The emerging field of nanoscale science engineering and technology is leading to remarkable developments in materials science and engineering. The field of material science has been transformed so that the relationship between the structure of a material and its properties may be controlled to fit the specific needs of a specific end use.
Nanotechnology Changing Conventional Technologies
Conventional technologies have been dramatically influenced by nanotechnology. For instance, coating technology is now being strongly influenced by nanotechnology. Metallic stainless steels coated using nanocrystalline powders possess increased hardness when compared with conventional coatings, despite increased porosity. Novel tungsten carbide-cobalt coatings produced from nanostructures powder have shown increased bending strength. Nanostructured ceramic coatings such as WC, Cr3C2, Al2O3-TiO2 and ZrO2 have been successfully applied.
Catalysis is the most powerful technology of our times as it enables the production of a wide range of materials and fuels, and is vital in controlling emission and pollution. It is expected that nanotechnology would evolve methods of producing spectacular catalysts with a better understanding of the structure of nanoparticles with their reactivity. Nanometal oxides such as titanium dioxide and cerium oxide have been used successfully as catalysts because of their increased reactivity and smaller particle size (1-10 nm) and increased resistance to sintering. Taking advantage of getting out of the quantum effect regime at particle size below 5 nm, remarkable coating properties such as anti-scratch, anti-wear, self-cleaning have been obtained without affecting clarity. Nano-based coating has been used as friendly water-borne coating in automotive applications.
Ink Jet Printing
Because of the small particle size, large active surface, greater chemical activity and greater solubility better ink jet printers can be made for printing. Such ink jet printers are now being produced in which the ink dries instantaneously. An ink manufacturer has produced non-porous aluminum hydroxide for coating ink jet tapes which dry instantly. Fine grain size powders are being used to produce denser and new lightweight high strength composite materials.
Montmorillionate, saponite and synthetic mica have been successfully exploited with advantage of improved stiffness, strength, toughness and stability. Closite and nanomer are commercially available. One of the amazing feats of using nanocomposites in automotive industry is shown by the General Motors which produces 245 tons/year of montmorillionate reinforced nylon 6 for use as engine cover. Montmorillionate is an aluminosilicate comprising one central aluminum layer between two silicate layers which exfoliates at 1 nm thick platelets and a weight reduction of 7% is achieved. The above example represents the acceptance of nanotechnology in the automotive industry. The aerospace, defense and biomedical industries are the potential beneficiaries of these materials.
A uniform and titanium dioxide nanoparticle on steels has been recently developed using sol-gel technique and dip coating technology. It has been shown that the super hydrophobic coating on 316L exhibits an excellent resistance to corrosion in chloride containing solutions at room temperature. Silicon based nanocomposites containing titanium dioxide using high energy mechanical milling have been synthesized with success for lithium ion battery.
Economical Production of Nanomaterials
The widespread use of nanocrystalline materials would require economical production of materials in large quantities which would require the improvements in the existing methods of synthesis and development of new and economical methods. Despite the increased impact of nanotechnology on cutting edge industrial applications, pressure groups, technical writers and industrialists have circulated misconceptions, hypes and fears surrounding nanotechnology. The hypes such as self-replicating nanorobots, immortal man, readymade body shops and non-injury no death no pain drops have mixed up the facts with fiction and diluted the realities and achievements of nanotechnology. There are also concerns about the greater divide between the rich and poor countries with greater dominance of advanced nations and extra financial burden on the poor countries to pool up their resources for the growth of nanotechnology.
Social, Moral and Ethical Issues
Despite the social, moral and ethical issues, nanotechnology has come to stay as a dominant force encompassing computers, medicines, machining economics, environmental and many other facets of human life. There is a pressing demand to equip the future material scientists and engineers with the basic knowledge of nanotechnology starting at high school level and expansion of undergraduate and graduate degree programs in nanotechnology. More consideration is to be given to alleviate the fears of poor nations and the impact of nanotechnology on their economics and material resources. With explosion of interest by engineers and scientists, and generous funding, nanotechnology is expected to be one of the top cutting edge technologies of the next century.
Is nanoutopia hype, a super hype, a dream or a viable possibility? As evidence shows, it is the transformation of a dream to reality. However, it is liable to create a plethora of social and moral implications in future. It is therefore important to be aware of the intrinsic danger of this technology and plan a future strategy for security and control.