A research team at the University of Massachusetts Amherst has developed a fabric which harvests body heat to produce levels of electricity high enough to power small wearable devices. Published in Advanced Materials Technologies, the fabric concept takes advantage of the ‘thermoelectric’ effect, whereby a material at differing temperatures produces electric voltages which, in this case, can be harnessed. Materials chemist Trisha Andrew and her Ph.D. student Linden Allison vapour-printed biocompatible, flexible and lightweight polymer films onto cotton fabrics to yield thermal voltages which can power an accompanying smart device.