Nacional, Costa Rica

The present work demonstrates the optimization process that has been carried out in low cost microfluidic

devices with micrometric constrictions, which are used in the study of the electrokinetic response of

several species of pathogens. The optimization focused on the repeatability of the manufacture of the Cu

master, which was previously a random process due to the lack of adequate parameters. First, the design

of the microchannel was modified on a CAD platform, which allowed to properly establish a good

resolution of the constrictions, in addition to the repeatability when printing on satin paper of 200 g/m²

with a laser printer. Next, experiments were carried out to determine the etching rate of the etching

solution at different dilution ratios. The results of these tests established the proportion of water-acid

which were suitable to achieve the etching of smaller constrictions down to 20μm, which are comparable

to those obtained using standard photolithography. Our optimized process lays out the foundation for the

repeatable low-cost fabrication of constriction-based microfluidic devices.

D1

SCiMAN2018 ORAL

Large valleys on a bendable bottom-electrode do not change the charge

transport through self-assembled monolayers

Yuan Li,1 George M. Whitesides1,2, Victoria Quirós3

1Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, MA

02138 2Kavli Institute for Bionano Science & Technology, School of Engineering and Applied

Sciences, Harvard University, 29 Oxford Street, MA 02138 3Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica,

11501 San José, Costa Rica

The drive toward further miniaturization of silicon-based electronics and temperature-independent

alternatives has led to efforts to build electronic devices with organic molecular-scale components. Large

area molecular junctions, usually in the form of self-assembled monolayers (SAMs), also represent the

ultimate improvement of existing flexible devices based on organic materials. Nevertheless, the reliability

of the electronic characteristics of flexible molecular-scale devices hasn’t been well-studied for the simplest

configuration: organic molecules sandwiched between conducting electrodes. Therefore, the aim of this

project is to study the rate of tunneling through an alkanethiol monolayer as a function of the bending angle

of the flexible bottom-electrode.

We have measured tunneling current densities (J) of molecular junctions formed on a flat and a bent bottom-

electrode with different angles of curvature (α). The junctions comprise (i) a gold flexible electrode on a

polyimide substrate, (ii) a SAM of decanethiol, and (iii) a top-electrode composed of a drop of liquid eutectic

GaIn alloy (EGaIn) with a surface film made of predominantly Ga2O3. Our results show that the magnitude

of J doesn’t change with the bending of the electrode, even when large and deep valleys form in its surface

when α > 150°. This proofs that flexible SAM-based junctions, built with EGaIn top-electrodes, have robust

electronic characteristics, indifferently of the topographical changes that the flexible bottom-electrodes

present because of their bending.

Figure 1. Current density measurements as a function of the bending angle for -0.5 V

D2

SCiMAN2018 ORAL

Study of oxide bands in p-type nanostructured silicon layers

Arturo Ramírez-Porras1,2, Yoselin Rojas-Fernández1,3, María J. Hernández-López2

1Centro de Investigación en Ciencia e Ingeniería de Materiales (CICIMA), Universidad de Costa

Rica, San José, Costa Rica 2Escuela de Física, Universidad de Costa Rica, San José, Costa Rica

3Escuela de Ingeniería Química, Universidad de Costa Rica, San José, Costa Rica

The interest in developing fast and reliable chemical and biochemical sensors in an inexpensive way is

something that has attracted a lot of efforts in the last decades [1]. One of the potential material candidates

is electrochemically treated silicon to form porous silicon (PSi). This treatment generates silicon

nanostructures within the porous matrix [2]. The large area to volume ratio is especially interesting for

sensing applications. The main drawback of this material is the fast oxidation that impedes the correct device

detecting capability.

This work is devoted to the study of the oxidation dynamics in PSi. Impedance Spectroscopy (IS) technique

was applied on nanocrystalline silicon (NCSi) samples after submitting those surfaces to distinct phases of

oxidation. Oxide phases were analyzed by Attenuated Total Reflectance in Fourier Transformed Infrared

Spectroscopy (ATR-FTIR) and sessile drop Contact Angle (CA) technique. Nyquist plots were produced

and studied by fitting the curves to a model containing a network of passive circuit elements. Results indicate

a correlation between oxidation evolution (obtained from ATR and CA data) and the equivalent elements

extracted from the impedance model, indicating a change in the surface chemistry of the semiconductor

surface. This change is attributed to the presence of Si-O bonds that replace the Si-H bonds in the original

surface state.

Fig. 1: Schematic cross section of

samples prepared for IS measurements.

Fig. 2: Typical IS spectrograms showing an evolution in the

dynamics of the system, from lower oxidation (smaller

curves), to higher oxidation (larger curves).

References

[1] F. A. Harraz, Sens. Actuators B 202, 897 – 912 (2014).

[2] A. Ramírez-Porras, O. García, C. Vargas, A. Corrales, and J. D. Solís, Appl. Surf. Sci. 347, 471 – 474

(2015).

D3

SCiMAN2018 ORAL

Electronic properties analysis of materials at the nanoscale by a homemade

scanning tunneling microscope at ambient conditions

Sofía Chacón-Vargas1, L. Delgado-Jiménez1, T. Ramírez-Cortés1, Alvaro Vega-Hidalgo1, C.

Sabater-Piqueres2,3 4, Giovanni Sáenz-Arce1

1Laboratorio de Materiales Industriales (LAMI), Departamento de Física, Universidad Nacional,

40101, Heredia, Costa Rica. 2Faculty of Science, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg

2, 2333CA Leiden, The Netherlands 3Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovot, Israel

4Departamento de Física Aplicada, Universidad de Alicante, Campus San Vicente del Rasspeig,

E-03690, Alicante, Spain

The scanning tunneling microscope (STM) has been and continues to be a very important tool for the

analysis of conductive materials at the nanoscale, with this tool it is possible to generate topographic images

at constant current and constant height in nanometric scale and make tunnel spectroscopy in tha specific

point measuring the tunnel current as a function of the applied voltage between tip to sample in a specific

point. Through this, gold and its crystalline construction (111) have been studied, as well as the highly

oriented pyrolytic graphite (HOPG) obtaining atomic resolution images which makes possible the analysis

of the bond length between its atoms, this in order to calibrate the STM [1]. In this present work it was study

the topography and electronic properties of different transparent conductive oxides (TCOs), Indium Tin

Oxide (ITO) and Fluorine Doped Tin oxide (FTO), and also have been analyzed semiconductors for solar

cell applications. For the FTO deposited cadmium sulfide on FTO (CdS / FTO) and the cadmium telluride

deposited on CdS / FTO (CdTe / CdS/ FTO). It should be noted that all measurements were possible at

ambient conditions, obtaining results comparing with the literature [2].

[1] Delgado-Jiménez, L., Chacón-Vargas, S., Sabater-Piqueres, C., & Sáenz-Arce, G. Uniciencia, 33

(2019). 30-42.

[2] F. Matino, L. Persano, V. Arima, D. Pisignano, R. I. R. Blyth, R. Cingolani, and Ross Rinaldi. PRB 72

(2005) 085437.

D4 SCiMAN2018 ORAL

An estimation of the volatile budget on tephras from Turrialba volcano using

Raman spectroscopy

Sergio A. Méndez Rojas1, Oscar H. Lücke Castro1, Pilar Madrigal Quesada1,2

1Escuela Centroamericana de Geología, Facultad de Ciencias, Universidad de Costa Rica, San

José, Costa Rica 11501 2Centro de Investigación en Ciencias Geológicas, Universidad de Costa Rica, San José, Costa

Rica 11501

The fluid inclusions trapped in ashes from volcanos in a subduction zone context, record the volatile content

from the source and can be used to estimate the volatile budget of magma. Olivines and pyroxenes are the

first minerals that crystalize from a parental magma, therefore they reflect a more reliable record of the

composition of the gaseous phase of the source. Since 2015 to the present, the eruptive activity of the

Turrialba volcano has shown an evolution into a more juvenile and mafic composition of tephras, suggesting

in this manner that the volatile content may have also varied. This work in progress aims to evaluate the

variability in the composition of the volatile phase during this eruptive period. We apply Raman

spectroscopy to determine the different species contained in the vapor bubbles and calculate the relative

molar fraction of these end-members. By doing this, it will be possible to stablish the evolution in the

eruptive phases and to better constrict the composition of the source and its implications on the eruption

mechanisms. Volatiles are ubiquitous in volcanic products for this tectonic setting, and their study represents

an indirect observation on what’s occuring in the Earth’s interior. Analyses on fluid inclusions are key for

the understanding of eruptive processes, since their behavior depends mainly on the volatile content.

E1

SCiMAN2018 PLENARY

Flexoelectricity: bending-induced polarization, from bytes to bones

Gustau Catalán1,2, Fabián Vásquez-Sancho2, Kumara Cordero-Edwards2 , Raquel Nuñez2,

Jackeline Narváez2, Umesh Bhaskar2, Amir Abdollahi2, Neus Domingo2

1ICREA-Institució Catalana de Recerca i Estudis Avançats, Barcelona, Catalonia

2ICN2-Institut Català de Nanociència i Nanotecnologia, Barcelona Institute of Science and

Technology, Barcelona, Catalonia

Flexoelectricity is a material property whereby a strain gradient, such as bending, is converted into an

electric polarization. It is allowed by symmetry in all materials. It is present in all dielectrics and also in all

semiconductors studied to date. It is even present in biomaterials. Despite its universality, flexoelectricity is

relatively little-known because the strain gradients required to generate sizeable signals are difficult to

achieve at the macroscale. At the micro and nanoscales, however, it can be a big effect.

In this talk I will overview research on flexoelectricity, with emphasis on recent advances such as the

discovery of flexoelectricity in semiconductors and its consequences for photovoltaics, the ability to write

and read ferroelectric memories without using voltage, the influence of flexoelectricity on fracture

phenomena, and the fact that flexoelectricity may very well affect how bone fractures heal themselves.

F1

SCiMAN2018 INVITED

Magnetic Nanowires:

from synthesis and magnetic characterization to technological applications

Manuel Vázquez, Cristina Bran, José Ángel Fernández-Roldán, Oksana Chubykalo-Fesenko,

Rafael P. del Real and Agustina Asenjo

Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas,

28049 Madrid. Spain

Magnetic nanowires are currently attracting much attention owing to their technological applications as

well as for their fundamental interest on the magnetization reversal mechanisms in engineered nanowires.

An overview of the different applications will be introduced, from advanced spintronics and logic devices,

to magnetic sensors and to biomagnetic functionalization. Then, most recent results of the investigation in

our team will be overviewed. That includes particularly the design and electrochemical synthesis of arrays

of magnetic nanowires (i.e. 20 to 200 nm diameter, 1 to 50 micrometer length; FeCoNi-based

composition). The magnetization process in individual nanowires with controlled modulations in diameter

or composition (i.e., multilayered) is experimentally characterized by magnetic force microscopy,

magneto-optical Kerr effect, PEEM/XMCD or electron holography. Micromagnetic simulations complete

the studies for a deeper interpretation of the experimental results. As an example, the figure shows the

quite recently observation of magnetization ratchet in multisegmented FeCo/Cu nanowires with designed

increasing length of magnetic segments (images of the reversal process: simulated, left, and

PEEM/XMCD, right; ACS Nano 2018, 12, 5932) of interest for the controlled domain wall motion for

application in magnetic registers.

F2

SCiMAN2018 ORAL

Piezoelectric mimicry of flexoelectricity

Amir Abdollahi1, Fabián Vásquez-Sancho2,3, and Gustau Catalán2,4

1 Laboratori de Càlcul Numèric, Universitat Politècnica de Catalunya, Catalonia, Spain

2 Institut Català de Nanociència i Nanotecnologia, Catalonia, Spain 3 Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, San

José, Costa Rica 4 Institut Català de Recerca I Estudis Avançats, Barcelona, Catalonia

The origin of “giant” flexoelectricity, orders of magnitude larger than theoretically predicted, yet frequently

observed, is under intense scrutiny. There is mounting evidence correlating giant flexoelectric-like effects

with parasitic piezoelectricity, but it is not clear how piezoelectricity (polarization generated by strain)

manages to imitate flexoelectricity (polarization generated by strain gradient) in typical beam-bending

experiments, since in a bent beam the net strain is zero. In addition, piezoelectricity changes sign under

space inversion but giant flexoelectricity is insensitive to space inversion, seemingly contradicting a

piezoelectric origin. Here we show that, if a piezoelectric material has its piezoelectric coefficient

asymmetrically distributed across the sample, it will generate a nonzero bending-induced polarization

impossible to distinguish from true flexoelectricity even by inverting the sample. The effective flexoelectric

coefficient caused by piezoelectricity is functionally identical to, and often larger than, intrinsic

flexoelectricity: our calculations show that, for standard perovskite ferroelectrics, even a tiny gradient of

piezoelectricity (1% variation of piezoelectric coefficient across 1 mm) is sufficient to yield a giant effective

flexoelectric coefficient of 1  μC/m, three orders of magnitude larger than the intrinsic expectation value.

F3

SCiMAN2018 ORAL

Effect of flexoelectricity on the nano-mechanical properties of ferroelectrics

Kumara Cordero-Edwards1,2, Amir Abdollahi3, Hoda Kianirad4, Carlota Canalias4, Jordi Sort5, 6,

Neus Domingo1 and Gustau Catalan1,6

1Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB,

Bellaterra, Barcelona 08193, Catalonia 2DPMC-MaNEP, Université de Genève, Quai Ernest-Ansermet 24, 1211 Geneva, Switzerland 3Laboratori de Càlcul Numèric (LaCàN), Universitat Politècnica de Catalunya (UPC), Campus

Nord UPC-C2, E-08034 Barcelona, Spain 4Department of Applied Physics, KTH-Royal Institute of Technology, Roslagstullsbacken 21,

10691, Stockholm, Sweden 5Departament de Física, Universitat Autònoma de Barcelona (UAB), Edifici Cc, E-08193

Bellaterra, Spain 6 Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, E-08010

Barcelona, Catalonia

Hitherto, it has been believed that the mechanical properties are invariant with respect to space inversion,

that is to say that measuring them on one side or on the opposite side of a crystal should not change their

value, even when the material in question is crystallographically asymmetric, such as ferroelectrics.

However, this situation can change in the presence of strain gradients, because deforming a ferroelectric

material in an inhomogeneous way, will give two sources of polarization: the piezoelectric one due to strain,

and the flexoelectric one due strain gradients. These two polarizations can be parallel or antiparallel

depending on the ferroelectric polarity, which in turn will result in two different electrostatic energy costs

of the deformation. As consequence, the mechanical response of ferroelectrics depends not just on the

orientation but also on the sign of their polarization.

Our work demonstrates experimentally that, in the presence of strain gradients, mechanical inversion

symmetry breaks down: the mechanical response of ferroelectrics depends not just on the orientation but

also on the sign of their polarization. This result represents a paradigm shift in the physics of solid state

mechanics and fracture physics, and opens up new and interesting functional concepts such as mechanical

reading of polarization.

F4

SCiMAN2018 ORAL

Determination of nanomechanical properties of surfaces by atomic force

microscopy using higher harmonics

Federico Gramazio1, Matteo Lorenzoni2, Francesc Pérez-Murano2, Laura Evangelio1,2,

Jordi Fraxedas1

1Institut Català de Nanociència y Nanotecnologia - ICN2, CSIC and BIST, Campus UAB,

Bellaterra, Barcelona 08193, Spain 2Instituto de Microelectrónica de Barcelona IMB-CNM, CSIC, Campus UAB, Bellaterra,

Barcelona 08193, Spain

The determination of nanomechanical properties is an intensive topic of study in several fields of

nanophysics, from surface and materials science to biology. At the same time, amplitude modulation force

microscopy is one of the most established techniques for AFM nanoscale characterization. In this

presentation, we combine these two topics and propose a method able to extract quantitative

nanomechanical information from higher harmonic amplitude imaging in atomic force microscopy. With

this method it is possible to discriminate between different materials in the stiffness range of 1–3 GPa, in

our case thin films of PS-PMMA based block copolymers (Fig. 1). We were able to obtain a critical lateral

resolution of less than 20 nm and discriminate between materials with less than a 1 GPa difference in

modulus. We show that within this stiffness range, reliable values of the Young’s moduli can be obtained

under usual imaging conditions and with standard dynamic AFM probes.

We corroborate the method with a combined theoretical and experimental study of the dependence of

resonant higher harmonics of rectangular cantilevers of an atomic force microscope (AFM) as a function

of relevant parameters such as the cantilever force constant, tip radius and free oscillation amplitude as

well as the stiffness of the sample’s surface. The simulations, proved by the experimental study, give a

practical tool in order to optimize the range of the different parameters and obtain qualitative and

quantitative information.

Figure 1 - PS-PMMA images of topography and 6th higher harmonics

G1

SCiMAN2018 INVITED

Electronic transport in a single chiral molecule, towards to control spin

thermopower by magnetic field or temperature

Carlos Sabater1,2, Oren Tal1

1Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovot, Israel

2Departamento de Física Aplicada, Universidad de Alicante, Campus San Vicente del Raspeig, E-

03690, Alicante, Spain

A single chiral molecule attached between two metallic electrodes can act as a spin filter. This

phenomenon is based on the Chiral-Induced Spin Selectivity (CISS) effect that takes place when an

electron is transmitted along a chiral molecule. We want to take advantage of this effect to demonstrate a

new spin thermopower behavior that can be tuned by magnetic field or by the sign of an applied

temperature difference across the molecular junction. However, before arriving to this level of control,

questions as how a single helicoidal molecule can be anchored to the electrodes should be answered.

Using the Mechanically Controllable Break Junction (MCBJ) at low temperature, we have studied the

electronic transport of different helicenes molecules in order to recognize the different types of molecular

binding geometries in the junction. Beyond of the first towards steps, our results rebuild the different

structures and electronic properties of helicene-based on molecules.

Figure 1. Illustration of the molecular source implemented in the MCBJ experimental setup and temperature gradient

across the sample. Adapted from O. Shein Lumbroso et al. Nature 2018 (accepted).

G2

SCiMAN2018 ORAL

Effect of chemical treatment on the surface structure of Li1-x[Mn2]O4

Charles D. Amos1,2, Manuel A. Roldan2,3, John B. Goodenough1, Paulo J. Ferreira1,2

1The University of Texas at Austin, Materials Science and Engineering, Austin, Texas, USA

2International Iberian Nanotechnology Laboratory (INL), Braga, Portugal 3Arizona State University, Phoenix, Arizona, USA

Li[Mn2]O4 (LMO) is a well-known cathode material for Li-ion batteries, but it is plagued with cyclability

problems associated with the loss of Mn2+ to the organic liquid electrolyte during electrochemical cycling.

The surface disproportionation of Mn (2Mn3+ → Mn2+ + Mn4+) creates the Mn2+ and leads to a stabilization

of the surface of LMO through a surface reconstruction that creates a thin surface layer of Mn3O4 and a Li-

rich subsurface layer of Li1+x[Mn2]O4 [1]. We have applied an aqueous acid treatment, a non-aqueous

chemical delithiation, and an oxygen plasma treatment to LMO in order to understand how this surface

reconstruction is affected by chemical treatments. We find with TEM that Mn3O4 is a robust surface phase

in the Li1-x[Mn2]O4 system regardless of the chemical treatment and level of lithiation. The surface Mn3O4

phase is cubic whereas bulk Mn3O4 undergoes a cooperative Jahn-Teller distortion to tetragonal symmetry.

Thicker Mn3O4 surface layers are tetragonal.

1 Amos, C. D. et al, Nano Lett. 2016, 16, 2899–2906.

Figure 1. High-resolution HAADF STEM image

of the original LMO sample that shows the bulk

spinel framework of LMO (blue) as well as the

reconstructed surface of Mn3O4 (red) (ARM200F,

Dose Rate: 1.0 x 108 e-/Å2∙s, Dose: 5.5 x 105 e-/Å2,

GF: 170).

Figure 2. High-resolution HAADF STEM image

of oxygen-plasma-treated LMO showing a thick

Mn3O4 surface phase (red), thicker than the one

that occurs in untreated LMO (ARM200F, Dose

Rate: 1.0 x 108 e-/Å2∙s, Dose: 2.5 x 105 e-/Å2, GF:

79).

G3

SCiMAN2018 ORAL

Mechanical and electrical properties of nanostructured systems based on poly

(3,4-ethylenedioxythiophene) (PEDOT) aerogels of starch/κ-carrageenan for

electrochemical applications

Roy Zamora-Sequeira1, Carlos A. García-González2, Giovanni Sáenz-Arce 3, E. Avendano4,

Ricardo Starbird-Pérez1

1Escuela de Química, Tecnológico de Costa Rica, Cartago, Costa Rica.

2Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, R+D Pharma Group (GI-

1645), Facultad de Farmacia and Health Research Institute of Santiago de Compostela (IDIS),

Universidade de Santiago de Compostela, E-15782, Santiago de Compostela, Spain. 3Escuela de Física, Universidad Nacional de Costa Rica, Heredia, Costa Rica.

4Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, San

Pedro, Costa Rica.

Aerogels based on polysaccharides and structured with conductive polymers have great potential as devices

for various applications as sensors, due to their low density, low cost, good electrical and mechanical

properties. In this study, the nanoporous PEDOT-based materials were prepared through a nanostructured

template-assisted processing approach using starch/κ-carrageenan aerogels as templates. The biopolymer κ-

carrageenan contained in the template acted as a doping agent in the PEDOT-based material improving the

electrical and mechanical properties of the resulting nanostructured material. The physicochemical,

morphological, mechanical and electrical properties of the nanostructured PEDOT and templates were

characterized. These templates were effective for the nanostructuration of the conductive polymer resulting

in homogeneous and mechanically stable PEDOT nanostructures. Morphological properties of the resulting

conductive materials are promising for electrochemical applications due to their dual porosity and full pore

interconnectivity. The incorporation of κ-carrageenan to the nanostructured materials resulted in an increase

in the compressive strength of ca. 40% and a decrease in the electrical impedance of one order-of-magnitude.

Nanomechanical properties along with electrochemical delivering systems may allow being used as a

biocompatible material in biosensors.

G4 SCiMAN2018 ORAL

Model complexes of amorphous cobalt based water oxidation catalysts:

evidence of the role of the anion in the structure and redox properties

Esteban Rojas-Gatjens1,2, Diego González-Flores1,2,3, Roberto Urcuyo1,2,3,4, Leslie W. Pineda2,3,

and Mavis L. Montero1,2

1Centro de Investigación en Ciencia e Ingeniería de Materiales (CICIMA), San José, Costa Rica

2Escuela de Química, Universidad de Costa Rica, San José, Costa Rica 3Centro de Electroquímica y Energía Química (CELEQ), San José, Costa Rica

4Max Planck Institute for Solid State Research, Stuttgart, Germany

Pakhomovskite (Pakho: Co3(PO4)2·8H2O) and Erythrite (Ery: Co3(AsO4)2·8H2O)) are isostructural

compounds that present catalytic activity towards water oxidation and differ only in the anion. When Pakho

and Ery are operated in electrolysis for prolonged periods of time, they are transformed into an amorphous

cobalt oxide (CoCat). Typically, Ery exhibits a higher resistance towards amorphization under electrolysis

conditions. These results draw the attention to the anion effect in the catalytic activity, resistance against

corrosion and whether they play also a role in the structure of the catalyst once it becomes amorphous.

Tracking phosphate or arsenate in amorphous cobalt oxides is not an easy task. To address this problem,

we used the coordinating capabilities of bipyridine ligands to kidnap clusters from Pakho and Ery with the

aim of obtaining molecular complexes that represent the structure of amorphous cobalt oxide fragments

and shed light on the role of the anion. Through this methodology, two mononuclear isostructural

complexes containing phosphate or arsenate, and a cobalt-arsenate trinuclear cluster were obtained. We

observed three main binding modes of anions: i) both arsenate and phosphate can bind to cobalt forming a

µ-bridge; arsenate can also ii) form a bridge between two cobalt atoms and iii) expand the coordination

sphere to 5. Finally, we show that the anion affects also the position of the cobalt redox transition which

could have important implications in the catalysis.

H1

SCiMAN2018 ORAL

Determination, of the presence of a birefringent organic compound in the

elytra of beetles C. optima, using infrared spectroscopies

William E. Vargas1,2, Esteban Avendaño1, Marcela Hernández-Jiménez1, Daniel E. Azofeifa1,

Eduardo Libby3, Ángel Solís4 and Cynthia Barboza-Aguilar5

1Centro de Investigación en Ciencia e Ingeniería de Materiales & Escuela de Física, Universidad

de Costa Rica, San José, Costa Rica 11501 2Academia Nacional de Ciencias de Costa Rica, San José, Costa Rica 2050

3Centro de Investigación en Ciencia e Ingeniería de Materiales & Escuela de Química,

Universidad de Costa Rica, San José, Costa Rica 11501 4Departamento de Historia Natural, Museo Nacional de Costa Rica, San José, Costa Rica,1000 5Centro de Investigación en Estructuras Microscópicas, Universidad de Costa Rica, San José,

Costa Rica 11501

In 1971, Caveney [1] reported the presence of uric acid crystals within the chitin Bouligand structure of C.

resplendens and C. optima, among other species. The existence of such organic birefringent compound in

the elytrum of Chrysina beetles with metallic appearance was considered as an importan fitting parameter

for the theoretical modeling. Nevertheless, its existence has been recently disputed due to the high values

needed in the models versus the lack of success in attempting a chemical extraction by different groups. In this work, we report a detailed examination, for C. optima, by means of FTIR-ATR and μRaman

Spectroscopy, of samples prepared from the elytra upper surface of eight non-cured specimens. The volume

fraction of a uric acid-type compound was determined by infrared spectroscopy and then used in the fitting

of the optical model. The result obtained was in excellent agreement with respect to the measured spectra,

resulting in a unified description involving structural morphology, composition, dispersion of optical

constants, measured reflection spectra and photonic crystal characterization [2].

[1] Caveney, S. Cuticle reflectivity and optical activity in scarab beetles: The role of uric acid. Proc. R.

Soc. Lond.B 1971, 178, 205–225.

[2] Vargas, William, et al. Photonic Crystal Characterization of the Cuticles of Chrysina chrysargyrea and

Chrysina optima Jewel Scarab Beetles. Biomimetics, 2018, vol. 3, no 4, p. 30.

H2

SCiMAN2018 ORAL

Graphene-based lab-on-chip sensors for the detection and characterization of

C. difficile

Karla Cordero-Solano1,2,3, Sebastián Hernández Cinfuentes1, Katherine Acuña-Umaña1, 2, César

Rodriguez-Sánchez4, Giovanni Sáenz-Arce3, Leonardo Lesser-Rojas2, and Roberto Urcuyo1

1Centro de Investigación en Energía Química y Electroquímica, Universidad de Costa Rica, San

José, Costa Rica, 11501-2060. 2Laboratorio de Nano-Bio Sistemas, Centro de Investigación en Ciencias Atómicas, Nucleares y

Moleculares, Universidad de Costa Rica, San José, Costa Rica, 11501-2060. 3Departamento de Física, Universidad Nacional, Heredia, Costa Rica, 86-3000.

4Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San José,

Costa Rica, 11501-2060.

Around the world, 20-30% cases of diarrhea are due to nosocomial infections, whose main actor is C.

difficile. Its diagnostic is currently based on the presence of symptoms and positive evidence of toxins

associated with its pathogenicity, these techniques have high margins of false positive. Graphene as a

biosensor has shown to have a very high sensitivity, up to unimolecular detection limits. We oxidized

CVD Graphene using oxygen plasma until a good compromise between high coverage for subsequent

chemical modification and good electrical conductivity. Subsequently, aptamers designed for endospores

of C. difficile were anchored to the surface and verified by XPS. Afterwards, the specific endospore was

bind to the aptamer and detected by fluorescent microscopy. In parallel, a polydimethylsiloxane (PDMS)

based microfluidic device with constrictions has being developed and encapsulated to the graphene-oxide

(GO) sheets in order to concentrate the pathogen and have higher modification yield. Merging of this two

concepts allowed us to have a first prototype (Figure 1) of a lab-on-chip device for the detection of C.

difficile, hence preliminary results will be presented.

Figure 1. Prototype of a lab-on-chip device

for the detection of C. difficile.

H3

SCiMAN2018 ORAL

Biophotovoltaic system built from renewable carbon: integration of graphene

hybrids and the phototrophic protein bacteriorhodopsin

Claudia Villarreal1,2, Venkatesan Renugopalakrishnan3, Ashok Mulchandani2,4

1Escuela de Ciencia e Ingeniería de Materiales, Tecnológico de Costa Rica, Costa Rica

2Materials Science and Engineering, University of California Riverside, USA 3Chemical and Chemical Biology Department, Northeastern University, USA, USA

4Chemical and Environmental Engineering, University of California Riverside, USA

Solar energy has the highest potential of the Earth´s renewable

energy sources. Its conversion into electrical power to meet the

demand of our economy is an ongoing effort. The leading

technology, silicon, and the emerging alternative technologies,

like CdTe and perovskites, require energy intensive

manufacturing processes, toxic chemicals and/or non-abundant

minerals that cause problems thorough their life cycle such as

pollution and social conflicts. Since the negative impacts of PV

technology are mainly derived from material selection and

manufacturing processes, new advanced technology that uses

abundant, renewable and biodegradable materials, as well as

cleaner fabrication processes needs to be developed for the

sustainable future of solar energy. Carbon is an abundant

element that exhibits a broad assortment of allotropic forms and

electrical behavior, and can make up an infinite variety of functional biomolecules when combined with

other plentiful elements. We propose the combination of graphene-ZnO hybrids with a phototrophic protein,

bacteriorhodopsin (bR), to develop a bio-sensitized solar cell. The graphene is used to replace the tin oxide

transparent conductor in the photanode, while the bR is used to replace the traditional synthetic dyes that

absorb the visible sunlight. Two different morphologies and fabrication approaches of nano-ZnO are

investigated to create graphene heterostructures for photoanode platform: commercial nanoparticles and

vertical nanorods in situ grown by electrodeposition. The immobilization of the bR on the ZnO and the

mediator selection are optimized in function of the photoelectric response of the system. We investigate the

structure, energy alignment and electrical behavior at the different interfaces of the device,

graphene/ZnO/bR/electrolyte, and correlate them to processing parameters. The photovoltaic performance,

internal resistance and electron kinetics of the cells are characterized by photo-electrochemical methods.

The introduction of heterostructures using carbon nanomaterials and biomolecules derived from renewable

sources together with low cost, non-toxic semiconductors constitute the beginning of a new era for

sustainable bio-photovoltaics, which is supported by the latest advances in genetic engineering and

nanotechnology. This work demonstrates the viability of sustainable alternatives to replace traditional costly

and harmful materials and provides a framework to the design of novel bio-nanointerfaces for future

technological applications.

hν

Red

Oxhν

e-

RedOx

Powergeneration

Power loss

Photo-Electrode

Red

Ox

e-Photoanode

Red

Ox

Electrolyte

e-

GrapheneZnO BioSensitizer Counterelectrode

Figure 1. Biophotovoltaic system built

from renewable carbon sources

H4

SCiMAN2018 ORAL

Electrochemical characterization of poly(3,4-ethylenedioxythiophene)/

κ-carrageenan as a biocompatible conductive coat for biologic applications

Priscila Hernández1, Karla Ramírez2, Fernando Alvarado1, E. Avendaño3, Ricardo Starbird4

1Escuela de Ciencia e Ingeniería de Materiales, Instituto Tecnológico de Costa Rica, Costa Rica

2Escuela de Biología, Instituto Tecnológico de Costa Rica, Costa Rica 3Escuela de Física, Universidad de Costa Rica, Costa Rica

4Centro de Investigación y de Servicios Químicos y Microbiológicos CEQIATEC, Escuela de

Química, Instituto Tecnológico de Costa Rica, Costa Rica

Poly(3,4-ethylenedioxythiophene) (PEDOT) is synthesized through a micellar dispersion that allows

incorporation of biomolecules into this conductive polymer layer. A PEDOT:κ-carrageenan (κC) system

was obtained by electrodeposition and it was compared with a standard PEDOT:sodium dodecyl sulfate

electrode coat. The electrochemical behavior and the oxidation level after 1000 cycles were studied through

cyclic voltammetry and μRaman spectroscopy. The oxidation ratio in the PEDOT increased while

electrochemical activity decreased in both cases. Moreover, the PEDOT:κC system allowed the

immobilization of the acetylcholinesterase enzyme, which retained its activity. The unique combination of

properties is a key feature in the bioelectronics field.

I1

SCiMAN2018 PLENARY

The potentialities of Sirius, the new Brazilian Synchrotron Light Source, for

the Research in Advanced Materials and Nanotechnology

Harry Westfahl Jr.

Laboratório Nacional de Luz Síncrotron (LNLS), Centro Nacional de Pesquisa em Energia e

Materiais (CNPEM), Campinas-SP, Brazil

The application of synchrotron radiation in a large variety of fields, from biology to nano-science and

nanotechnology, has increased steadily worldwide. To a large extent this is a result of the availability of

much brighter synchrotron light sources, which provided new experimental techniques to investigate

different aspects of matter, from atomic organization to electronic structure. Recently, new developments in

accelerator technology are paving the way for even brighter sources, which are being named fourth-

generation storage rings. Sirius, the future new Brazilian synchrotron light source, is one of the first two

such machines in construction in the world. Its first experiments are expected by 2019 and it is being planned

to be a state-of-the-art light source, providing cutting edge research tools, like 3D chemical, magnetic and

structural mapping with nanometer resolution.

The Sirius project is designed and executed by the Brazilian Synchrotron Light Laboratory - LNLS, which

was also responsible for the construction of the current second-generation Brazilian light source, UVX, the

first synchrotron in the southern hemisphere, and still the only one in Latin America. In this talk I will

provide an overview of the main characteristics of Sirius and its potentialities for the research in advanced

materials and nanotechnology, as well as the status of the project.

Figure 1: Sirius construction site on August 14th 2018

J1

SCiMAN2018 INVITED

CO2 capture capacity of open-cell Mg foams and the effect of lithium

impregnation

Ignacio A. Figueroa

Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México (UNAM),

Circuito Exterior S/N, Cd. Universitaria, Cd. Mx., México 04510

Carbon dioxide (CO2) is a major greenhouse gas, commonly formed by the combustion of fossil fuels.

Recently, several systems such as zeolites, activated carbon, ceramic alkaline, calcium and magnesium

oxides have been proposed for the CO2 capture. Open-cell Mg foams present a large surface area, which can

be oxidized to form Mg oxides with attractive possibilities to use them as structured CO2 captors. Open-cell

Mg foams with mean pore size of 350 microns, relative density of 0.33 and surface area (BET) of 5.42m2/g

were used to carry out the surface oxidation and CO2 capture experiments. The CO2 capture capacity was

studied at low temperatures (between 40 and 60°C) and with a relative humidity ranging from 40 to 80%.

Optical microscopy and XRD techniques were used to characterize the structure of the foams and to identify

the superficial oxide formed over the cells. The final products formed after the isothermal CO2-H2O capture

experiments were identified by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). The

products formed after the isothermal capture process were thermally decomposed by mean of

thermogravimetric analysis (TGA), this in order to quantify the amount of CO2 captured for the MgO layer.

The results showed that the Mg foams with a superficial thicknesses layer of 8 microns of MgO showed the

highest CO2 capture capacity (0.87 mmol/g) analyzed at 60°C and 80% of relative humidity. The mechanical

properties (yield strength, ultimate strength, elastic modulus, etc.) of the Mg foams and the considerable

CO2 capture capacity obtained in this work, supports the possibility of using them for functional applications

as structured CO2 captors. This work was financially supported by UNAM-DGAPA-PAPPIT (No.

IN101016).

J2

SCiMAN2018 ORAL

Erythrite as water oxidation catalyst: Role of the buffer in the amorphization

kinetics

María G. Fernández Scott1, David Sánchez Berrocal2, Roberto Urcuyo1,2, Mavis L. Montero2,

Diego Gonzáles-Flores 1,2

1Centro de Electroquímica y Energía Química (CELEQ), Universidad de Costa Rica, 11501

2060, San José (Costa Rica) 2Centro de investigación en Ciencia e Ingeniería en Materiales (CICIMA) Universidad de Costa

Rica, 11501 2060, San José (Costa Rica)

Water splitting as a source of electrons and protons to form non-fossil fuels, will eventually become one of

the few possibilities to sustainably store renewable energy. Nevertheless, water oxidation catalysts that

can work efficiently under benign conditions, close to neutral pH, and perform under high stability are still

a challenge. Crystalline catalysts used for water splitting tend to undergo amorphization when electrolysis

is carried out. It is believed that the anion plays a preponderant role in the amorphization process.

However, little research has been done on the associated phenomena. The present study uses Erythrite

[Co3(AsO4)2*8H2O], a cobalt arsenate mineral with catalytic activity for water oxidation to study this

phenomena. Arsenate can be easily quantified, thus allowing the study of anionic exchange kinetics when

Erythrite is used for electrolysis. In a borate solution, arsenate is rapidly exchanged. This behavior is

directly related to the amorphization of the catalyst. In a phosphate solution, the crystalline structure

remains for a longer time and the anion exchange occurs to a lesser degree. The present study shows that

the anionic exchange has a prevailing role in the amorphization of the catalyst, and that such process

depends on the identity of the anion.

J3

SCiMAN2018 ORAL

Generation of nanotopographic bactericidal surfaces

Sergio A. Paniagua1,2, Esteban Rojas3, Luis Carlos Murillo4, Javier Villalobos1,3, Gabriela

Montes de Oca1, Reinaldo Pereira1, Jose R. Vega1,5

1Laboratorio Nacional de Nanotecnología (LANOTEC), San José, Costa Rica

2Sección de Química, Universidad de Costa Rica Sede Occidente, Alajuela, Costa Rica 3Escuela de Química, Universidad de Costa Rica Sede Rodrigo Facio, San José, Costa Rica

4Escuela de Mecatrónica, Universidad Invenio, Guanacaste, Costa Rica 5Escuela de Química, Universidad Nacional, Campus Omar Dengo, Heredia, Costa Rica

In nature, some fauna protect themselves from harmful microorganisms through biostructures on their wings

or skin that mechanically stress attached bacteria, resulting in bactericidal surfaces. This strategy, as opposed

to a chemical mechanism, reduces the likelihood of developing bactericidal resistance. In this work, we have

generated different suitable alternatives for the creation of antimicrobial surfaces through the development

of nanometric pillars and spikes on a variety of surfaces. Modification of the protocol for anodization of

aluminum can lead to alumina nanopillars of a few hundred nanometers in height and about a hundred

nanometers wide, which have shown bactericidal efficiency of ca. 75% over untreated aluminum surfaces.

Moreover, using soft lithography, we have created similar structures on medical-quality colorless elastomers

that have the potential to be used as bactericidal films to cover any surface. We also address our current

efforts on deposition of ZnO crystals in the shape of spikes on stainless steel as an additional bactericidal

technology.

J4 SCiMAN2018 ORAL

Characterization of Velvet worm (Onychophora: Peripatidae) secretions by

Atomic Force Microscopy (AFM) and Dynamic Light Scattering (DLS) for

eventual replacement of synthetic materials

Laria Rodríguez1, Karen Oviedo2, Bernal Morera-Brenes2, Esteban Avendano-Soto3, Ricardo

Starbird4, Giovanni Sáenz-Arce5,

1Escuela de Ciencia e Ingeniería de los Materiales, Instituto Tecnológico de Costa Rica, Cartago,

Costa Rica. 2Laboratorio de Sistemática, Genética y Evolución (LabSGE), Escuela de Ciencias Biológicas,

Universidad Nacional, Heredia, Costa Rica. 3Centro de Investigacion en Ciencia e Ingenieria de Materiales (CICIMA) y Escuela de Fisica,

Universidad de Costa Rica. 4Escuela Química, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica.

5Departamento de Física, Universidad Nacional, Heredia, Costa Rica.

The secretions of the Velvet worm (Onychophora: Peripatidae) has recently attracted attention because of

its adhesion properties. The effects of the acidity in the molecular structure of the secretion have been

studied regarding the dispersion and their respectively aggregates. The samples were diluted in a 1:10 ratio

at different pH value. Infrared Spectroscopy (FTIR) was used to characterize the main functional groups.

Meanwhile, Dynamic Light Scattering (DLS) technique was applied to study the size and interaction of the

sample in dispersion. The characterization of the aggregates was carried out by Atomic Force Microscopy

(AFM), allowing the topographic and mechanical properties (i.e. Young's modulus) of the sample. The

dispersion of the particles was favored in acidic media (pH: 3), since it was found a higher agglomeration

rate at basic pH.

Figure 1. Atomic force microscopy and dynamic light scattering: a) Dilution in water, b) Dilution in a buffer pH: 3 and c)

dilution in a buffer pH: 9 5. Continuous line in a time 0 and the dotted line represents the concentration after 10 minutes.

P01

SCiMAN2018 POSTER

Stability and orientation of organic anions on polypyrrole surfaces by

molecular dynamics simulation

Eric G. Romero Blanco1, Eric Castellón Elizondo2

1Escuela de Química, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica, 159

2Escuela de Química, Universidad de Costa Rica, San José, Costa Rica, 11501

In order to determine the capacity of the polypyrrole to incorporate carboxylate anions, classical molecular

dynamics simulation and importance sampling were used to predict the stability, relative strength and

orientation of the anions acetate, propionate and benzoate, interacting in aqueous medium with surfaces of

polypyrrole in its completely reduced and completely oxidized state.

The stability of the interaction was determined from the estimation of the Helmholtz energy binding

profile (potential of mean force). The orientation and relative strength of the interaction was determined

by calculating the profile for the variation of the angle formed by the dipolar moment of the anion with the

polypyrrole surface. These profiles were obtained as a function of the distance between the anion and the

surface of polypyrrole.

As a result of this simulation, it was obtained that the interaction of acetate and propionate was double

more stable with the oxidized surface than with the reduced surface, due to the strong attraction between

the dipole of the anions and the charges present in the oxidized surface. For benzoate there was no

difference in the stability of interaction with both surfaces, because the most important attraction was

given by pi-stacking interactions between the phenyl group and the polypyrrole chains and not by the

effect of the dipole moment of the anion.

The anions acetate, propionate and benzoate showed the possibility of contact interactions with the surface

of polypyrrol and to allow orientations for the dipolar moment from parallel to oblique (inclined) in

relation to it. Only for the benzoate anion was there the possibility of a configuration with penetration on

the membrane surface.

P02 SCiMAN2018 POSTER

Study of the thermochromic behavior on Polymethylmethacrylate-Vanadium

Oxide matrices for thermochromic windows applications

Fernando Alvarado-Hidalgo1, Natalia Murillo-Quirós2, Esteban Avendaño3, Ricardo Starbird-

Pérez4

1 Centro de Investigación y Extensión de Ingeniería de los Materiales; Instituto Tecnológico de

Costa Rica, Cartago, Costa Rica 2 Escuela de Física; Instituto Tecnológico de Costa Rica, Cartago, Costa Rica

3 Centro de Investigación en Ciencia e Ingeniería de Materiales; Universidad de Costa Rica, San

Pedro, Costa Rica 4 Escuela de Química; Instituto Tecnológico de Costa Rica, Cartago, Costa Rica

This research has been developed to evaluate the application of spin coating as Polymethylmethacrylate

(PMMA) film processing technique. PMMA was used as a polymeric matrix to disperse vanadium Oxide

(VO2) and stearic acid for glazing thermochromic applications. The thermal properties of commercial grade

VO2 and a hydrothermal synthesized vanadium oxide were analyzed using Differential Scanning

Calorimetry (DSC). Besides, DSC analysis confirmed the thermochromic reversible behavior of vanadium

oxide in the PMMA matrix (Fig. 1), finding that the phase change VO2 occurs at 65°C with 5 °C as thermal

hysteresis. Finally, using an analysis of variance it was found that the spin speed set in the processing of

polymer films has a major effect on the polymer film thickness with 5% significance, reaching a minimum

thickness of approximately 3 μm.

Fig. 1. Thermochromic behavior of VO2 in a PMMA matrix.

P03

SCiMAN2017 POSTER

Electrophoretic deposition of crystalline nanocellulose based monolayer

coatings and composite chitosan/bioglass-alginate/nanocrystalline cellulose

multilayer coatings

Álvaro Urrutia Núñez1, Yoselin Jiménez Alpizar1, Melissa Camacho2, José Roberto Vega

Baudrit2, Sannakaisa Virtanen3, Aldo R Boccaccini4, Luis Cordero-Arias1,3

1Escuela de Ciencia e Ingeniería de los Materiales, Costa Rican Institute of Technology, Cartago

159-7050, Costa Rica 2Laboratorio Nacional de Nanotecnología, CENAT, Pavas, San José, Costa Rica.

3Institute of Surface Science and Corrosion, University of Erlangen-Nuremberg, Martensstraße 7,

D-91058 Erlangen, Germany 4Institute of Biomaterials, University of Erlangen-Nuremberg, Cauerstrasse 6, D-91058 Erlangen,

Germany

Nanocellulose particles (CNC), synthesized from pineapple waste, where used for the development a of

monolayer and multilayer biocompatible coatings for bone regeneration via electrophoretic deposition

(EPD). This tacking advantage of cellulose´s increasing interest on the biomedical field and its availability

in Costa Rica. Stable suspensions with and without biocompatible saccharides were development for a

suitable coating deposition. Monolayer arrangements were made to study anticorrosive and superficial

properties that CNC provides to AISI 316L biomaterial alloy as a biocompatible coating. Furthermore

Bioglass® particles were used for the production of multilayer systems to impart bioactivity to the system.

Morphology and composition of the coatings were studied using SEM, Optical profilometry, FTIR, TGA-

DSC, to verify the formation of coatings on the substrate surface. Contact angle and surface energy

measurements were done in order to evaluate the possibility of protein transport. The electrochemical

behavior of the coatings was analyzed using PC, OCP and EIS. Results showed that the homogenous

multilayer coatings were successfully deposited incorporating all different polymers and Bioglass®, and

that the different coatings can tailor the substrate degradation.

P04

SCiMAN2018 POSTER

In-situ calcium phosphate synthesis on biomedical grade stainless steel AISI

316L via electrochemical deposition: particles development and degradation

control

Natalie Cruz-Gamboa, María Celeste Monge-Naranjo, Valeria Richmond-Blanco, Yoselin

Jiménez-Alpizar, Luis Cordero-Arias

Escuela de Ciencia e Ingeniería de los Materiales, Costa Rican Institute of Technology, Cartago

159-7050, Costa Rica

Stainless steel has developed great interest for biomedical applications due to their low cost, high corrosion

resistance, excellent biocombability and mechanical properties. However, when used as implant they do not

form a strong chemical bond with natural bone. In order to make stainless steel more biocompatible and

bioactive, hydroxyapatite Ca5(PO4)3(OH) has been added as coating. Hydroxyapatite induces bone tissue

growth due to its structural and chemical similarities to mineral components of natural bones and reduce the

adverse reactions. In this research AISI 316L substrates were coated with hydroxyapatite by electrochemical

deposition from a solution containing Ca (NO3)2 and NH4H2PO4 at 70ºC, without previous surface

treatments. To analyze the coating composition, morphology and properties, scanning electron microscopy

(SEM) and X-ray diffraction were used, which confirmed the formation of hydroxyapatite particles. On the

other hand, via electrochemical characterization methods it was confirmed that HA coatings decreases the

degradation behavior of the metallic substrates.

P05 SCiMAN2018 POSTER

Electrochemical flow detection sensor for determination of mancozeb

pesticide in water based on Poly (3, 4-ethylenedioxythiophene) (PEDOT) with

carbon nanotubes and gold nanoparticles

Roy Zamora-Sequeira1, Allison Gómez-Calvo2, Fernando Alvarado-Hidalgo3, Diana Roble-

Chaves2, Giovanni Sáenz-Arce4, E. Avendaño5 & Ricardo Starbird-Pérez2

1Escuela de Química, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica.

2Centro de Investigación y de Servicios Químicos y Microbiológicos (CEQIATEC), Instituto

Tecnológico de Costa Rica, 159-7050 Cartago, Costa Rica. 3Centro de Investigación y Extensión de Ingeniería de los Materiales (CIEMTEC), Instituto

Tecnológico de Costa Rica, 159-7050 Cartago, Costa Rica. 4Escuela de Física, Universidad Nacional, Heredia, Costa Rica.

5Centro de Investigación en Ciencia e Ingeniería de Materiales (CICIMA), San Pedro, Costa

Rica

Costa Rica is one of the countries with the largest consumption of pesticides per hectare in the world.

Therefore, it is essential to evaluate the presence of this substance in water. Gold electrodes were modified

with poly(3,4-ethylenedioxythiophene) along with multiple-walled carbon nanotubes (MWCNT) and gold

nanoparticles (AuNPs) to detect Mancozeb in water in a continuous flow cell. The electrochemical

behavior of the modified electrode and the surface properties were characterized by cyclic voltometry (CV)

and atomic force microscopy (AFM), respectively. In this research, we used a continuous flow cell to

quantify Mancozeb in commercial formulations and a reference material. The PEDOT/MWCNT/AuNP

modified electrode provides a robust electrochemical response in the linear range, as well as a rapid method

in a solvent reduction system.

P06

SCiMAN2018 POSTER

Acetylcholinesterase immobilization into a PVA/PVA-SbQ matrix on

microplates for high-throughput screening of reversible and irreversible

inhibitors

Karla Ramírez-Sánchez1, Inés Ardao2, Ricardo Starbird-Pére3

1Escuela de Biología, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica

2BioFarma group, Center for Research in Molecular Medicine and Chronic Diseases-CiMUS,

Universidade de Santiago de Compostela, Santiago de Compostela, España 3 Escuela de Química, Tecnológico de Costa Rica, Cartago, Costa Rica

Enzymes catalyze a diverse set of reactions that are involve in all life processes. Acetylcholinesterase

(AChE) hydrolyses the neurotransmitter acetylcholine at cholinergic synapses. AChE inhibition causes to

acetylcholine accumulation, disrupted the muscular and neurologic process and influences respiratory

problems. Hence, this enzyme serves as the primary target of acetylcholinesterase inhibitors applied as

relevant drugs (reversible inhibitors applied in Alzheimer’s and Parkinson’s diseases) and toxins

(irreversible inhibitors such as organophosphorus compounds). Robust assays for High-throughput

screening (HTS) enable the testing of large numbers of chemical substances in the discovery and

development of AChE inhibitors. In this work, AChE was immobilized into a polymeric matrix of a mixture

of poly (vinyl alcohol) (PVA) and PVA-SbQ (stilbazole quaternized) on 96 well microplates. The enzyme

immobilization facilitated to carry out inhibition assays of Donepezil Drug and Chlorpyrifos pesticide. It

was possible to calculate the IC50 value for the reversible and irreversible inhibitors, re-use of microplates

and the reduction of cost in the high-throughput drug screening assays.

P07

SCiMAN2018 POSTER

Electrode Nanogap-Enabled and Dielectrophoretically Assisted Electrical

Auto-Correlation Spectroscopy of Low-Copy Number of Proteins

Alejandro Martínez-Brenes1,3, Andrés Hernández-Jiménez1,2, Jeremy Caldwell-Chacón1,2, Katrin

Vu4, Gerhard Blankenburg4, Li-Ling Yang 4, Chia-Fu Chou4 and Leonardo Lesser-Rojas1,2

1Laboratorio de Nano Bio Sistemas, Centro de Investigación en Ciencias Atómicas, Nucleares y

Moleculares, Universidad de Costa Rica, San José, Costa Rica. 2Escuela de Fisica, Universidad de Costa Rica, Costa Rica

3Escuela de Ciencia e Ingeniería de los Materiales, Instituto Tecnológico de Costa Rica, Cartago,

Costa Rica 4Institute of Physics, Academia Sinica, Taipei, Taiwan (R.O.C.).

Important efforts have been made in recent years to detect, analyze and manipulate single or low-copy

number of biological molecules that can contribute to the fundamental understanding of biological systems.

To this aim, electronic detection is an essential tool that is constantly experiencing significant advances

regarding miniaturization, faster readouts, higher S/N ratios and compatibility to aqueous mediums.

This paper reports the progress of acquiring information from electronic signatures of low-copy number of

molecules by implementing an Electrical Auto-Correlation Spectroscopy (ECS) technique. This approach

is inspired on the electrical equivalent of fluorescence cross-correlation spectroscopy, but our method differs

from that group since we measure and auto-correlate the fluctuations of current intensities across a

dielectrophoretically (DEP) trapped low-copy number of R-Phycoerythrin (RPE) molecules in a 5-15 nm

gap between Au/Ti electrodes on a 7 x 7 mm2 Si/ SiO2 chip.

In this work, besides the optical fluorescence confirmation of the RPE trapping by DEP means, an

autocorrelation analysis was performed to obtain intrinsic information from the acquisition of conductance

signatures for individual AC field conditions. Biophysical parameters such as diffusion coefficients and the

number of molecules are quantitatively determined from a 3D FCS fit model. Fitting data suggests the

effective trapping of molecules in the device due to a reduced diffusion coefficient (normally 40 µm2/s for

freely-diffusing RPE) and the presence of a low-copy number of proteins in the electronic detector.

Dimensions of the optical focal volume from the FCS model is recognized in our approach as a threshold

∇𝐸𝑟𝑚𝑠2 volume, in which the DEP force exceeds molecular diffusion; and its dependency with the AC

voltage amplitude was calculated from a 3D Multiphysics simulation towards building a more

comprehensive fitting function that helps to better quantify the number of molecules trapped in the nanogap.

Variables of the experiment that may modify the autocorrelation curves such as protein concentration, salt

concentration, monochromatic light exposure, DEP trapping parameters (AC amplitude voltage, frequency)

and DC voltage set between the nanoelectrodes, are currently explored for a more accurate parameter

estimation and deeper comprehension of the proposed analysis. Our approach might open up a simple way

for multifunctional quantification of low-concentration heterogeneous sample and small molecule analysis

at the single or few molecules level.

P08

SCiMAN2018 POSTER

Development of a computational model for high-pressure torsion optimization

Víctor Berrocal-Argüello, Alexander Campos-Quirós, Fabián Araya-Mora, Jorge M. Cubero-

Sesin

Centro de Investigación y Extensión en Materiales (CIEMTEC), Escuela de Ciencia e Ingeniería

de los Materiales, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica

Severe plastic deformation (SPD) by high-pressure torsion (HPT) it’s used to achieve enhancement in

mechanical properties as strengthening due the ultrafine-grained (UFG) microstructure obtained. This

process can be improved by understanding stress and strain distribution, hardening behavior and the sticking

friction accomplished. Taking this into account, a computational model was developed using finite elements

method (FEM) in order to analyze the stress and strain behavior of HPT applied to low carbon steel samples

of AISI 1020. Microhardness tests were carried out to samples under ¼, ½ and 1 turn of HPT in order to

correlate the results obtained in the model.

P09

SCiMAN2018 POSTER

Electronic and optical properties of tetragonal germanium dioxide using

quantum espresso suit

María Gabriela Campos Fernández1, Federico Muñoz Rojas1,2

1Escuela de Física, Universidad de Costa Rica, San José, Costa Rica 11501

2Centro de Investigaciones en Ciencia e Ingeniería en Materiales, San José, Universidad de Costa

Rica, Costa Rica 11501

Using quantum espresso suit, optical properties of tetragonal germanium oxide have been obtained.

Comparing lattice parameters for different pseudopotentials shows that PBE functional type with ultrasoft

pseudopotential is in agreement with initial positions. Also, bands and DOS have been calculating showing

a semiconductor behavior. The dielectric function was calculated. This material has optical properties useful

for optical aplications1.

1 Qi-Jun Liu, Zheng-Tang Liu, Li-Ping Feng and Hao Tian Solid State Sciences 12 (10) 1748 (2010) DOI:

10.1016/j.solidstatesciences.2010.07.025

P10

SCiMAN2018 POSTER

Design and simulation of flexible and interdigitated thin-film electrodes for

impedance spectroscopy

Gerardo Valladares-Castrillo1, Jorge Sandoval-Sandoval1, Juan J. Montero-Rodríguez2, Ricardo

Starbird Pérez3

1Escuela de Ciencia e Ingeniería en Materiales, Tecnológico de Costa Rica, Cartago, Costa Rica

2Escuela de Ingeniería Electrónica, Tecnológico de Costa Rica, Cartago, Costa Rica 3Escuela de Ingeniería Química, Tecnológico de Costa Rica, Cartago, Costa Rica

Among the different biosensing technologies in development, impedance biosensors stand out because they

offer significant advantages to portable and multi-analyte detections. Interdigitated electrodes (IDE) are a

common configuration used for impedance biosensors. The geometry of this configuration allows to increase

the sensitive area, keeping a low impedance in a high surface-to-volume ratio, therefore exhibiting a higher

sensitivity to surface interactions compared to other designs. The aim of this work is to present some features

to be considered in the design and manufacture of interdigitated electrodes. In addition, the results are

validated by a computational simulation using the finite element method (FEM) in order to generate a

reliable and repeatable procedure. The results confirm that electrode geometry and configuration have a

significant effect on sensor performance.

P11 SCiMAN2018 POSTER

Fabrication of rolled-up metal-dielectric multilayers

Luis Ramirez-Ramirez1,2, Esteban Bermúdez-Ureña1 and Ullrich Steiner1

1Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg,

Switzerland 2Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica,

San José, Costa Rica 11501

A thin film self-rolling technique was implemented to explore the fabrication of a hyperbolic metamaterial.

By means of microfabrication techniques such as photolithography and thin film deposition, and exploiting

the residual stress relaxation upon selective etching of a sacrificial layer, it was possible to fabricate micro-

rolls of a gold and silicon dioxide bilayer, achieving a metal-dielectric multilayered structure. The

characterization of the rolls involved optical microscopy, scanning electron microscopy and reflection

spectrometry. Furthermore, nano-hole array patterns were transferred onto the multilayers by means of a

focused ion beam, and their behavior was measured with reflection spectrometry and compared to finite-

difference time-domain optical simulations.

P12 SCiMAN2018 POSTER

A study of electric properties in Graphene and Borophene β12 nanoribbons

Federico Muñoz-Rojas1,2, Isaac Villalobos Gutiérrez1

1Escuela de Física, Universidad de Costa Rica

2Centro de Investigación en Ciencia e Ingeniería de Materiales (CICIMA),

Universidad de Costa Rica

A study of graphene and borophene β12 is made by comparing their electrical properties. First a bulk analysis

is made between the two materials, comparing their band structure describing electron motion of Dirac

fermion nature.1,2 Then we focus on nanoribbons (zigzag, armchair for different widths and 3 cases of

borophene β12 armchair, a unit cell with one edge of 2 atoms and the other edge with 3 atoms, a unit cell

with both edges of 3 atoms)3 of both materials with width ranges from 15 to 20 angstroms approximately,

band structure analysis is done for ferromagnetic and antiferromagnetic configurations, and an electric field

applied across the ribbon searching for half-metal behavior as predicted by Cohen and Louie.4

1 F. Muñoz, (2009). Transporte electrónico en cintas de Grafeno. Ph.D. Universidad de Alicante.

2 B. Feng, O. Sugino, et al Phys. Rev. Lett 118 , 9 (2017).

3 S. Izadi, M. Bagheri, Nano-Micro Lett. 10, 1 (2018).

4 Young-Woo Son Marvin L. Cohen and Steven G. Louie, Nature. 444, 7117 (2006).

P13

SCiMAN2018 POSTER

Electromagnetic interference shielding by the use of open-cell aluminum

foams

Francisco Rodríguez-Méndez1, Marcela Meneses-Guzmán2, Bruno Chinè1

1Escuela de Ciencia e Ingeniería de los Materiales, Instituto Tecnológico de Costa Rica, Cartago

Costa Rica 2Escuela de Ingeniería en Producción Industrial, Instituto Tecnológico de Costa Rica, Cartago

Costa Rica

With the rapidly increasing usage of computers and wireless communication technology, the constantly

upgrading and renewing of electronic equipment, and the increase of digital system working frequency,

generation and propagation of electromagnetic energy are becoming one of the major concerns. Any

electronic device that transmits, distributes or uses electrical energy creates electromagnetic interference

(EMI). Therefore, a proper shielding against this phenomenon is an essential requirement to ensure the

continuous functionality and integrity of the electronics and their components, and also to reduce the

radiation energy received by the human body.

Metal foams, a class of novel and multifunctional materials, have attracted engineers worldwide because of

their incomparable combination of lightweight structure, good acoustic and thermal isolation properties,

strong impact absorption, and vibration damping capabilities. In this work we evaluate the attenuation

potential against electromagnetic interference (EMI) of an open cell aluminum foam with a uniformly and

regular distributed matrix. By using the simulation environment of ANSYS Electromagnetics the incident,

attenuated, and total EM fields were calculated in a wide range of frequencies, showing that this kind of

material possesses good attenuation capabilities against electromagnetic interference.

P14 SCiMAN2018 POSTER

Solid electrolyte POM-PVA in aluminum-air batteries

Anyie Atencio1, Diego González1, Mavis Montero2

1Centro de Electroquímica y Energía Química

2Centro de Investigación en Ciencias e Ingeniería de Materiales, Universidad de Costa Rica, San

José, Costa Rica 11501

Al-air batteries are the candidate for the power source of electric vehicles (EVs) since its high theoretical

energy density (2791 Wh kg-1). However, these batteries have problems such as corrosion aluminum anode

and filtration electrolyte which limit its commercial development. This study presents a novel solid

electrolyte based on a polyvinyl alcohol (PVA) gel and polyoxometalates (POMs). The POM-PVA system

an alternative electrolyte to improve battery performance with low cost and ease synthesis.

P15

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Characterization of a 10-ton High-Pressure Torsion equipment to generate

phase transformations in commercially pure titanium

Mildred Chaves1, Adrián Quesada Martínez1, Fabián Araya Mora1, Jorge M. Cubero-Sesin1,

Zenji Horita2,3

1Centro de Investigación y Extensión en Materiales (CIEMTEC), Escuela de Ciencia e Ingeniería

de Materiales, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica. 2Department of Materials Science and Engineering, Kyushu University, Fukuoka 819-0395,

Japan 3International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University,

Fukuoka 819-0395, Japan

Titanium is an element with advantageous chemical and mechanical properties: high specific gravity, high

corrosion resistance and high biocompatibility, therefore it has numerous biomedical applications such as a

material for implants. High-pressure torsion (HPT) processing generates a nanostructured material with

enhanced mechanical properties and osteointegration with respect to conventional microstructures. For this

research, discs of commercially pure titanium were processed by HPT at room temperature, using P=2, 4,

6, 8, 10 and 12 GPa of pressure and shearing for N=1, N=5 and N=10 revolutions. The evolution of the

nanostructure was characterized by X-ray diffraction (XRD) and Vickers microhardness measurements. The

XRD results showed the presence of the α–Ti phase crystallographic planes (100), (101), (102) and (110),

as well as the (101) plane of the ω–Ti phase, the latter with increasing intensity with pressure and number

of revolutions of HPT. There was significant broadening of the α–Ti and ω–Ti phase peaks reflected on the

XRD profiles, which is consistent with grain refinement characteristic of the HPT process. Because of this,

a significant increase in the microhardness occurred after HPT processing, reaching a steady state after

N=10 rev at P=6 GPa, where a homogeneous distribution was achieved.

P16

SCiMAN2018 POSTER

Aging behavior and microstructure of pure Ti and Ti-6Al-7Nb processed by

High-Pressure Torsion

Jeimmy González-Masís1, Fernando A. Dittel-Meza1, Mauricio Castro1, Elena R. Ulate-Kolitsky1,

María Badilla-Sanchez1, Jorge M. Cubero-Sesin1, and Zenji Horita2,3

1Centro de Investigación y Extensión en Materiales (CIEMTEC), Escuela de Ciencia e Ingeniería

de los Materiales, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica 2Department of Materials Science and Engineering, Kyushu University, Fukuoka 819-0395,

Japan 3International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University,

Fukuoka 819-0395, Japan

In this research, characterization of commercially pure Ti and Ti-6Al-7Nb alloys processed by High-

Pressure Torsion (HPT) at 6 GPa, with different post-HPT aging conditions was achieved by scanning

electron microscopy (SEM), X-ray Diffraction (XRD) and Vickers microhardness evaluation. Hardness

increased with increasing the number of revolutions by HPT. A microstrain decrease was observed in the

aged Ti-6Al-7Nb samples with the increase of aging temperature. Furthermore, the hardness increased after

the aging treatment. In addition, XRD Rietveld refinement analysis determined phase fractions and

crystallite size in both alloys. Transmission electron microscopy (TEM) was used for the microstructural

and crystallographic characterization of the alloy of Ti-6Al-7Nb. These analyses by TEM were possible due

to the preparation of electron transparent samples by twin-jet electropolishing. It was determined that the

sample of Ti-6Al-7Nb alloy processed by HPT for N=20 revolutions had a highly deformed microstructure

with nanocrystalline domains present, with sizes below 20 nm.

P17

SCiMAN2018 POSTER

Photocatalytic activity of yellow and black TiO2-ZnO nanocomposite

produced by high-pressure torsion straining

Jacqueline Hidalgo Jiménez1, Qing Wang2, Kaveh Edalati2,3, Jorge M. Cubero-Sesín1, Yoshifumi

Ikoma2, Hadi Razavi-Khosroshahi4, Zenji Horita2

1Centro de Investigación y Extensión en Materiales (CIEMTEC), Escuela de Ciencia e Ingeniería

en Materiales, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica 2International Research Center on Giant Straining for Advanced Materials (IRC-GSAM),

Department of Materials Science and Engineering, Kyushu University, Japan 3International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University,

Japan 4Advanced Ceramic Research Center, Nagoya Institute of Technology, Japan

Photocatalysis of hydrogen is considered one of the most promising methods for hydrogen generation,

which involves three main steps: (1) a semiconductor absorbs photons of light and generates excited

electrons in the conduction band (CB) and holes in the valence band (VB), (2) excited carriers are transferred

to the semiconductor surface or recombined back into the material, (3) the electrons present on the surface

reduce the H+ ions to H2 while the holes will generate O2 (Sankir & Sankir, 2017). Given the importance of

renewable energies, in recent decades, several advances have been made in semiconductor nanomaterials,

such as TiO2, ZnO, among others, which are widely used in the field, opening a new era of clean energy

production. This research focuses specially on the photocatalysis method using TiO2-50mol. % ZnO

nanocomposite produced by High-Pressure Torsion (HPT), to study its effect on phase transformations,

optical properties of the mixture and its photocatalytic activity.

P18

SCiMAN2018 POSTER

Morphological image processing of nanoparticles’ TEM micrographs

Pablo Chaves1, Dionisio Gutiérrez1, Abraham Lopez1,2,

Ernesto Montero1 and Juan Carlos Rodríguez1,2

1Escuela de Física, Instituto Tecnológico de Costa Rica, Costa Rica

2Escuela de Ciencia e Ingeniería de Materiales, Instituto Tecnológico de Costa Rica

Image processing techniques have become a relevant method for different materials characterization. In the

synthesis of nanoparticles, it is important to determine the average size, its distribution and, in some cases,

the shapes it presents. The determination of some of its characteristics is usually done with specialized

techniques such as Z potential or transmission electron microscopy. The latter provides digital images that

can be processed to obtain detailed information. However, there are difficulties with the software and the

first results can be seen in figure 1. This research seeks to develop a method of image processing to quantify

the number, size and shape of silver nanoparticles, considering that these characteristics play an important

role to verify their correct synthesis.

Figure 1. Process of TEM micrographs analyzed by the software

P19

SCiMAN2018 POSTER

Study of modified phase change materials with hydrated particles for

electronic applications

Natalia Hernández-Montero1, Mavis Montero1, Oscar Andrey Herrera1 and Carolina Haug2

1Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica,

Costa Rica. 2Escuela de Ingeniería Química, Universidad de Costa Rica, Costa Rica

Electronic devices are currently designed to be more compact and lightweight. They are fabricated with

greater number of components to improve the efficiency, causing high temperatures. Phase change materials

(PCM) are a possible solution for this problem. However, they show some limitation, for instance low

thermal conductivity. The aim of this research is to analyze the effect of zirconium phosphate (ZrP) and

zeolite A particles in the thermal properties of PCMs (i.e. eicosane and lauric acid).

The zirconium phosphate was synthesized using reflux method from a precursor (i.e. ZrOCl28H2O) in acid

media. The zeolite A was prepared using Aluminum and Sodium Metasilicate in sodium hydroxide solution.

The resulting inorganic components were studied by X-ray Diffraction (DRX) and Infrared

spectrophotometry (FTIR), confirming the nature of the materials. Thermal degradation by

thermogravimetric analysis (TGA) and FTIR analyses suggested the presence of water. Therefore, the

surfaces of the materials were functionalized with octadecyltrichlorosilane, in order to enhance the

interaction with the organic compounds. The hydrophobic modification was analyzed using FTIR showing

the expected bands around 2850 cm-1 associated to the -CH stretching. In conclusion, these particles showed

promising properties to be used in the formulation of PCM composites. Heat capacity and thermal

conductivity are going be evaluated to confirm the potential application in electronic devices.

P20

SCiMAN2018 POSTER

Study of the evolution of oxidation in porous silicon surfaces by infrared

spectroscopy and contact angle

María Hernández L2, Yoselin Rojas F1,3, Arturo Ramírez-Porras1,2

1Centro de Investigación en Ciencia e Ingeniería de los Materiales (CICIMA), Universidad de

Costa Rica, San Pedro 11501, San José Costa Rica 2Escuela de Física, Universidad de Costa Rica, San Pedro 11501, San José, Costa Rica

3Escuela de Ingeniería Química, Universidad de Costa Rica, San Pedro 11501, San José, Costa

Rica

Porous silicon samples were made by an electrochemical etching process acting on nanocrystalline silicon

wafers. The samples were subject to two different oxidation processes and were studied by the infrared

spectroscopy method and determination of the contact angle. The first oxidation process involves increasing

in a controlled manner the sample’s temperature, while the second process consists in the sample’s

exposition by a long period of time at room temperature. It was finally found to be a correlation between

the contact angle and the oxidation phase in porous silicon samples.

P21

SCiMAN2018 POSTER

Synthesis and characterization of silver nanoparticles for analysis of biological

materials by SERS

Deyvis Alvarado Cerdas1,2, Ana Catalina Nororis Ortega1,2, Ernesto Montero Zeledón1

and Dionisio Gutiérrez Fallas1

1Escuela de Física, Instituto Tecnológico de Costa Rica, Costa Rica

2Escuela de Ciencia e Ingeniería de Materiales, Instituto Tecnológico de Costa Rica

Silver nanoparticles (AgNPs) were synthesized by chemical reduction of AgNO3, using sodium citrate and

sodium borohydride in aqueous solution. Adding a few drops of tannic acid to the solution allow to control

nanoparticles size. Optimal size of nanoparticles improve peaks intensity in Raman spectroscopy, through

the application of SERS method (Surface-Enhanced Raman Spectroscopy). The silver nanoparticles were

characterized by means of transmission electron microscopy (TEM) to verify their shape and size (Fig. 1).

Optical spectroscopy is used to corroborate some characteristics of AgNPs.

Figure 1. TEM of silver nanoparticles.

P22 SCiMAN2018 POSTER

Facile synthesis of fluorescent graphene quantum dots and its application as a

bio-imaging agent

Arianna Quesada-Ramírez1, Javier Villalobos2,3, Sergio Paniagua2,4, Jose R. Vega-Baudrit2,5

1Escuela de Física, Universidad de Costa Rica, Sede Rodrigo Facio, San José, Costa Rica

2Laboratorio Nacional de Nanotecnología, San José, Costa Rica 3Escuela de Química, Universidad de Costa Rica, Sede Rodrigo Facio, San José, Costa Rica

4Sección de Química, Universidad de Costa Rica, Sede Occidente, Alajuela, Costa Rica 5Escuela de Química, Universidad Nacional, Campus Omar Dengo, Heredia, Costa Rica

The development and study of graphene quantum dots (GQD) allows the implementation of novel type of

zero-dimensional luminescent nanomaterials. In this work we simplify a reported synthesis method for

GQDs from commercial graphite powder in which hydroxide ions exfoliate the graphite layers in an

organic solvent. This synthesis method offers a low-cost, eco-friendly and nontoxic alternative, which can

be used for several optical and electronic applications. Transmission electronic microscopy (TEM)

suggests that the resulting particle diameters are in the range of ca. 5 nm. The size population distribution

results in excitation wavelength-dependence color emission for our GQDs. We show their application to

image E. coli. in fluorescence microscopy, with color contrast comparable to a commercial dye.

P23

SCiMAN2018 POSTER

Theoretical study of electrical signals for the stimulation of biological tissues

Mauro Víquez1, Juan J. Montero-Rodríguez2, Ricardo Starbird3

1Área Académica de Ingeniería Mecatrónica, Instituto Tecnológico de Cosa Rica, Costa Rica

2Escuela de Ingeniería Electrónica, Instituto Tecnológico de Cosa Rica, Costa Rica 3Escuela de Química, Instituto Tecnológico de Cosa Rica, Costa Rica

The present work studies the characteristics of electrical signals for the stimulation of biological tissues.

There are more than nine different variables that play a role in the stimulation of tissues, and it is critical to

find out the ideal stimulus requires a detailed theoretical study. Therefore, signal waveforms such as

sinusoidal or square are used, with fixed frequencies or defined pulses, to optimize the stimulation of tissues

and enhance their growth rate. The possibility of using a paradigm of artificial intelligence, such as neural

networks, is explored, in order to model the organic systems in mathematical terms using synapse weights.

The network is trained with experimental data in order to obtain the ideal stimulation parameters.

P24

SCiMAN2018 POSTER

Generation of potential bactericidal surfaces from aluminum via anodization

Sergio Paniagua1, Esteban Rojas2, Javier Villalobos1, Gabriela Montes de Oca1, Reinaldo

Pereira1, Luis Carlos Murillo1, José Vega1

1Laboratorio Nacional de Nanotecnología (LANOTEC), Centro Nacional de Alta Tecnología

(CeNAT), San José, Costa Rica 2Escuela de Química, Universidad de Costa Rica, San José, Costa Rica

Due their potential application as bactericidal surfaces in the medical and food industry, the generation of

nanopillar and nanospikes gained attention in the recent years. The modified surface kills bacteria due

mechanicals mechanisms. These mechanisms offer the advantage of being more difficult for bacteria to

develop resistance compared to pharmaceutical alternatives. An important strategy to control the spread of

disease is to maintain surfaces clean to prevent secondary infection. Herein, we present the generation of

two nanostructures of aluminum oxide on an aluminum surface via soft anodization and acid etching. By

changing conditions nanowells or nanopillars can be obtained. Using the nanowell surface as a mold in a

replication process we were able to obtain nanopillars over an elastomer. We performed bactericidal tests

using E. coli over the modified aluminum surface by a colony count procedure and fluorescence microscopy.

The results obtained suggest that the surface is bactericidal and motivates further development of surface

modification procedures.

P25

SCiMAN2018 POSTER

Fabrication of microfluidic devices for the electrokinetic manipulation of

pathogenic samples

Juan Pablo Villalobos-Madrigal2,5, Alejandro Martínez-Brenes3,5, Rolando Duarte-Mejías1,

Gabriela González-Espinoza4, Norman Rojas-Campos4, Leonardo Lesser-Rojas1,5

1Escuela de Física, Universidad de Costa Rica, Costa Rica

2Escuela de Ingeniería Química, Universidad de Costa Rica, Costa Rica 3Escuela de Ciencia e Ingeniería de los Materiales, Instituto Tecnológico de Costa Rica, Costa

Rica 4Centro de Investigación en Enfermedades Tropicales, Escuela de Microbiología, Universidad de

Costa Rica, Costa Rica 5Laboratorio de Nano Bio Sistemas, Centro de Investigación en Ciencias Atómicas y

Moleculares, Universidad de Costa Rica, Costa Rica

This work demonstrates the methodology of fabrication of microfluidic devices with micron-sized

constrictions using a SU-8 silicon master mold, fabricated following a photolithography standard protocol,

for polydimethylsiloxane (PDMS) micromolding, utilized to study the electrokinetic response of injected

suspension of Brucella abortus, which is a type of Gram negative bacteria responsible of producing a disease

called Brucellosis. The third generation device allows to preconcentrate the bacteria in one constriction and

then mobilize it through side channels to another section where collection takes place.

Inert samples of Brucella abortus S-19 in aqueous solutions were previously stained using Texas Red to

observe its response in an inverted fluorescence microscope. 3D parts were created using free software and

then 3D-printed with PLA and ABS in order to use them to assemble the experimental setup in the

microscope´s platform. After an electric AC and/or DC field is applied to the bacterial solution in the

microfluidic device, combined electrokinetic phenomena such as electrophoresis, dielectrophoresis an

electroosmotic flows were observed around the constrictions and recorded with a high resolution CMOS

camera, and preliminary results are presented. Our further goal is to fully characterize the pathogen’s

response and enable its manipulation in such a scenario, in order to facilitate ways for target selection and

preconcentration of intracellular pathogens as well as sample preparation for metagenomics.

P26

SCiMAN2018 POSTER

Extraction and characterization of nanocellulose obtained from agro-

industrial wastes produced in Costa Rica

Galia Moreno1, José Vega1, Karla Ramírez2, Marianelly Esquivel2, Guillermo Jiménez2

1Laboratorio Nacional de Nanotecnología (LANOTEC-CeNAT), Pavas, San José, Costa Rica. 2Laboratorio de Polímeros (POLIUNA), Escuela de Química, Universidad Nacional, Heredia,

Costa Rica.

Considering the large amount of lignocellulosic material that is generated as a waste of agro-industrial

activities in Costa Rica, this research proposes to take advantage of this materials to extract nanocellulose.

The residues evaluated were pineapple, sugar cane and banana processing waste. From this raw material

were extracted cellulose, microcrystalline cellulose and nanocellulose. The nanocellulose extraction was

performed using mild hydrolysis with sulfuric acid (30% w/v) and a higher concentration of acid (60% w/v).

The raw material and the products extracted were characterized by Infrared Spectroscopy (FTIR), X-ray

diffraction (DRD) and thermogravimetric analysis (TGA). In addition, the nanocelluloses obtained were

studied by zeta potential, particle size analysis and transmission electron microscopy (TEM). The cellulose

nanowhiskers were obtained successfully with an average yield of 33%, applying mild acid treatment. The

banana and sugarcane rachis were the most promising materials, in terms of nanocellulose crystallinity and

amount extracted.

P27

SCiMAN2018 POSTER

Effect of the addition of nanocellulose obtained from the residue of pineapple

leaves in cementitious mixtures of hydraulic mortar

Esteban Solís Nicolaas1, José Roberto Vega Baudrit2, Einer Rodríguez Rojas1, 3, Luis Carlos

Meseguer Quesada1, 3

1Escuela de Ingeniería Civil, Facultad de Ingeniería, Universidad de Costa Rica, San José, Costa Rica

2Laboratorio Nacional de Nanotecnología (LANOTEC), San José, Costa Rica 3Laboratorio Nacional de Materiales y Modelos Estructurales (LanammeUCR), San José, Costa Rica

The contribution of nanotechnology in the new convergent technologies has been key in the synergy of

different sciences, engineering and industries, which generates the possibility of the improvement or

creation of new properties or new applications. The inclusion of natural fibers as an additive in hydraulic

concrete mixtures is of interest due to its abundance, for being an input from renewable sources and for its

potential contribution in the physical and mechanical properties in cementitious mixtures. There are

methods that allow obtaining a material at the nanoscopic level called nanocellulose from the cellulose that

is part of the structure or plant cell wall. In Costa Rica, the production and export of pineapple represents

one of the most important productive sectors for the country. The stubble of the pineapple crop represents

a biomass rich in cellulose that is commonly considered an agroindustrial waste or residue whose

management represents an expensive process and with possible adverse effects to the environment and

health.

The reuse and revaluation of this by-product is focused on the extraction of the lignocellulosic fiber

obtained from the leaves of the pineapple crop for the subsequent production of nanocellulose. The research

seeks mainly to evaluate possible variations in the properties of tensile strength, compression strength and

workability between the hydraulic cement mortar mixtures with different dosages of the product obtained

from the nanocellulose production process and the mixtures without addition. Mixtures were made with

four addition percentages in addition to the standard mixture (0%) with percentages in aqueous state with

respect to the weight of the cement for each additive obtained of 0.125%, 0.25%, 0.50% and 1% (0.013%,

0.025%, 0.05% and 0.1% dry weight respectively). In all the mixtures with some addition of nanocellulose,

percentage reduction values were obtained in the water / cement ratio for an adequate plastic consistency

in comparison to the standard mixture. All the mixtures with some addition of nanocellulose obtained values

of resistance to both tension and compression greater than the standard mixture.

P28 SCiMAN2018 POSTER

Restoring and conservation of Costa Rican cultural patrimony through

photogrammetry and additive manufacturing technologies

Carlos Villalobos1, Camilo Torres2, Luis Murillo2, Ana Eduarte3, José Vega-Baudrit1

1Laboratorio Nacional de Nanotecnología (LANOTEC), Centro Nacional de Alta Tecnología

(CeNAT), Costa Rica 2Mechatronics Engineering School, Universidad INVENIO, Costa Rica

3Museo Nacional de Costa Rica, Costa Rica

One of the most significant features of Costa Rica is its patrimony. There have been several findings in

recent years of different kind of artifacts and art pieces that have helped to obtain a better comprehension

of what Costa Rica was like several centuries ago. The National Museum of Costa Rica and LANOTEC

started to use photogrammetry to create CAD models of some archeological pieces. CAD models were used

to evaluate materials of an historical piece, simulate different conditions, and even to develop parts to help

its restoration using 3D printing technologies.

P29

SCiMAN2018 POSTER

First multispectral images in “La Poesía” and “La Danza”, paintings of

Vespasiano Bignami at National Theater of Costa Rica

Geraldine Conejo-Barboza1,2,3, Melissa Daniela Barrantes-Madrigal1,3

Carmen Marín-Cruz4, Eduardo Libby-Hernández1, Óscar-Andrey Herrera-Sancho3,5,6

1Escuela de Quimica, Universidad de Costa Rica, Costa Rica

2Instituto de Investigaciones en Arte, Universidad de Costa Rica, Costa Rica 3Centro de Investigacion en Ciencia e Ingenieria de Materiales, Universidad de Costa Rica, Costa

Rica 4Teatro Nacional de Costa Rica, Costa Rica

5Escuela de Fisica, Universidad de Costa Rica, Costa Rica 6Centro de Investigacion en Ciencias Atomicas, Nucleares y Moleculares, Universidad de Costa

Rica, Costa Rica

Materials characterization is crucial for understanding of ancient artistic production and for proper selection

of treatments to stabilize cultural heritage objects. In the case of paintings, these are one of the most complex

systems to analyze, given they are formed by several layers which in most cases are heterogenic and made

of organic and inorganic compounds (Berrie, 2012). In order to obtain information regarding the pigments

composition and the painting’ state of conservation, multispectral imaging (MSI) can be used as a

preliminary non-destructive method in order to address these issues (Barni, Pelagotti, & Piva, 2005). MSI

allows to analyze the behavior and response of the pigments interactions along these contrasting spectral

bands: Ultraviolet (UV) (360-400 nm), Visible (Vis) (400-780 nm), and Infrared (IR) (780-1100 nm). We

used the Vis and IR spectral region to study two paintings: La Poesía (9.83 x 5.13 m) and La Danza (9.83 x

5.13 m), of the Italian painter Vespasiano Bignami, located on the ceiling of the Foyer of the National

Theater of Costa Rica, both dated 1897. These paintings were made for the inauguration of the theater and

they represent two allegories of the art: Poetry and Dance, respectively. This study promotes through

scientific examination to observe the behavior of the pigments in the Vis and IR spectral region with the

aim to determinate the state of conservation of these paintings.

To apply the MSI for the paintings, we used a modified camera (Nikon D7200) with a Vis and IR filters

with two halogen lamps as source of light. Due to the aforementioned dimensions of the art work, it was

necessary to take forty eight shots for each painting. The shots taken for each painting were processed

through Adobe Lightroom and PTGui Pro. From the images it was possible to observe pigment detachments

in some regions of the paintings, changing in colors that can be possibly related to previews restorations

that started in the 1950’s, and with the IR it was possible to denote damages in the wood where the paintings

are attached in the ceiling. Also some pigments were absorbed in the IR, making them “invisible” to the

eye, this can give us a preliminary idea of the pigment composition.

The next experimental step is to characterize the two paintings with portable equipment such as: x-ray

fluorescence, infrared spectroscopy and Raman spectroscopy, to create a scientific file for each painting in

order to develop a conservation material that permit to keep the paintings in a good state of conservation

and therefore to protect the cultural heritage of Costa Rica.

Berrie, B. H. (2012). Rethinking the history of artists’ pigments through chemical analysis. Annual Review of Analytical Chemistry, 5, 441–59.

https://doi.org/10.1146/annurev-anchem-062011-143039

Barni, M., Pelagotti, A., & Piva, A. (2005). Image Processing for the Analysis and Conservation of Paintings: Opportunities and Challenges. IEEE

Signal Processing Magazine, (September), 141–144.

P30 SCiMAN2018 POSTER

Theory of Random Electric Field Instabilities in Relaxor Ferroelectrics

Jose Rafael Arce Gamboa1, Gian G. Guzmán-Verri1,2

1 Materials Research Science and Engineering Center, University of Costa Rica, San José, Costa

Rica 11501 2 Materials Science Division, Argonne National Laboratory, Lemont, Illinois, USA 60439

Relaxor ferroelectrics are complex oxide materials which are rather unique to study the effects of random

field disorder on phase transitions. [1] Unlike the mostly studied random field magnets where the order

parameter is uniaxial or isotropic, the polarization of typical ABO3 pervoskite relaxors lives in a cubic

environment. Moreover, the exchange interaction that drives the magnetic transition is short-ranged and

isotropic, while the relevant interaction in ferroelectrics (FEs) is the highly anisotropic and long-ranged

dipolar force. This puts relaxors in a different universality class from that of disordered magnets making the

standard model of random field disorder inadequate to describe their unusual properties. Here, we present

work in progress of a general framework of random electric field (REF) instabilities of the FE state in cubic

systems. We extend our previous work [2] to d-dimensional lattices and to include non-local cubic

anisotropies of the dipolar force. Our final goal is to determine the lower and upper critical dimensions, the

correlation functions of polarization, and dielectric response.

[1] R. A. Cowley et al., Adv. Phys. 60, 229 (2011).

[2] J. R. Arce-Gamboa and G. G. Guzmán-Verri, npj Quantum Materials 2, 28 (2017).

[3] V. Bovtun et al., Ferroelectrics 298, 23 (2004).