Researchers develop fabric that automatically warms or cools its wearer

By Peter Holley / The Washington Post

Researchers from the University of Maryland say they have created a fabric that responds to its wearer, regulating the amount of heat that passes through the material.

If the wearer is sweating on a hot summer day, for example, the fabric allows heat to escape. But when the temperature is cooler and the air drier, the fabric becomes more compact, retaining heat from the wearer’s body, researchers say. The researchers’ paper, “Dynamic gating of infrared radiation in a textile,” was published in the journal Science.

YuHuang Wang — a U-Md. professor of chemistry and biochemistry who co-wrote the study — said he envisions a time in the not-so-distant future when clothing becomes a “secondary skin” that helps people save energy and reduce the costs of air conditioning and heating by relying on them less intensely or shut them off entirely.

“This technology would allow you to regulate your local environment, and that would give people a much wider tolerability for the heating and cooling conditions inside a building,” Wang said.

“How much could you get people to change their habits,” he said, referring to using clothing to offset energy costs, “that’s certainly an additional challenge.”

Three-quarters of homes in the United States have air conditioners, which use about 6 percent of all electricity produced in the United States, according to the Department of Energy. In addition to costing homeowners $29 billion annually, air conditioners release about 117 million metric tons of carbon dioxide into the air each year, the agency reports.

The research also offers a potential solution to another long-standing challenge, one that has inspired countless Inspector Gadget-like patents over the years: creating clothing that actively cools the wearer.

In 2015, Finnish researchers, inspired by the design of the human cardiovascular system, developed “a way of adding a plastic film containing microscopic channels filled with liquid to jackets and other clothes,” according to the Daily Mail.

By filling the clothing with liquid, the clothing could be cooled or provide insulation, the paper reported.

In Japan, researchers looking for novel solutions to energy shortages unveiled air-conditioned garments equipped with small battery-powered fans that could reportedly provide cooling air for up to 11 hours at a time, according to The Telegraph.

The fabric created by the U-Md. researchers doesn’t rely on batteries or liquid.

It starts with a specially engineered yarn coated with a conductive metal. When conditions are warm and humid — such as when the wearer is working out and sweating — the strands of yarn activate the coating, which in turn warps the strands of yarn, bringing them closer together. Once that happens, researchers say, pores in the fabric open, allowing trapped heat to escape. When conditions are cold, however, the process is reversed and heat remains close to the body.

To explain where the concept for the fabric originated, Wang compares the human body to an engine — one that coverts food energy to heat.

“If we are completely naked, our body is a perfect radiator that gives off heat so rapidly,” he said. “Most of our clothing is actually a good radiator, but we don’t control that radiator. We wanted to create a mechanism to control the heat being released by the body.”

Though the fabric has been developing for about five years, Wang said researchers are just beginning the process of turning it into a commercial product, most probably as a type of athletic wear initially. He said the fabric can be dyed, knitted and washed, offering the same durability as other commercial fabrics. Wang said he believes this clothing could have applications for people beyond cyclists and skiers.

“The performance may be effective for babies who need constant temperatures or perhaps the elderly or people who are sick,” he said.