Improved electro-actuation property of dielectric elastomer composites regulated by one-dimensional CaCu₃Ti₄O₁₂@TiO₂ core-shell construction

Dielectric elastomers (DEs) are typical electro-active polymers that can achieve an electro-actuated deformation under an applied electric field. However, obtaining a large low-field-actuated strain of DEs is still a key challenge, which is critical to their practical application range. Herein, a typical CaCu3Ti4O12@TiO2 (CCTO@TiO2) core-shell-structured nanowires were synthesized by the micro-emulsion method. Additionally, a series of polydimethylsiloxane (PDMS)-based DE composites combining variable proportions of CCTO@TiO2 were prepared. The CCTO@TiO2 nanowires with the design of both decreasing dielectric constant from core to shell and a high aspect ratio can provide larger heterogeneous interfaces for the DE composites, leading to a promoted interfacial polarization. The maximum electro-actuated strain of 37.66% is achieved from the DE composite incorporated with 20 wt% CCTO@TiO2 when subjected to a relatively low electric field of 40 V/mu m, which is 14 times higher than that of pure PDMS (strain similar to 2.5%). Moreover, the composite exhibits the largest electro-actuated strain (45.83%) under the electric field approaching its breakdown strength of 43.57 V/mu m. The results demonstrate that the one-dimensional core-shell nanowires have a positive effect on improving the low-field-actuated strain of DE composites. This research reveals an effective and feasible method to prepare the DE composites exhibiting enhanced low-field electro-actuated characteristics.