Effect of phenyl side groups on the dielectric properties and dielectric behavior of polysiloxane

Over the past decades, polysiloxane-based dielectric elastomers (DEs) have attracted significant research attention; however, the low dielectric constant and poor breakdown strength of polysiloxane limit its application in DEs. In this study, the effect of phenyl side groups on the dielectric properties and unique dielectric relaxation behavior of polymethyl phenyl siloxane (PMPS) was investigated. The dielectric constant of PMPS was slightly improved from 3.45 to 3.60 by introducing appropriate amount of the phenyl side groups into polysiloxane. Moreover, the electrical breakdown strength of PMPS increased from 31.70 to 35.91 kV mm- 1. The contribution of the alpha- and beta-relaxations significantly increased the dielectric loss of PMPS. To better understand the effect of the phenyl side groups on these properties, the dielectric relaxation behavior of copolymers with different phenyl contents was studied in detail via broadband dielectric spectroscopy and thermally stimulated depolarization current measurements. This study paves a new path to design and prepare polysiloxane-based soft materials with high dielectric constant and improved electrical breakdown strength.

Automated summary

This study investigates the effect of phenyl side groups on the dielectric properties of polysiloxane, and shows that introducing appropriate amount of phenyl side groups can improve the dielectric constant and electrical breakdown strength. The study also highlights the contribution of alpha- and beta-relaxations to the dielectric loss of the material.