Ann M. Thayer
C&EN Houston

Nanoscale materials are at least a 100-year-old industry. Materials as mundane as the fillers in automotive tires are 10- to 500-nm particles of carbon black, graded by size and selling for less than 40 cents per lb. Venerable chemical companies such as Cabot and Degussa-Hüls are the leading producers in the mature 6 million-ton-per-year global carbon black market for tires.

But small companies, predicated on scientific developments in the past decade and spurred on by the U.S. government's nanotechnology initiative , have been coming out of the woodwork. Venture capitalists' interest is being piqued by the buzz about nanotechnology. The prefix "nano" is almost as ubiquitous as the ".com" suffix. And it's difficult to separate the reality from the hype because many are privately held firms, with university origins, about which few specifics are available.

Plans for commercializing nanotechnology range from the development of nanoscale electronics and computing applications to the creation of molecular machines and manufacturing capabilities at the nanometer level. But most companies fall in the materials area, producing organic, inorganic, and metal nanomaterials. Many have limited production capabilities for research-scale or maybe development-scale quantities.

However, they are working with partners or alone to develop new applications for nanomaterials. These applications vary from use in polymers, batteries, electronics, cosmetics, sensors, fuel cells, and catalysis to coatings on metals and computer screens and other displays. Other companies are making nanoparticles for biological applications such as drug delivery, discovery, screening, and diagnostics.

Polymers with nanosized reinforcing particles are poised for commercialization, according to a study by market research firm Bins & Associates , Sheboygan, Wis. Automotive and packaging applications will be the first to benefit, predicts company President Peter Bins.

Compared with traditional fillers, nanocomposites may offer enhanced physical features--such as increased stiffness, strength, barrier properties, and heat resistance, without loss of impact strength and with improved aesthetics--in a very broad range of common thermoplastics and thermosets. And because particle sizes are on the order of the wavelengths of visible light, they do not change optical properties such as transparency.

"Most applications are developmental, and the current market is very small, confined primarily to a few nylon-based nanocomposites," Bins explains. "But the future potential is tremendous, on the order of millions of tons by 2010." Nanosized reinforcements will account for only 3 to 5% of this total, or tens of thousands of tons, since optimum benefits are achieved at this low level of incorporation.

The most cost-effective nanomaterials available are layered, often chemically modified, clays consisting of nanometer-thick platelets of up to 1,000 nm in diameter. "Current global demand for nanoclay reinforcements may be only a few thousand tons, a small fraction of the supply capacity already in place," Bins says. "Because of this, current prices are rather high, probably in the range of $5,000 to $10,000 per ton, but future prices should be well below this level as demand increases." By 2010, he estimates that global markets for nanoclays will be in the hundreds of millions of dollars, with nanocomposite markets valued 15 to 30 times higher.

Two companies active in nanoclay development and commercialization are Nanocor, an Arlington Heights, Ill.-based subsidiary of Amcol International, and Southern Clay Products, a Gonzales, Texas-based subsidiary of the U.K.'s Laporte. Despite the positive market outlook for nanoclays, Nanocor is up for sale as Amcol seeks "strategic alternatives" for its businesses, and Southern Clay is among operations being sold by Laporte as it focuses on specialty organics.

Nanophase Technologies uses plasma vapor synthesis to produce inorganic nanocrystalline materials.

Nanocor has patented technology and has said it's gearing up to produce as much as 20,000 tons per year. The five-year-old company has development agreements with Bayer for nylon nanocomposites and Eastman for polyethylene terephthalate packaging applications. It also has a license from Toyota, which developed products in the late 1980s, for producing nylon nanocomposites. Likewise, Southern Clay has provided nanoclays to a joint development project with General Motors and Montell to produce thermoplastic nanocomposites for use in auto parts.

Most major polymer companies are exploring nanocomposite technologies. Plastics compounder RTP, Winona, Minn., has commercialized nylon nanocomposites for film and sheet applications, and Triton Systems, Chelmsford, Mass., works in packaging. Dow Chemical and Magna International are developing production technology for automotive applications under the government's Advanced Technology Program. In Japan, Ube Industries and Unitika are commercial producers of nylon nanocomposites.

Hybrid Plastics, Fountain Valley, Calif., has a technology for producing polyhedral oligomeric silsesquioxanes--essentially chemically modified nanoscale particles of silica--that can be incorporated into plastics. The company says it can manufacture bulk amounts and is collaborating with plastics producers and users, including the Air Force.

"The first 10 years of nanocomposite development were filled with frustrations: the demonstration of fantastic performance characteristics and yet inconsistent performance replication, intractable technical barriers, and high costs to achieve good exfoliation [delamination and dispersion] of the nanosized reinforcements," Bins explains.

There are now "few further technical barriers to rapid commercialization," with reports that "nanocomposite trials by technology leaders have met full performance expectations," he continues. "Several large applications are close to commercialization, meaning they will hit the market within the next few months."

Fullerenes and nanotubes

Carbon nanotube polymer composites are gaining interest as well. According to Principia Partners, Exton, Pa., the market for these composites will reach about 80,000 tons by 2009. The market research firm says interest in nanocomposites is "keen, but uncertain," due to embryonic process and product development and economic questions.

RTP offers nanotube-filled polymer compounds--based on nylon, polycarbonate, and other engineering polymers--that maintain the resins' key physical properties but have uniform surface conductivity. These materials avoid static buildup and are suited for electronic wafer processing, disk drive components, and clean room applications, RTP says, in addition to automotive applications where static discharge is important.

Since 1990, Materials & Electrochemical Research (MER), Tucson, has managed rights to fullerene production technology based on work by physics professor Donald R. Huffman at the University of Arizona and Wolfgang Krätschmer at Max Planck Institute for Nuclear Physics, in Heidelberg, Germany. MER has bulk production capabilities of up to 30 kg per day, a development joint venture with Mitsubishi, and has licensed production technology to Honjo Chemicals in Japan.

"There has been a lot of talk about fullerenes and nanotubes, but nothing yet uses any large amounts of them commercially," says James C. Withers, MER's chief executive officer. "Applications are emerging that look like they will reach commercialization and use large quantities. An area that appears to have great promise is in electrodes, primarily in the battery industry." Another near-term application is using nanotubes in organic fibers, such as nylon and polyesters, where a very small amount increases fiber strength and stiffness and also makes them conductive.

Hyperion Catalysis, in Cambridge, Mass., produces carbon nanotubes that it calls graphite fibrils. The fibrils can be used as a conductive filler in plastics and coatings and, after functionalization, as a catalyst support. GE Plastics has used Hyperion's technology to introduce a conductive resin for electrostatically painted molded parts, such as for cars, and for business equipment, such as computers, to avoid electrostatic buildup.

Rice University , home to professor of chemistry and physics Richard E. Smalley , who won the 1996 Nobel Prize in Chemistry for his work on fullerenes, recently gave Houston-based Carbon Nanotechnologies exclusive license to its carbon nanotube technology. Formed this year by Smalley, who is director of Rice's Center for Nanoscale Science & Technology, and former Lyondell Chemical CEO Bob G. Gower, the company says it has the process to make "substantial quantities that will be economically feasible for many applications." Partnership talks are under way, it adds, with promising applications in electromagnetic shielding, flat-panel displays, nanoelectronics, and composites.

However, Withers says, most sales still are to the research market. But, he notes, "people used to buy milligram quantities, then they started buying gram quantities, and now they buy kilograms." Depending on the purity and special attributes such as isotopic enrichment, fullerenes can cost dollars per milligram or per gram. Likewise, single- or multiwall nanotubes can cost from tens to hundreds of dollars per gram. "Our long-term projection, if you make large quantities," he adds, "is that they won't be substantially more expensive than carbon black."

Biological applications

Still on the pricey side are derivatized fullerenes, which are being studied in biological applications. MER, for example, sells a range of fullerenes with organic functional groups. Other small companies are working with nanoparticles based on other materials as genetic or biological probes in drug discovery, screening, and diagnostics. And others are looking at drug delivery.

	Semiconductor nanoparticles, or quantum dots, of different sizes luminesce when excited by a single light source. [Quantum Dot photo]

One of the most straightforward approaches is nanocrystalline drugs. NanoSystems, owned by Irish drug company Elan, uses its technology for drugs that have poor water solubility, stabilizing the drug nanoparticles with polymers on their surfaces. Alachua, Fla.-based Nanosphere has a related technology--applicable, but not limited to, controlled-release drugs--that applies polymer, ceramic, metal, or biomaterial "nanosphere" coatings on particles.

Quantum Dot, Hayward, Calif., makes semiconductor-based nanoparticles. The luminescent dots have hydrophillic surfaces so they can work in aqueous solution. They can be used with almost any optical detection method and will compete with traditional methods such as dyes. "The quantum dots can be attached to DNA, to proteins, to various sorts of biological affinity molecules such as antibodies, or put within different sorts of microscopic carrier particles for colorimetric bar coding purposes," says Joel F. Martin, Quantum Dot's president and CEO.

Martin sees an "almost endless string of applications in the biological arena" and a huge potential market. The two-year-old company intends to be a developer, manufacturer, and marketer of biological assays. It has been focusing on technology development with partners, product optimization, and manufacturing issues. Only small amounts of material are needed, and Martin believes that the company eventually will be able to produce quantum dots at "extremely large scale--kilogram quantities," and will be shipping products by mid-2001.

Already on the market are 1.4-nm derivatized or silver-coated gold particles that are produced by Nanoprobes, Yaphank, N.Y. Its nanoparticles can be used as chemically specific labeling reagents and immunoassay probes in light and electron microscopy, molecular biology, and cellular studies. And magnetic particles, such as those made of iron and activated carbon by San Diego-based FeRx, can be carriers for targeted drug delivery.

Metals and inorganics

Mach 1, based in King of Prussia, Pa., also plans to produce magnetic iron oxide for biological applications. The company has been making 3-nm iron oxide since 1992 and selling it for catalyst and solid rocket propellant applications. "Volumes are still small," company founder and President Bernard M. Kosowski says, measured in tens of thousands of dollars and bordering between pilot and semicommercial scale. However, he believes sales will increase as demand, supply, and pricing factors balance out.

"It's been more difficult to sell improved performance than I thought," Kosowski admits. "Incremental improvements will be outvoted by price every time." If micrometer-sized products are adequate at a significantly lower price than nanomaterials, they will continue to be used, he explains. "In this market, the cost-performance aspect becomes meaningful when your product offers a performance attribute that nothing else does."

Vapor-phase production is among the most commonly used processes, along with other combustion, sol-gel, and mechanochemical methods at different companies. Mach 1 recently licensed a microwave plasma process that it will scale up. A key feature, Kosowski says, is that it allows for making and coating inorganic nanoparticles for polymer, ceramic, and metal nanocomposites.

Nanophase Technologies, Burr Ridge, Ill., uses vapor synthesis and has particle encapsulation technology as well. One of a very few public nanomaterials firms, it reported $1.7 million in revenues and a loss of $2.7 million for the first six months of 2000. Its largest volume product--at hundreds of tons per year--is zinc oxide, which it supplies to BASF, Schering-Plough, and others for use as a sunscreen and fungicide in cosmetics and personal care products. Nanophase anticipates becoming profitable by late 2001.

Nanophase also sells other inorganic nanomaterials for catalyst and coatings applications. "In coatings, we're working in several different arenas from ophthalmic plastic lenses to vinyl flooring and applications where abrasion resistance is a particular interest," President and CEO Joseph Cross says. Another important project has been the development of thermal spray coatings, specifically metal oxide nanomaterials being used by the Navy to repair worn or eroded metal parts.

Altair Technologies, Reno, Nev., in collaboration with Nanopowder Enterprises, Piscataway, N.J., also is working on advanced ceramic coatings for the Office of Naval Research. Altair's primary product is nanocrystalline titanium dioxide. Its plans are to produce up to 1,500 tons per year as markets develop.

The major markets for nanoscale titanium dioxide--as a pigment, UV protectant, or material in surface coatings--total about 4,000 tons a year at about $20,000 to $25,000 per ton, says Michael Shonstrom, an analyst with the Denver-based firm Shonstrom Research Associates. In addition to small nanotechnology companies, suppliers include the traditional TiO₂ producers.

"Over the next couple of years, the nanomaterials area will grow significantly," Shonstrom adds. "Once the markets for nanomaterials start to become significant in size, which justifies the investment in larger scale production, major companies will move very quickly into this space and drive the costs down. It's just a matter of time."

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Sources: National Science Foundation Nanobase database, company information

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