Nanomaterials are simply materials having dimensions between 1 nm to 100 nm. They can be any type of material that is manipulated at an atomic or molecular level. There is a lot of interest in the scientific community to synthesize materials at nanoscale and use them for novel purposes. Nanomaterials are any type of material that is manipulated at an atomic or molecular level. Quantum dots, Carbon nanotubes and graphene have diameters of less than 100 nanometers. Materials with structure at the nanoscale often have unique optical, electronic, or mechanical properties.
Nanomaterials exist in many forms like free nanoparticles with varying shapes, structured thin films with different aspect ratios, nanotubes which can be single walled or multi-walled, nanowires, nanoshells which can be hollow as well, nanocomposites, aggregates, crystalline or amorphous, micelles, dendrimers, bionanomaterials, aerosols, emulsions etc. Classification of the nanomaterials can be done broadly on the basis of nature of origin, dimensions, composition, phase and manufacturing process. At the most basic level, nature has created a number of inorganic and organic nanomaterials in the forms of nanotubes, nanodots, nanowires, and even nanomachines.
Nanomaterials available in market
- Nanoceramics are available commercially in the form of dry powders or liquid dispersions.
- The most commercially important nanoceramic materials are simple metal oxides, silica (SiO2), titania (TiO2), alumina (Al2O3), iron oxide Fe3O4, Fe2O3), zinc oxide (ZnO), ceria (CeO2) and zirconia (ZrO2).
- Silica and iron oxide nanoparticles have a commercial history spanning half a century or more.
- Mixed oxides and titanates:
– indium-tin oxide (In2O3-SnO2 or ITO)
– antimony-tin oxide (ATO),
– barium titanate (BaTiO3).
- Nanocrystalline titania, zinc oxide, ceria, ITO, and other oxides have more recently entered the marketplace.
- Nonoxide ceramics, such as tungsten carbide (WC) – Under development and available in small or pilot-scale quantities.
- Except semiconducting oxides such as titania and ITO, semiconductor nanocrystals are not yet used in large-scale commercial applications; the technology to produce and utilize nanocrystalline semiconductors, often called quantum dots, is relatively new and rapidly developing.
- Two main types of Carbon nanotubes: Single Wall Carbon Nanotubes (SWCNT) and Multi Wall Carbon Nanotubes (MWCNT)
- SWCNT – Research materials with limited applications, large future potential
- MWCNT – Use in thermoplastic nanocomposites.