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 1 Terminology and definitions 2 Basic theory of fullerenes and nanotubes 3 Nanotube materials 4 Structural nanomaterials 5 Applications of nanomaterials 6 Briefly about manufacturing aspects 7 Scientific research of nanomaterials
Three different viewpoints Viewpoint 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.
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 Cs 3 C 60. 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.
Nanotubes The 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
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 MATERIAL ABBREVIATION PICTURE MAIN PROPERTY Carbon nanotubesC -Utilized to strengthen different composite materials Boron-based nanotubes B and BN -Superconductors in high temperatures -Chemical resistant coatings Silicon nanotubesSi -Improved energy efficiency of batteries Titanium nanotubes Ti - Small sized hydrogen sensors Manganese oxide nanotubes MnO 2 -Improved energy efficiency of batteries Molybdenum- Sulfur-Iodine nanotubes MoSI -Utilized in lubricants Polyaniline nanotubes PAni-Electrically conductive synthetic polymers
Structural nanomaterials The main material group in engineering is nanocomposites. Main nanocomposites are divided into three groups: Nanoparticle applications Nanofibre 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.
Nanocomposites By 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, Ag Metal oxides such as ZnO, Al 2 O 3,CaCO 3, TiO 2 Non-metallic oxides e.g. SiO 2 Other. e.g. SiC
How to establish the required mechanical properties? The observations should be made on three levels: Bonding properties of different atoms and molecules Adjusted properties of the selected nanotubes Matrix + reinforcement Properties of the nano- composite
E SWNT E MWNT ~1000 GPa (SWNT) ~1200 GPa (MWNT) Ultimate tensile strength ~ 100 GPa Heat conductivity 2000 W/m/K Density ρ SWNT ρ MWNT 1300 kg/cm 3 1400 kg/cm 3 Properties of carbon nanotubes
Bonding between the nanotubes Purposely 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 Stress [MPa]
Effects of the carbon nanotube content on composite’s modulus of elasticity Polymer matrix Polymer’s E [Mpa] Nanotubes [Weigth %] Composite’s E [Mpa] Increase of E PS240053500× ~ 1.5 MEMA70812340× ~ 3.3
Failure modes of nanofibre reinforced composites
Carbon fibreMatrix Carbon nanotube reinforced matrix Unreinforced ”empty” space between the fibres IMPROVED STENGTH AND DUCTILITY
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 matrix Increased: Strength Ductility Rigidity (depends on geometry) Dimensional stability Heat resistance Chemical resistance Possibilities 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)
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
MANUFATCURING OF NANOTUBES, - FIBERS AND PARTICLES MANUFACTURING OF THE PRODUCT WHOLE GEOMETRY SURFACE What are we actually manufacturing? RAW MATERIAL = NANOMATERIAL
DIMENSIONS AND OTHER PROPERTIES DIMENSIONS AND OTHER PROPERTIES RAW MATERIALS MANUFACTURING PROCESSES PHASES 1 nano dimension: Coating 2 nano dimensions: Wires 3 nano dimensions: Particles Solid Composite matrix Liquid Gas-phase reaction Liquid-phase reaction Mechanical manufacturing Carbon-based Metal-based Polymer-based Composite s !
Some manufacturing methods Gas 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
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 WORKCONSUMER’S EXPOSURE HEALTHY RISKS