Efficient self-repairing high permittivity cyanosilicone dielectric elastomers

Dielectric elastomers (DEs) always suffer from easy damage, cracks, tearing and breakdowns after detrimental events in practical applications. Endowing the DEs materials with self-repairing ability is an effective method to enhance the product reliability and extend the service lifetime. However, the preparation of DEs with ultra-high dielectric permittivity and efficient self-repairing ability is still challenges. Herein, we prepared silicone rubber-based DEs by regulating the carboxyl/ amino group ratio and cyano group content in polydimethylsiloxanes and tuning the polymer network structure by introducing the reversible ionically and hydrogen bonds cross-linking. The obtained elastomer materials possess an ultra-high dielectric permittivity (14.38 at 0.1 Hz), low Young's modulus (100-350 kPa), and their mechanical properties can be recovered to over 90% compared to the materials before cutting, exhibit high self-repairing efficiency. Furthermore, the influence mechanism of the network structure on the dielectric properties and efficient self-repairing performance of the silicone elastomers were detailed disclosed. The introduction of polar cyano group enhance the dielectric permittivity and facilitate the self-repairing performance by synergistic effect of the ionic and hydrogen bonds. This work paves the way for preparation of efficient self-repairing dielectric elastomer materials with prominent comprehensive performance.