Researchers Develop Heating Pads from Kevlar with Conductive Nanowires

Kevlar heating pads
Image Credit: American Chemical Society

The most popular remedy for minor aches and pains are electric heating pads. While these pads are cheap and easy to use, their rigidity and uneven distribution of heat, especially when the user is walking, make them very uncomfortable.

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Now, researchers at the Ulsan National Institute of Science and Technology in South Korea have developed a wearable heater by modifying woven Kevlar fabric with nanowires that conduct and retain heat. They report their results in ACS’ journal Nano Letters.

Our body produces a lot of heat, even when we’re resting. However, most of this heat evaporates in the air and is wasted. Cold-weather clothing offers thermal insulation because they’re made from materials that keep heat close to the body.

Kevlar heating pads

However, scientists are still searching for a material that provides good thermal conductivity and insulation, and at the same time, is also safe, inexpensive, durable and flexible. The Ulsan researchers wondered if they could make a wearable heating device by incorporating metallic nanowires into Kevlar, the famous bullet-proof fiber used in many types of body armor, reports Phys.org.

They modified Kevlar with copper-nickel nanowires placed within its layers. They used resin with reduced graphene oxide to fill in the space between the nanowires so when they get hot, the heat is distributed evenly. Using only 1.5 volts of electricity, the material quickly heats up to 158 degrees Fahrenheit evenly along its surface.

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The fabric they developed, turned out to be strong, flexible, breathable and washable, while still absorbing impacts similar to regular Kevlar. The researchers believe, besides using it as heat therapy, the new material could be used to manufacture heated body armor for police and military personnel in cold climates.