A self-healing dielectric supramolecular elastomer modified by TiO2/urea particles

Abstract

We designed and prepared a new dielectric self-healing elastomer (TuSE) by introducing the core-shell structured TiO2/urea particles into self-healing supramolecular elastomer (SE) assembled by hydrogen bonds. The urea on the outer shell of TiO2 particles forms hydrogen bonds with the amide groups in the molecular chains, so the TuSE materials exhibit higher self-healing efficiency than SE. The TuSE with 1% TiO2/urea particles (TuSE-1%) recovers its mechanical properties within 24 h at room temperature without any external stimulus. Moreover, the TiO2/urea particles effectively improve the dielectric constant (ε′) and actuated properties of the supramolecular elastomer. The TuSE-1% exhibits a much higher dielectric constant (ε′ = 16.1 at 1 kHz) and much lower elastic modulus (Y = 0.14 MPa) than those of SE (ε′ = 10.8 and Y = 3.78), resulting in a large increase in electromechanical sensitivity from 2.9 MPa−1 for pure SE to 115 MPa−1 for TuSE-1%. The dielectric elastomer actuator made of TuSE-1% shows a lateral actuation strain of 7.53% at 8.5 V μm−1, 20 times higher than that of pure SE (0.37% at 9 V μm−1). Additionally, TuSE-1% fully recovers its dielectric properties within 24 h, and the actuator can operate again after first breakdown.