Improving the electromechanical performance of dielectric elastomers using silicone rubber and dopamine coated barium titanate

In this work, a new soft dielectric elastomer (DE) was fabricated from dopamine coated barium titanate particles and silicone rubber (SR). The results showed that the barium titanate (BaTiO₃, BT) was coated by dopamine and the coated particles were highly compatible with SR. In order to achieve a maximum voltage-induced deformation, the minimum secant moduli of DEs were obtained in experimentation at a stretch ratio of approximately 1.6 by applying equi-biaxial tensile strain using the bubble inflation method. Additionally, it was found that the addition of DP-BT into SR led to an increased dielectric constant and decreased dielectric loss tangent for the matrix by comparison with SR/BT composites. Furthermore, the electromechanical properties of the SR/DP-BT composites were greatly improved in terms of voltage-induced deformation (s_a), electromechanical energy density (e) and coupling efficiency (K²). A maximum actuated area strain of approximately 78%, which was 30% larger than that of the SR/BT composites, was achieved for the sample having a DP-BT content of 20 wt.%. This strain corresponded to a low dielectric strength of around 53 V/μm, the composite exhibited a maximum energy density of 0.07 MJ/m³ and coupling efficiency of 0.68.