Heating pads are popular therapies to reduce stiff and aching joints. However, many heating pads and wraps are rigid and provide uneven warmth, especially when the person is moving around. Researchers in South Korea have now developed a bulletproof heating pad which could be used to make heated body armor for police and military personnel in cold climates.
Even at rest, the human body produces a lot of heat, but most of this warmth dissipates to the air and is wasted. Cold-weather clothing is often made from materials that keep heat close to the body, offering thermal insulation. For even more warmth, scientists have tried coating textiles with metallic nanowires that can be heated with a small battery. However, researchers are still searching for a material that provides good thermal conductivity and insulation while being safe, inexpensive, durable and flexible.
The researchers from the Ulsan National Institute of Science and Technology in South Korea reported their study in the journal Nano Letters.
In this study, a research group led by Associate Professor Park Hyung Wook of Ulsan National Institute of Science and Technology, South Korea, sought to make a wearable heating device by incorporating metallic nanowires into Kevlar®, the bulletproof fiber used in many types of body armor.
The researchers grew copper-nickel nanowires between two Kevlar sheets to make their wearable heater. They filled in the spaces between the nanowires with a resin containing reduced graphene oxide to encourage uniform heating.
The new fabric was strong, flexible, breathable and washable, while still absorbing impacts similar to regular Kevlar®. In addition to wearable heat therapy, the new material could be used to make heated body armor for police and military personnel in cold climates, the researchers say. Soldiers in the winter may find the new heating pad very helpful during their mission.