Stretchable High Response Piezoelectric Elastomers Based on Polable Polynorbornene Fillers in a Polydimethylsiloxane Matrix

Abstract

To advance the field of piezoelectrics, it is desirable to find materials that combine high piezoelectricity with high elasticity. Applications such as self-sensors, stretchable electronics, soft robots, and energy harvesting would benefit tremendously. However, this is not an easy task neither for materials based on ceramics nor for those based on polymers. While ceramics can show strong piezoelectric effects, their mechanical response tends to be weak. Polymers instead are elastic but only few have sizeable piezoelectric effects. Additionally, they cannot maintain the polarization permanently as needed for piezoelectrics. Here, an all-organic piezoelectric elastomer is synthesized by blending high glass transition temperature (Tg = 104 °C) polar polynorbornene nanoparticles (NPs) with a high relaxation strength (Δε′ = 22.4) into a chemically cross-linked polydimethylsiloxane matrix. After processing the blends into thin films by doctor blading, they are poled by corona discharge at elevated temperatures. Fifteen days after poling, the materials show a stable and reversible piezoelectric response d31 = 37 pC N−1. This, to the best of the authors’ knowledge, not only is the highest d31 value reported, but the response is three times that of the well-known polyvinylidene difluoride.