The microstructure of negative electrocaloric Polyvinylidene fluoride-hexafluoropropylene copolymer on graphene loading for eco-friendly cooling technology

摘要

Extraordinarily negative electrocaloric materials are desirable for environment-friendly cooling applications. Stretched and unstretched Polyvinylidene fluoride-hexafluoropropylene thin films with suitable graphene contents have been studied in this work. The thin films were fabricated by solution casting method. Crystallinity was induced by stretching technique resulting a translucent film, with increasing dielectric constant, dielectric loss, conductivity and ferroelectric properties. By increasing the filler content, the maximum negative temperature change was intensified, and Curie temperature was decreased by 20 degrees C. However, a good electrocaloric effect was achieved without stretching, although stretching could stabilize Curie temperature to a smooth curve. The best performance in this work was found with graphene of 1 wt% (weight fraction of 0.01), which had an enhanced electrocaloric effect with a potential for electrocaloric cooling applications. (C) 2019 Elsevier Ltd. All rights reserved.