BK50A2700 Selection Criteria of Structural Materials

Lesson 92014

Selection of nanomaterials

Lesson 92014

The goal of this lesson

Our goal is, that after this lesson, students are able to recognize the main groups of nanomaterials with their typical properties and are able to name the most important aspects to adjust material properties by utilizing nanotechnology.

Outline

Outline1 Terminology and definitions2 Basic theory of fullerenes and nanotubes3 Nanotube materials4 Structural nanomaterials5 Applications of nanomaterials 6 Briefly about manufacturing aspects7 Scientific research of nanomaterials

Terminology and definitions

Three different viewpointsViewpoint based

on the observations of atomic or molecular level.

Viewpoint focused to applications of materials, which are based on utilization of nanoparticles, nanopowders or nanofibres.

Viewpoint of nanomechanisms used in nanosystems and nanomachines.

Dimensions

3 nanodimensions < 100nm Particles

2 nanodimensions < 100nm Tubes, fibres, wires

1 nanodimension < 100nm Layers, films.,coatings

States

One solid state Crystal structured, amorphous structures

Several solid states Matrix composites

Several states Cell structures, liguid states

Manufacturing

Gas phase reaction CVD- or plasma coating

Liquid phase reaction Solid-gel techniq

Mechanic Grinding, elastic deformation

Materials

Carbon based Fullerens, carbon nanotubes

Metal based Silver, gold, metal oxides

Polymer based PEA, PP, PA

Composites

Viewpoint of (structural) material selection

Basic theory of fullerenes and nanotubes

The development of nanomaterials has started from recognizing the different states of carbon and utilizing their different (material) properties

Different states of carbon: Diamond, Graphite and graphene,Fullerene(s), Amorphous carbon, Carbon nanotube

Diamond• Each carbon atom has the bond with

four adjacent carbon atoms (strong 3D-net)

Graphite• A layered structure, in which carbon

atoms have bonds only on one atomic plane

• Graphene is one of these layers

Fullerene• A spherical-shaped construction of 60

carbon atoms

Basic form is the spherical-shaped construction of 60 carbon atoms The fullerene can encapsulate different atoms inside its hollow core, eg. a

nitrogen atom. The structure is formed of several fullerenes, there is a hollow space also

between each fullerene, into which different atoms can be positioned.The control of these types of encapsulations and positions

including the bonds of different atoms are in key-role in nanotechnology.

Fullerenes

The schematic illustration of a cesium-fullerene-construction Cs3C60.

By controlling the positions of cesium atoms between the fullerenes it is possible to produce the crystal structure which reacts to the changes of external pressure or temperature.

NanotubesThe utilization of nanotubes to develop better constructional

materials requires knowledge about different structures with different properties of nanotubes made of different materials.

E.g. carbon nanotubes can be applied as nanofilters in nuclear technology by utilizing them to absorb and filter Tritium from the cooling water.

The knowledge of these kinds of properties is in key-role in nanotechnology.

• Dimension• Diameter• Length

• Different twisted forms• Bundles of nanotubes

How to adjust the properties of (carbon) nanotubes?

In theory the nanotubes could be regarded as rolled graphene sheets.

These sheets can be tightened (rolled) into different form, which have different (mechanical) properties.

The names for these twisted forms are:”Zig-zag”, ”Armchair” and ”Chiral”.

In practice the problem is to separate different form from each other during the manufacturing process.

Zig-Zag

Armchair

Chiral

DIFFERENT TWISTED FORMS OF THE CARBON NANOTUBE

Number of walls in the nanotube

Abbreviations:SWNT, DWNT and MWNT)

”VISIONS” OF Y-, W- AND STAR-BRANCHED NANOTUBE STRUCTURES

Branched nanotube structures

Type of the naotube

Property ↓

Single-Wall Carbon

Nanotubes (SWNT)

Double-Wall Carbon

Nanotubes (DWNT)

Multi-Wall Carbon

Nanotubes (MWNT)

Diameter ~ 1.3 nm ~ 4 nm 10-100 nm Length 0.5 ~ 40 um 0.5 ~ 40 um 0.5 ~ 40 um

Direction of the twist

The regular forms of atomic structures in nanotube walls can be disturbed purposely in different ways…

Deviations of the symmetric hexagonic positioning of the carbon atoms

SYMMETRIC POSITIONING OF CARBON ATOMS ON THE WALL OF A CARBON NANOTUBE

ARRANGED REGULAR DEVIATIONS OF CARBON ATOMS’ POSITIONING

Mechanical, thermal and electrical properties of carbon nanotubes can be tuned by arranging regular deviations of the symmetric hexagonic positioning of the carbon atoms.

Nanotube materials

MATERIALS:C-nanotubesBN-nanotubesMoSI-nanotubesSi-nanotubesMnO2-nanotubesTi-nanotubesPAni-nanotubes

DIAMETER TWISTED FORMS DIRECTION OF THE TWIST

BUNDLES OF NANOTUBES NUMBER OF WALLS

NANOTUBES

Zig-Zag

Armchair

Chiral

3 walls 2 walls 1 wall TWNT DWNT SWNT (MWNT = multi-wall nanotube)

DEVIATIONS OF CARBON ATOMS’ POSITIONING

BRANCHING

Industrial nanotube materialsCarbon nanotubesBoron-based nanotubesSilicon nanotubesTitanium nanotubesManganese oxide nanotubesMolybdenum-Sulfur-Iodine nanotubePolyaniline nanotubes

NANOTUBE MATERIAL

ABBREVIATION

PICTURE MAIN PROPERTY

Carbon nanotubes

C - Utilized to strengthen different composite materials

Boron-based nanotubes

B and BN - Superconductors in high temperatures

- Chemical resistant coatings

Silicon nanotubes

Si - Improved energy efficiency of batteries

Titanium nanotubes

Ti - Small sized hydrogen sensors

Manganese oxide nanotubes

MnO2- Improved energy efficiency of

batteries

Molybdenum-Sulfur-Iodine nanotubes

MoSI - Utilized in lubricants

Polyaniline nanotubes

PAni - Electrically conductive synthetic polymers

Structural nanomaterials

Structural nanomaterialsThe main material group in engineering is

nanocomposites.Main nanocomposites are divided into three

groups: Nanoparticle applicationsNanofibre applications Nanocoating applications

In addition to these remarkable number of engineering applications are based on the utilization of nanowires or -rods made of Silver, Gold or Palladium.

NanocompositesBy utilizing nano technology it is possible

to improve the properties of

polymer, ceramic and metal

matrix composites.

It is also possible to form nano-nano-composites.

Examples: polymer matrix and inorganic nanoparticles

Typical polymer matrix materials:Polyamide (PA) Polypropylene (PP) Polystyrene (PS) Polyethyleneakrylate (PEA)

Typical nanoparticles are made of:Metals such as Al, Fe, Au, AgMetal oxides such as ZnO, Al2O3,CaCO3, TiO2

Non-metallic oxides e.g. SiO2 Other. e.g. SiC

Nano-nano-composites

Example:

How to establish the required mechanical properties?

The observations should be made on three levels:

Bonding propertiesof different atomsand molecules

Adjusted properties ofthe selected nanotubes

Matrix + reinforcementProperties of the nano-composite

ESWNT

EMWNT

~1000 GPa (SWNT)~1200 GPa (MWNT)

Ultimate tensile strength

~ 100 GPa

Heat conductivity

2000 W/m/K

Density ρSWNT

ρMWNT

1300 kg/cm3

1400 kg/cm3

Properties of carbon nanotubes

Bonding between the nanotubesPurposely made deviations of carbon atoms’

positioning can be utilized to ensure the joints inside the bundles of nanotube groups.

!

Effects of nanotubes diameter and twisted forms on modulus of elasticity

Effects of nanofibres on stress-strain-curve

Pure epoxy

0.3 % added nanofibres

Strain

Str

ess

[MP

a]

Effects of the carbon nanotube content on composite’s modulus of elasticity

Polymer matrix

Polymer’sE [Mpa]

Nanotubes[Weigth %]

Composite’s E [Mpa]

Increase of E

PS 2400 5 3500 × ~ 1.5

MEMA 708 1 2340 × ~ 3.3

Failure modes of nanofibre reinforced composites

Carbon fibre Matrix

Carbon nanotube reinforced matrix

Unreinforced ”empty” space between the fibres

IMPROVEDSTENGTH

ANDDUCTILITY

Carbon nanotube Graphite fibres Kevlar-fibres Steel

Tensile strength 200 5 3 1.2

3.16

31.62

316.23

TENSILE STRENGTH

TE

NS

ILE

ST

RE

NG

TH

[M

Pa

]

Carbon nanotube

Carbon fibre Aluminium alloy Steel

Relative strength 4760 280 13 10

250

750

1250

1750

2250

2750

3250

3750

4250

4750

Relative strength

UL

TIM

AT

E T

EN

SIL

E S

TR

EN

GT

H/

DE

NS

ITY

Nanoparticles can be used to improve the ductility of ceramics.

Nanoparticles increase also the hardness and wear resistance of ceramics.

Effects on the properties of ceramics

What are the reasonable values for the ratios of

strength/ rigidity, strength/ density and rigidity/ weight

of a handlebars in a bicycle?

Effects of the nano reinforcement on the properties of polymer matrixIncreased:

StrengthDuctilityRigidity (depends on geometry)Dimensional stabilityHeat resistanceChemical resistancePossibilities to produce adjusted material properties

Decreased:Viscosity

difficult for extrusion

Quality of the properties due to Different portion of nanoparticles due to different shapes of the product Anisotropic properties due to nanofibres directions Possible unwanted layered structure

Appearance Unwanted colours (typically black or gray)

Applications of nanomaterials

APPLICATIONS IN ELECTRONICS

Nanomaterials in batteries

Touch screen of mobile phones

APPLICATIONS IN ENERGY TECHNOLOGY

Solar panels

APPLICATIONS IN SPACE TECHNOLOGY

Satellites

ENVIRONMENTAL APPLICATIONS

The potential impact areas for nanotechnology in water applications are divided into three categories:1. Treatment and remediation, 2. Sensing and detection 3. Pollution prevention

APPLICATIONS IN CHEMISTRY

MEDICINE

FOOD INDUSTRY

Carbon nanotubes are utilized e.g. in badminton rackets

SPORTS EQUIPMENT

CUTTING TOOLS

MILITARY APPLICATIONS

ANTI-SLIPPERY COATINGS

Briefly about the manufacturing aspects

MANUFATCURING OF

NANOTUBES, -FIBERS AND PARTICLES

MANUFACTURING OF

THE PRODUCT

WHOLE GEOMETRY

SURFACE

What are we actually manufacturing?

RAW MATERIAL =

NANOMATERIAL

DIMENSIONSAND OTHERPROPERTIES

RAW MATERIALSMANUFACTURING

PROCESSES

PHASES

1 nano dimension: Coating 2 nano dimensions: Wires 3 nano dimensions: Particles

SolidComposite matrixLiquid

Gas-phase reactionLiquid-phase reactionMechanical manufacturing

Carbon-basedMetal-basedPolymer-basedComposites

!

Some manufacturing methodsGas phase synthesis to manufacture

nanoparticles or nanotubes for further use. Vapourisation with plasma, laser or chemical methods

Sol-gel-synthesis to manufacture several types of products and semi-products of nanobased materials.

Different coating methods to manufacture the nanoscaled surface layer of the product CVD -coating (Chemical Vapor Deposition) HVOF -coating (High Velocity Oxy Fuel).

Mechanical grinding and alloying to manufacture nanoscaled powders for sintering and pressing processes.

Sol-gel-method

Kuidun muodostus

MAIN PRODUCTSRAW MATERIAL OPTIONAL PROCESSES

Scientific research of nanomaterials

Research interest areas (scientific vs. industrial topics)

EXPOSURE TO NANOMATERIALS

PRODUCTION PROCESSES OF

NANOMATERIALS

PRODUCTION OF PRODUCTS MADE

OF NANOMATERIALS

RECYCLING PROCESSES OF

NANOMATERIALS

RE-USE OF NANOMATERIALS

EXPOSURE DURING THE USE

ENVIRONMENTAL EXPOSURE

EXPOSURE DURING WORK CONSUMER’S EXPOSURE

HEALTHYRISKS