Enhanced Actuation Performance of Polymeric Composites by Simultaneously Incorporating Covalent-Bond-Functionalized Dielectric Nanoparticles and Polar Plasticizer

Dielectric elastomer actuators (DEAs), similar to artificial muscles, are widely applied in the fields of robotics and biomedical devices. In this work, 3-mercaptopropyl ethyoxyl di(tridecyl-pentaethoxy) silane (Si747)-modified BaTiO₃ (BTO) nanoparticles (denoted as Si747@BTO) were utilized as dielectric filler to improve the dielectric constant while epoxy soybean oil (ESO) was employed as a plasticizer to decrease the elastic modulus, with the aim of improving the actuation performance of epoxy natural rubber (ENR) composites. The participation of Si747 in the vulcanization reaction of ENR led to the formation of covalent bonds between BTO and ENR chains, resulting in a uniform dispersion of BTO nanoparticles in the ENR matrix. Among obtained composites, the 50 phr ESO/Si747@BTO/ENR exhibited a relatively high actuated strain of 8.89% at 22 kV/mm, which is a value about 5.1-fold higher than that of pure ENR (1.45%) under the same electric field.