In the past few years nanomaterials have become integral components of products as diverse as sunscreens, electrically conductive coatings, and strong, lightweight plastic composites. Now nanomaterials are vying for new markets in electronics, food packaging, industrial processing and other areas. Leading the charge in these applications are a multitude of companies that range from small startups to the chemical and plastics giants.

Nanotechnology is now a $385 million per year business in the U.S., a figure that is expected to reach $3.5 billion by 2008 and $20 billion by 2013, notes a report by Consulting Resources Corp. (CRC), a Lexington, Mass. market research firm. For the years 2008 and beyond, the "increasingly significant" markets for nanomaterials, which typically range in size from 1 to 100 nanometers, will be in biomaterials, catalysts, diagnostics and electronics, the CRC study predicts.

Much of the cutting edge work in nanomaterials is being done by small companies, many of which have proprietary processes for making the tiny particles in highly uniform sizes, shapes and purities. Some of these firms have formed marketing and development alliances with large global chemical and plastics suppliers such as Honeywell, DuPont, BASF, GE, Bayer, Rohm and Haas, DSM and Mitsubishi. Degussa, meanwhile, recently started up a small internal venture to pursue advanced nanomaterials.

Commercial and developmental nanomaterials fall into three broad categories: metal oxides, nanoclays, and carbon nanotubes. Furthest along commercially are the metal-oxide nanoparticles, including oxides of zinc, iron, cerium and zirconium, as well as mixed-metal compounds such as indium-tin oxide. Current applications of the oxides include polishing agents for semiconductor wafers, sunscreen formulas and scratch-resistant coatings for glass.

The new nanomaterials venture at Degussa is in process of launching commercial lines of nanoscale zinc oxide, cerium oxide and indium tin oxide. The zinc oxide will serve as a UV filter in cosmetic applications, while the cerium oxide is being developed as a chemical mechanical planarization (CMP) agent to polish semiconductor wafers having very fine circuit features. The indium-tin oxide product is targeted at transparent, antistatic coatings for windows and electronic display screens.

Degussa developers also see applications of their nanomaterials further down the road. Dispersions containing the indium-tin oxide (ITO) nanoparticles, for example, might be used to coat an electrically conductive ITO layer onto touch screens and flat panel displays, instead of applying the layer by sputtering, the far more expensive process used now, notes Geoffrey Varga, director of Degussa Advanced Nanomaterials, Hanau-Wolfgang, Germany. "We're moving in the direction of making them sufficiently conductive" for the screen applications, Varga says of the ITO materials. Meanwhile, he says that Degussa is working with an undisclosed partner to employ ITO particles in transparent, antistatic coatings for plastic windows.

Degussa is also developing nanoscale iron oxide particles which could be loaded into adhesive formulations to allow "bonding and debonding on command," says Varga. The idea, he explains, would be to use an alternating magnetic field, applied by a mobile tool, to heat up the nanoparticles in an adhesive layer locally, so that the layer would soften and bond—or debond—the surfaces at the desired locations.

Elsewhere in the metal oxide nanomaterials field, Nanophase Technologies Corp., a small Romeo, Ill. firm, uses a proprietary plasma process to prepare nanoparticles with narrow size distributions, nonporous structures and nearly spherical shapes. Such materials would be less likely to fall apart in high-heat, high-stress environments like catalytic converters, as today's larger, less-uniform oxide catalyst particles often do, says Ed Ludwig, vice president for business development at Nanophase. In addition to its catalyst development work, Nanophase has an ongoing relationship with the Rodel division of Rohm and Haas to develop nanoscale metal oxides for CMP applications. A commercial supply agreement between Nanophase and BASF focuses on zinc oxides for sunscreens and personal care products. Ludwig describes BASF as "a major customer of ours."

BASF itself, which has long sold nanomaterials as pigments for coatings and plastics, has an ambitious nanomaterials development program. Among the firm's current projects are scratch-resistant films for plastics, water-repellent sprays that could be applied to shoes and other personal items, and materials that would store hydrogen for miniature fuel cells that could power mobile phones, laptops and video cameras.

Nanoclays are also advancing on many fronts. These materials are naturally occurring, plate-like clay particles which can be blended into plastics to form composites with improved strength, heat resistance, barrier properties and flame retardancy. The difficult part of the technology is to get the clay plates, which tend to stack up like playing cards, to exfoliate (disperse) in the polymer matrix. Many companies, including Toyota, which was a pioneer in the field, have developed their own methods of exfoliation. These approaches usually involve special coatings on the clays and adjustments of plastic extruders.

Nanocor Inc., one of the market leaders in nanoclays, sells the clay powders, to plastics compounders and processors. The Arlington Heights, Ill., company also offers pelleted concentrates of its nanoclays in polyethylene and polypropylene through its commercial alliance partner PolyOne Corp. Purchasers let down (dilute) the concentrates with plain plastic resin before the molding process begins. A third category of products consists of Nanocor's additives blended into nylon 6 and offered to the marketplace as ready-to-process pellets by two Nanocor licensees: Honeywell and Bayer. Typical applications of these products are in barrier films to keep oxygen out of plastic beverage bottles and paper juice cartons.

Nanocor is cooperating with PolyOne to develop other resin concentrates of its nanoclays, including products based on ethylene vinyl acetate, thermoplastic elastomers, ethylene propylene diene terpolymers, and nitriles. The pact is "a very active alliance with great potential," says Peter Maul, president of Nanocor. Nanocor also has teamed up with compounder Gitto Global Corp., Lunenburg, Mass., to develop flame-resistant polyolefin plastics, which have already been commercialized by Gitto. Another ongoing Nanocor alliance, with Japan's Mitsubishi Gas Chemical, has developed high-barrier nylon composites to keep out oxygen and carbon dioxide from multilayer films, bottles and thermoformed containers. "We're making commercial sales" of these products, says Maul, "and the market is quite interested in them."

Another nanoclay company, Southern Clay Products, Gonzales, Texas, has worked with General Motors and global polyolefins producer Basell for the past two years to create a nanocomposite thermoplastic olefin-based step assist for two GM auto models. These parts have already gone into production, reports Gerardo Lopez, commercial development manager at Southern Clay. He adds that his firm is still collaborating with Basell to optimize nanocomposite formulations and processing conditions. Although Southern Clay leans heavily toward automotive nanoclay applications, Lopez notes that "we are certainly pursuing" other outlets, including barrier packaging, wire and cable sheathing, and flame retardants.

Carbon nanotubes already find work as electrically conductive plastic fillers to dissipate static charges in equipment used to manufacture computer disk drives and semiconductor wafers. They also are used to make plastic automobile body panels conductive so that they can be electrostatically spray painted without the need for a costly primer coat. While the nanotubes compete in some of these applications with graphite fibers, the nanotubes work at much lower loadings than graphite and thereby minimize degradation of polymer properties.

Hyperion Catalysis International, Cambridge, Mass., is a leading player in the production and sale of multiwall carbon nanotubes for both of their current applications. One of its prime customers is General Electric, which employs the nanotubes, tradenamed Fibrils, in a grade of its Noryl polyphenylene oxide/nylon blends for electrostatically paintable car exteriors. Hyperion also sells nylon 12 masterbatches containing the nanotubes for static dissipation in automotive fuel lines, and polycarbonate/nanotube masterbatches for use in hard disk drive handling trays. Other concentrates, based on polyether ether ketone (PEEK) and polyether imide (PEI), are intended for use in electrically dissipative containers that transport semiconductor wafers during manufacturing.

According to Patrick Collins, marketing manager for Hyperion, the company is working on applications of its multiwall nanotubes as flame retardants in plastics. "There are preliminary scientific reports that carbon nanotubes are good flame retardants in polyethylene, polypropylene and EVA [ethylene vinyl acetate]," he says. The potential for such applications is particularly high in Europe, Collins notes, where there is pressure to eliminate current halogen-based flame retardants. Another research project at Hyperion is focusing on the nanotubes as conductive components in plastic antennas for high-speed wireless communications devices. The nanotubes would permit rapid bleed-off of charges that build up on such antennas, he explains, thereby making the antennas more efficient in devices that use high-speed digitally compressed signals.

Further back in the pipeline than multiwall carbon nanotubes are single-wall carbon nanotubes. These hollow cylinders of interlinked carbon atoms, known as fullerenes or Buckytubes, exhibit exceptionally high electrical and thermal conductivity, strength, stiffness and toughness, but have been hard to make in large quantities. But one startup, Carbon Nanotechnologies Inc., Houston, Texas, is now churning out commercial quantities of the nanotubes at a pilot plant using production technology it licenses from Rice University in Texas. The company has forged an alliance with DSM to develop the nanotubes for use in DSM's performance plastic fibers and films, which are made of ultrahigh molecular weight polyethylene. Another recent pact, with custom manufacturer Performance Plastic Products, aims for industrial plastics that can stand up to elevated temperatures, harsh chemicals, corrosive environments, extreme pressures and abrasion. Carbon Nanotechnologies also has licensed process technology to DuPont for use in making nanotubes with applications as field emitters in flat panel displays. Carbon Nanotechnologies also has an ongoing relationship with Sumitomo to market the nanotubes in Asia.

Despite advances in processing, single-wall carbon nanotubes are still more expensive than their multiwall counterparts. But Dan Colbert, vice president for major development strategies at Carbon Nanotechnologies, insists that the single-wall materials will give multiwall nanotube producers a run for their money. "If I were a multiwalled manufacturer," he says, "I'd be worried about being squeezed on the one hand by the high performance of our materials, and on the other side by the low cost of graphite fibers." How much of this erosion will actually occur, he adds, "is for the market to sort out."