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
SCiMAN2018 POSTER
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).
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