Exploring the Nanoparticle Potential
The total world market for nanoparticulate materials (materials between 1 and 100 nanometers in size) reached $492.5 million in 2000 and is expected to grow to $900.1 million in 2005, according to a presentation by Dr. Mindy N. Rittner, senior industry analyst for BCC. Electronic, magnetic and optoelectronic applications are expected to continue generating the largest demand, with an anticipated 74.2% market share by 2005. Biomedical, pharmaceutical and cosmetic applications are expected to hold 16.1% of the market in 2005; while energy, catalytic and structural applications are expected to hold 9.8%.
Currently, the most commercially important nanoparticulate materials are simple metal oxides, such as silica (SiO2), titania (TiO2), alumina (Al2O3), iron oxide (Fe3O4 and Fe2O3), zinc oxide (ZnO), ceria (CeO2) and zirconia (ZrO2). Also of increasing importance are the mixed oxides, such as indium-tin oxide (In2O3-SnO2 or ITO) and antimony-tin oxide (ATO), as well as titanates, particularly barium titanate (BaTiO3). Other types of nanoparticles, including various complex oxides, metals, semiconductors and nonoxide ceramics, such as tungsten carbide (WC), are also under development and are available from some companies in primarily small or pilot-scale quantities.
Inframat Corp. in Farmington, Conn., is developing the next generation of a nanostructured hydroxyapatite (n-HA) coating for artificial bone implants using a room-temperature electrophoretic deposition process. According to Dr. Danny Xiao, vice president of R&D, current artificial implants use micrometer-sized HA particles coated on metal substrates using thermal spray processes. The high-temperature thermal spray process often causes HA coating delamination from implants in service due to the dissolution of the amorphous phase. Inframat’s room-temperature electrophoretic deposition process overcomes this difficulty. The nanocoatings are obtained at ambient temperature, thus mimicking the functional properties of the human body. Additionally, the coatings offer significantly increased coating-to-substrate adhesion, an extended lifetime for the artificial implants, and a lower-cost fabrication process.
Recent breakthroughs in advanced nanomaterials have also provided new opportunities to develop high-power and high-energy batteries for pure electric and hybrid electric vehicles. According to Dr. G. Abbas Nazri, staff research scientist for General Motors R&D and Planning Center in Warren, Mich., the unusual catalytic properties of nanoparticles embedded in a suitable matrix has provided a non-traditional electrode assembly that can satisfy the energy and power requirements of electric vehicles. Future batteries based on nanomaterials are expected to satisfy the long travel range of 300 miles, enabling them to fully substitute internal combustion vehicles.
Producing large quantities of nanoparticles with identical properties cheaply and reliably, however, remains a challenge. According to Xiangdong Feng of Ferro Corp., Cleveland, Ohio, nanoparticles represent not only a size concept, but, more importantly, a state of matter that displays new physical, chemical and biological properties when compared with the bulk materials.
Still, according to Dr. Don Freed, vice president of business development for Nanophase Technologies Corp., Romeoville, Ill., enormous potential for nanoparticle technology does exist, and increasing demand will help both suppliers and end users overcome the challenges. It’s just a matter of time.