Thiol-SAMMS is a simple, inexpensive and easy-to-use technology that absorbs mercury in liquids and can be easily disposed of afterwards.
Nanotechnology Is Everywhere
February / March 2005
Volume 3 Number 1
Nanotechnology eventually will disappear from public view. That's the prediction of researchers at the Pacific Northwest National Laboratory. According to Paul Burrows, manager of PNNL's Nanoscience and Technology Initiative, the average consumer will not even notice nanotechnology. "You won't go to the hardware store to purchase nanoparticles, you'll go to buy a widget that is made better because it incorporates nanotechnology," he says. Similarly, few consumers go to the store today to fetch silicon chips and yet almost every electrical appliance or automobile incorporates the chips.
Instead of a nanoscience industry, all existing industries are going to be improved and enabled for new applications with nanotechnology.
Nanoscience, the ability to see, manipulate and characterize at the nanoscale, is new, but nanotechnology, the application of nanoscale materials, has been around for some time. Although they didn't understand the science behind it, the Romans did it by ball-milling gold into nanoparticles to pigment the glaze on their vases. More recently, when you apply sunscreen on your nose it's transparent rather than white because it is made using engineered oxide nanoparticles. Nanotechnology is everywhere. There is, however, great untapped potential for nanoscale materials to enhance such areas as the automotive industry, electronics and power generation, which will be enabled by advances in nanoscience.
"PNNL has the ability to not only conduct basic nanoscale materials research, but also link that research to applications," explains Suresh Baskaran. "This ability, coupled with the Environmental Molecular Sciences Laboratory's capabilities to examine surfaces and interfaces, provides the tools to address this growing field of science." Baskaran leads the lab's Hydrogen Science and Technology Initiative and is instrumental in developing new projects in advanced materials and manufacturing technology.
The Environmental Molecular Sciences Laboratory, or EMSL, is a national scientific user facility where scientists from government laboratories, universities and private industry can access unique instrumentation and collaborate with scientists to investigate a broad range of phenomena at the molecular level. EMSL is a Department of Energy facility located on the PNNL campus in Richland, Wash.
"PNNL also has the right mix of people—€”material scientists, chemists, biologists and people who specialize in certain types of instrumentation and analytical techniques," he says. "Bringing these people together in a national laboratory environment—€”where we all are driven by the DOE missions in science, energy, national security or environmental technology—€”fosters great innovation in nanoscience and technology."
PNNL is an intrinsically interdisciplinary organization, which is important because in nanoscience, everything is at the interfaces. Both literally, because nanoparticles are almost all surface, and figuratively, because when working with nanoscale materials, you are basically working at the molecular level and chemistry starts to overlap with electronics, physics, engineering and even biology. All these disciplines start to merge at the nanoscale.
Because the field of nanoscience is so broad, collaboration between scientific disciplines is the key to moving nanoscience forward. No one area of discipline or organization is going to have all the answers. As a result, PNNL is seeking out industry and universities to partner with to bring all the right capabilities to bear on the problem.
***
Researchers at the laboratory are currently are working on several applications for advanced nanoscale materials. They include:
Lighting
"Possibly the most promising new lighting technology to emerge since liquid crystal displays (LCD), organic light-emitting diodes (OLEDs) are brighter and sharper then the ubiquitous LCDs," Burrows says. Organic light-emitting molecules also can be designed to use less energy. This technology is revolutionizing electronic displays for digital cameras, cell phones, car stereos and some prototype computer screens. The OLED future is bright with promise of applications for illuminating thin, flexible large-screen televisions and computer monitors that can be rolled up for storage. An ambitious new project funded by DOE's solid state lighting program aims to eventually make new plastic light bulbs based on OLEDs. Produced efficiently and inexpensively enough to compete with fluorescent and incandescent light bulbs in the marketplace, OLED lighting could reduce the amount of electricity used for lighting in the U.S. by 50 percent by 2020.
Thin Films
To manufacture thin, flexible and lightweight OLEDs for an application such as a computer screen that rolls up, a flexible surface that is impermeable to air and moisture vapor is needed. A team of scientists have developed two key technologies to address this design challenge—€”the Flexible Glass—„ engineered substrate that provides a flexible surface on which to build a display and the Barix—„ thin film coating that protects a display from harmful air and moisture. The Barix coating is made of extremely thin layers of transparent ceramic barrier material deposited with alternating thin polymer layers. The nanoscale inorganic layers (less than 50 nanometers thick) sandwiched between the polymer layers produce composite structures flexible enough to be rolled yet still prevent air and moisture vapor from passing through. The entire Barix coating typically is less than two microns thick. A human hair, on average, is 100 microns thick.
For the Flexible Glass, just like for the OLED itself, vacuum deposition techniques are used to deposit thin-film layers of nanoscale organic and inorganic materials in multilayer stacks directly onto a substrate such as polyester film. Each stack typically is less than two microns thick.
Both technologies have been licensed to Vitex Systems Incorporated. Vitex is a spinoff company of Battelle, which operates the laboratory.
Health Care
In the medical field, researchers are using supercritical fluids and RESS technology, or rapid expansion of supercritical solutions, to apply Teflon to vascular stents, a tool used to open arteries in the heart.
Typically, the human body rejects the stainless steel stents by growing tissue around the stent, reclogging the artery. Collaborating with industry partners, PNNL has successfully used the RESS process to coat the stents with a nanoparticle matrix of Teflon and a drug that prevents tissue buildup.
Waste Clean-up
Thiol-SAMMS, or Self-Assembled Monolayer on Mesoporous Supports, is a simple, inexpensive and easy-to-use tool that uses nanoscale technology to absorb mercury ions from water. While the PNNL-developed thiol-SAMMS has been tailored to absorb mercury, silver, lead and cadmium, other SAMMS technology is being developed for removing toxic contaminants such as arsenic, chromium, and radionuclide. SAMMS technology, including thiol-SAMMS, can be used in water and non-aqueous solutions.
Energy
As the U.S. attempts to move away from dependence on foreign oil and toward less-polluting forms of energy, converting wasted heat into useful energy is increasingly important. Scientists are using nanoscale materials to create a thermoelectric device to harvest and recover waste heat from diesel and gasoline engine exhaust systems and from primary production of industrial materials, including glass, aluminum and chemicals.
Enzymes
Researchers also have discovered how to expand the productive life of an enzyme from hours to months by caging it. The caged enzymes become SENs, or single-enzyme nanoparticles. The cage, just a few nanometers thick, is synthesized on the surface of the enzyme molecule using organic and inorganic materials to protect the catalyst. Converting free enzymes into enzyme-containing nanoparticles can result in significantly more stable catalytic activity.
Among the proposed uses for SENs is to break down toxic wastes, in which a single treatment could last months. Stabilized enzymes also are a prerequisite for many types of biosensors. And they may be of interest for coating surfaces, with applications ranging from medicine (protecting implants from protein plaques) to shipping (keeping barnacles off ship hulls). PNNL is investigating several other applications in the environmental and life sciences.
This article was written by Ginny Sliman, Rosalind Schremph, Sheila Bennett and Lisa Enderlin of the PNNL Communications Directorate.
Copyright © 2012 | Innovation America