Minimization of losses in natural rubber films for dielectric energy harvesters

Energy harvesting is a comparably new and increasingly developing branch of the sustainable energy sector. Being versatile in their design and attractively simple in the working principle, dielectric elastomer generators (DEGs) form a promising class of wave energy harvesters. The efficiency and energy output of a DEG depends on many factors, including the properties of dielectric elastomer material. The existing harvesters utilize elastomer membranes that are lacking all the necessary properties to make DEG economically viable. Therefore, elastomeric material designed especially for the DEG application is in demand. Natural rubber (NR) films have already been utilized in DEGs, and NR outperformed other elastomeric materials often used in such devices in terms of dielectric and viscoelastic losses. The present study is focusing on comparing dielectric loss properties of different NR types by using broadband dielectric spectroscopy, and shows the possibility to minimize losses by the addition of small amounts of nanodiamond filler into the rubber matrix. Moreover, viscoelastic loss properties of the rubber and rubber-nanodiamond composites are investigated by means of dynamic mechanical analysis and cyclic tensile loading.