Excellent dielectric and actuated strain properties in CCTO_x@BT_(1−x)@KH560/NR system via a tunable BaTiO₃ interfacial buffer layer

Abstract

Dielectric elastomers (DEs) require high drive voltages to obtain large actuated strain, which limits their application in the biological field. In this work, we enhanced the dielectric properties of natural rubber (NR) composites by using core–shell structured (CaCu3Ti4O12)x@(BaTiO3)(1−x) (CCTOx@BT(1−x)) high‐dielectric particles with an buffer layer, and adjusted the thickness of the BT buffer layer by adjusting the addition of titanate during the preparation process, and then observed the relationship between the dielectric properties of NR composites and the thickness of the BT buffer layer. In addition, we modified the CCTO0.75@BT0.25 fillers surface with silane coupling agent KH560 to enhance the interfacial interaction between the inorganic fillers and polymeric matrix to obtain better dispersion and greater dielectric properties. As a result of the optimization of the CCTO0.75@BT0.25@KH560 structure, the actuated strain performance is greatly improved. The actuated strain of 5 per hundred rubber (phr) CCTO0.75@BT0.25@KH560/NR is 16.3% at 74.03 kV/mm, which is 6.52 times higher than the actuated strain obtained by NR (2.5%) at 50.28 kV/mm. This work presents a method to optimize the structure of core–shell fillers by modulating the buffer layer, and provides a new idea for further preparation of dielectric elastomer materials with large actuated strain at low voltage.