Here’s how they did it: They started with porous membranes made of polyurethane, a substance that has strength and elasticity – useful properties in fabrics such as spandex. Then they grafted on a layer of halamide molecules, forming a permanent chemical bond between the two dissimilar materials. The attached halamide layer has an affinity for liquid. When a liquid hits the hybrid material, this layer swells, absorbing toxins that might be in the liquid. “This will give the ultimate protection,” said Sun. “We can absorb, trap, and kill the bacteria.”
Sun and Obendorf also optimized the pore size of the membrane to allow perspiration to pass through, while blocking bacteria, which are much larger. Perspiration forms vapor droplets less than a nanometer in diameter – the equivalent of a few pairs of atoms lined up in a row. An anthrax bacterium, for example, is about one micrometer in size.
“Gang Sun’s pioneering work represents one of the major successes of National Textile Center-sponsored research,” said Martin Jacobs, executive director of the National Textile Center, a federally funded research consortium of eight U.S. universities. The NTC granted Sun and Obendorf $300,000 to create these materials. “He has generated both commercial and U.S. Air Force interest.”
Ultimately, Sun said, these garments could safeguard soldiers, medical workers, and civilians from harm. He and Obendorf are also working with the National Textile Center to develop fabrics for agricultural workers exposed to pesticides in an environment with high temperatures and high humidity, and hope to bring their textiles to market for all applications in two years. “If there is a potential risk,” said Sun, “these technologies can provide the best protection.”