Nanostructured coatings and layers, only billionths of a meter thick, can be applied to an object to protect against water, dirt, wear, and even bacteria. Working at the nanoscale, scientists and engineers are developing new and innovative applications in the fields of energy, electronics, and medicine. "Nanotechnology: Super Small Science" is produced by NBC Learn in partnership with the National Science Foundation.
Nanotechnology -- Nanotechnology at the Surface
KATE SNOW, reporting:
They protect against wear, against rust, against water damage. What are they? Nano-coatings and nanostructured layers only billionths of a meter thick - thinner than a fiber of silk. They can be applied to objects to repel water, improve visibility on a computer screen, or hide aircraft in the night sky. From semi-conductors to sunglasses to solar energy, nanostructured surfaces are all around us. And scientists and engineers are working on new applications every day.
L. JAY GUO (University of Michigan): When people use these terms such as nanostructured or nano-enabled structures, they typically mean that this composite or this type of material has some components or constituents that are in the nanoscale.
SNOW: Jay Guo is a professor of electrical engineering at the University of Michigan, researching nanoscale structures with funding from the National Science Foundation. He’s developing microscopic coatings, thousands of times thinner than tissue paper, that can control how light interacts with an object's surface - with potential applications in LCD displays, solar panels, and radar deflection.
GUO: I really like the science behind these nanostructures, and especially how I can make use of them for engineering applications.
SNOW: One way Guo's group structures nano-surfaces is by adding materials to the surface of an object. Here, they place a glass plate into a vacuum chamber and add carbon-mixed gas.
UNIDENTIFIED MALE (off screen): Heat it up and then open up.
SNOW: The chamber is heated to a certain temperature, and carbon nanotubes -- long, thin tube-shaped molecules -- begin to grow on the surface. A surface coated with nano-layers of carbon nanotubes can be engineered to absorb light waves - to reduce glare on a computer screen or possibly even make an object seem invisible.
GUO: The coating here is a multilayer coating. I think this one has five layers. But we design the structure such that it absorbs the entire visible light.
SNOW: Guo and his team also fabricate surfaces by removing materials through a process called etching, which creates nanoscale grooves on a surface. Inspired by the Morpho butterfly, which appears blue because of nanoscale structures in the wings that reflect blue light wavelengths, Guo's team etched surfaces that absorb or reflect certain wavelengths of light. This “structural color” research is being developed to improve LCD screens and to create more efficient solar cells. Guo also designs nanoscale films -- several thin layers stacked -- that reflect selected light wavelengths, such as red, white and blue, while using the absorbed light to generate electricity.
GUO: Basically, you design your panel to absorb certain portion of the light, so you can produce different colors or you produce white colors and so on and so forth.
SNOW: Other nature-inspired research comes from water-repellent and self-cleaning plants like lotus leaves, which are naturally covered in nanoscale bumps. Scientists and engineers have manufactured super-hydrophobic, or water-resistant, nanostructured surfaces and nano-layered coatings that cause water drops to bead up and roll off, removing dirt and debris as the droplets pass over the surface.
Similar surfaces and coatings will soon be used every day. Water and dirt resistant fabrics, anti-icing surfaces on airplanes, house paint, roof tiles -- all examples of products that have been structured to repel moisture. Specialized coatings also protect steel bridges and ship hulls, and medical instruments with specially engineered surfaces resist bacteria.
GUO: I think we're going to see more and more nanoscale structures that is used in our daily life. I think certain technologies that people are exploring right now, even in the laboratory scale, I think some of them will be able to transition to the real world, that benefit people in the society.
SNOW: With real-world applications that range from food preservation to self-cleaning glass, it's clear that nanotechnology will have a big impact, and that Guo and other scientists have only scratched the surface of its incredible possibilities.
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