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

• BaTiO3 was modified with dopamine.
• The coated particles improved the dielectric properties of DEs.
• Mechanical properties were obtained via the bubble inflation testing system.
• A large voltage-induced strain of 78% was achieved by the fabricated DE.

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 (sa), 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.

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