Charge Transport in a Filler-Free Silicone Rubber: Exploring Non-Linear Mechanisms and the “Liquid-like” Anomaly

The literature diverges about the understanding of DC conduction in elastomeric materials, as silicone rubbers, attributing the conduction whether to a solid or to a liquid one. In this study, three different liquid silicone rubbers (LSR) free of fillers are fabricated from the same bi-component raw material, but with different curing times and component proportions. They were submitted to current-voltage measurements at 40°C, with 1h polarization and depolarization cycles, from 1 to 10 kV. The current-voltage characteristics of a low cured sample presented a sub-ohmic profile. The sample cured and post-cured for a longer time presented an ohmic conduction. The non-stoichiometric material presented also an ohmic conduction, but with a deviation to a sub-ohmic at higher voltages. Moreover, its reversal currents in the depolarization profile were characteristic of blocking activity. Analysis of conduction in rubbers is proposed to explain the liquid-like behavior for elastomers, and the solid-like appearance in certain cases.