Thin, durable heating patches were created using intense pulses of light to fuse tiny silver wires with polyester. Their heating performance is nearly 70 percent higher than similar patches. The inexpensive patches can be powered by coin batteries and can generate heat where the human body needs it since they can be sewed on as patches.

This image shows how to make a personal heating patch from polyester fabric fused with tiny silver wires using pulses of intense light from a xenon lamp. (Hyun-Jun Hwang and Rajiv Malhotra/Rutgers University-New Brunswick)

It is estimated that 47 percent of global energy is used for indoor heating and 42 percent of that energy is wasted to heat empty space and objects instead of people. Solving the global energy crisis — a major contributor to global warming — would require a sharp reduction in energy for indoor heating.

Personal thermal management, which focuses on heating the human body as needed, is an emerging potential solution. Such patches may also someday help warm anyone who works or plays outdoors.

Intense pulsed-light sintering was used to fuse silver nanowires — thousands of times thinner than a human hair — to polyester fibers using pulses of high-energy light. The process takes 300-millionths of a second. When compared with the current state-of-the-art in thermal patches, the new design generates more heat per patch area and is more durable after bending, washing, and exposure to humidity and high temperature.

Next steps include determining if the method can be used to create other smart fabrics, including patch-based sensors and circuits. The engineers also want to determine how many patches would be needed and where they should be placed on people to keep them comfortable while reducing indoor energy consumption.

For more information, contact Todd Bates at This email address is being protected from spambots. You need JavaScript enabled to view it.; 848-932-0550.

Tech Briefs Magazine

This article first appeared in the April, 2019 issue of Tech Briefs Magazine.

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