Phase change material

Clothing can now be engineered to respond to body temperature by coating fabrics with a paraffin wax like substance known as phase change material. These materials are encapsulated in microscopic balls of heat-resistant plastic. The phase change material melts and freezes before the person wearing the apparel does, and in the process, stores and expels heat energy. Phase change materials work because they are designed to maintain the midpoint of narrow temperature range. The specific range is determined by the lengths of the hydrocarbon molecules that make up the material. The two companies which specialize in the production of these materials are Frisby Technologies in Winston-Salem, NC, and Outlast Technologies in Boulder, CO.