Is nanotechnology a myth borne of hype and marketing, or is it reality? The answer depends on your perspective. The general public may think that expectations are ridiculously high and the technology won't be viable. Not so, though, for many of the world's top scientists and engineers, who are still feverishly at work on furthering this technology. Still, it will take some time before products are realized.
The National Center for Manufacturing Sciences (NCMS) conducted a survey of 600 manufacturing companies last year to gauge the optimism for nanotechnology's future. Sponsored by the National Science Foundation (NSF), it's the largest cross-industry survey of nanotechnology commercialization trends to date. So what did the final numbers say?
Stunningly, results revealed that 60% of respondents expected to market nanotechnology products by 2009 (Fig. 1). Participating companies included automotive, semiconductor, chemical, aerospace, energy, utility, textile, food, agriculture, construction, machine-tool, mining, and information technology firms.
Aggressive funding for nanotechnology worldwide continues unabated. According to NSF statistics, the U.S., Japan, and the European Union each spent about $1 billion on nanotechnology last year. Worldwide funding totaled over $4 billion (Fig. 2).
Better Materials To EmergeWithin the next three to five years, experts predict a myriad of new applications to emerge from advanced nanocoatings, nanofilms, and nanoparticles now under development. In turn, these materials will be used to enhance electronic components and subsystems, as well as textiles. Such tailored materials will give engineers greater control over design parameters.
The Massachusetts Institute of Technology (MIT) is working on electrode structures for ultracapacitors based on a matrix of vertically aligned carbon nanotubes. The development is expected to increase present-day ultracapacitor energy densities of 6 Whr/kg to 60 to 100 Whr/kg.
Scientists at NASA's Jet Propulsion Laboratory are looking into infrared (IR) imaging arrays using nano materials that work at room temperatures. Unlike conventional IR sensors, which are based on bolometry or conventional semiconductor photodetection, these imagers don't require supercooling. High levels of detectivity and rapid response times can be attained at room temperatures. They use crossed nanowires with dielectric barriers between them. The barriers consist of quantum mechanical tunneling junctions (Fig. 3).
Nanogenerators are under the microscope at the Georgia Institute of Technology. They convert mechanical energy into electric currents. Researchers use very small piezoelectric discharges, which are created when zinc-oxide nanowires are bent and released. By interconnecting millions of the wires into an array, enough current can be produced to power nanoscale devices.
Despite these undertakings, the MIT survey revealed critical industry barriers to commercialization. These include the high cost of processing; lengthy times to market; insufficient investment capital; intellectual-property issues; a shortage of qualified manpower; and regulatory, safety, and environmental concerns.
Each of these issues is being addressed, with some progress. But the pace simply isn't fast enough for the market's large expectations. Like any other evolving technology, nanotechnology needs to successfully pass from the research phase to the development phase, and then on to the manufacturing phase. Each of these phases requires a thorough understanding before the technology can succeed.
Progress has been made in achieving a better understanding of the basic nanotechnology material—carbon nanotubes. Researchers apply combinations of a top-down manufacturing approach (like that used to create silicon ICs) with a bottom-up approach that's found in building structures from atoms and molecules.
A group headed by Ahmed A. Busnaina at Northeastern University's Nanomanufacturing Research Institute has completed important groundwork in nano manufacturing. The group has crafted nanomanufacturing templates, as well as a means for interconnecting nanostructures. It also has pioneered novel approaches to microcontamination control.
Even conventional semiconductor photolithography systems have shown the ability to manufacture nanostructures. A team of researchers from the University of Wisconsin at Madison, Germany's Georg-August University, and the Paul Scherer Institute in Switzerland discovered that materials known as "block polymers" will spontaneously assemble into intricate 3D shapes. This occurs when they're deposited onto particular 2D surface patterns created by photolithography.
Carbon nanotubes are the fundamental elements in building nanocircuits. Though they have their own manufacturing methodologies—arc discharging, laser ablation, and chemical vapor deposition—progress has been made in integrating their manufacture onto ICs and microelectronic packages. A team at the Georgia Institute of Technology is proposing a new paradigm for transferring and integrating carbon nanotubes, making integration easy with present semiconductor manufacturing equipment.
Advances in nanotechnology are also happening at the device design level. Researchers at Hewlett-Packard have invented a completely new way of designing nanocircuits using coding theory (Fig. 4). The development has implications for low-cost manufacturing.
As a benefiting material, nanotechnology may well appear on the market in manifestations that aren't obvious to the average consumer. Natural Nano recently licensed key patents to provide selective wireless access in RF shielded environments that will use a "Personal Communications Device Connectivity Arrangement" created by Ambit Corp. The scheme selectively turns access to radio signals, such as those used by cell phones or wireless computer networking devices, on or off in areas that are otherwise shielded from those signals.
This method of access control makes use of metallized halloysite carbon nanotubes. Using such nanotubes for RF shielding came about as a result of a Natural Nano R&D program. Experimental trials included the creation of a spray coating embedded with the copper-filled halloysite nanotubes. The resulting material demonstrated significant RF signal-strength reduction capability.
A spray-on shielding formulation, when applied to the walls of a room, provides a passive blocking agent for RF energy. This technology, says Natural Nano, is particularly applicable to existing and non-mobile rooms, due to the high costs associated with retrofitting an existing room to make it a passively RF shielded environment using current RF shielding techniques (see "So You Won't Turn Off Your Cell Phone? Don't Worry—The Paint Will," at www.electronicdesign.com, ED Online 12327).
Needed: A Nano Roadmap To speed up nanotechnology's commercialization, some groups are launching roadmap initiatives. One such group is the Nanoelectronics Standards Roadmap Initiative, formed by the Institute of Electrical and Electronic Engineers (IEEE) in May.The IEEE intends to move innovations from the lab to the marketplace for communications, consumer, biomedicine, information technology, and optoelectronics applications. Possible harmful consequences aside, there's no question among many researchers that nanotechnology will provide fantastic benefits in the future. It's only a question of when.
Consider targeted photothermal therapy. Biomolecules that target cancer cells can be attached to gold nanoshells, which absorb infrared light to fight cancer. Injected into the body, they stick to the cancer cells as they flow throughout the body and flush out everywhere else.
The gold nanoshells are calibrated to a diameter that makes them absorb a specific wavelength of infrared light. They absorb the light, which would otherwise just pass through the body, and convert it to heat. Thus, the tagged cancer cells are cooked to death. Clinical trials for using targeted photothermal therapy are already in the planning stage, pending approval from the Food and Drug Administration (FDA).
Kevin Ausman, executive director of the Center for Biological and Environmental Nanotechnology at Rice University, says that "this example gives you a flavor of the way that tuning these special properties of materials by controlling their size can do some exciting things. \[In this case\] it's for bioengineering, but it also shares that promise for mechanical engineering, for new forms of water treatment and new types of \[stain repellent\] clothing."
Targeted thermal phototherapy isn't nanotechnology's only medical benefit. Someday, molecular-scale robots will clean cholesterol and bacteria from the bloodstream as well.
Other possible applications? Looking at nano's potential, they're seemingly limitless.