Make plastic cool again

There is currently great interest in using materials that display pressure-driven thermal changes (barocaloric effects) for the purposes of refrigeration and air-conditioning, in order to replace the existing hydrofluorocarbon fluids that are environmentally harmful and volatile. However, the performance of these materials has historically been uncompetitive. We report superlative barocaloric effects in plastic crystals of neopentylglycol (CH₃)₂C(CH₂OH)₂ due to pressure‑driven changes of molecular configuration. Our discovery brings the performance of a solid material to the same level as the commercially used hydrofluorocarbon fluids, thus opening the (fridge) door to environmentally friendly cooling.

Figure: Pressure-driven thermal changes in neopentylglycol (NPG) are compared with other barocaloric (BC) materials and the commercial hydrofluorocarbon R134a (ΔS denotes entropy change, p denotes pressure).