Christina Tang, an assistant professor at Virginia Commonwealth University, tests tissue that changes color with temperature and in contact with bacteria and viruses. This effect is achieved by the rotation of liquid crystals in the fibers, the researchers noted.
Tang and her students believe that these “smart fabrics”, which are made of soft, lightweight and elastic materials, can be used in clothing, for example, for disguise, or for other purposes, such as detecting the presence of a pathogen such as a virus. They have also been used to create wearable sensors and devices.
Tang’s lab produces nonwoven nanofibers similar to the fibers in reusable shopping bags. Scientists claim that such fibers can be easily mass-produced.
“We like to think about how we can add functionality to familiar materials”, — said Christina Tang.
In the case of the N95 mask, she says, the wearer will know "when to change it, instead of just guessing." With cleaning wipes "you can keep wiping until they stop changing color."
In his research to understand the fundamental properties of these materials, Tang is testing how to create thermochromic fibers by incorporating liquid crystal compounds into nanofibers (created by electrospinning).
Tang said some researchers in the field are focusing on liquids, while others are focusing on polymers. Her approach, which is at the intersection of the two, applies methods commonly used for liquids to these materials.
Liquid crystals, which sit between the liquid and solid phases, have the optical property of reflected color - “the same principle that gives color to the wings of a butterfly instead of dyes that absorb color”, — Tang said.