High performance silicate/silicone elastomer dielectric composites

In this study, we prepared a series of binary and ternary silicate/silicone elastomer dielectric composites with excellent actuation and energy storage performance by incorporating talc (Tl), wollastonite (Wl) and halloysite nanotube (HNT) into methyl vinyl silicone rubber (MVSR). Tl or Wl can act as physical barriers to prohibit HNT from aggregating to obtain uniform dispersion, which eliminates the step of surface modification and simplifies the preparation process. In this composite system, Tl and Wl effectively improve the breakdown strength of MVSR, while HNT significantly increases the dielectric constant of MVSR. It is worth noting that the addition of Tl reduces the elastic modulus of Tl/MVSR composites. The 40 wt%Tl/MVSR composite obtains the maximum actuated strain of 8.79% under low electric field of 35.96 kV/mm, which is 43.6% higher than pure MVSR (6.12% under an electric field of 47.1 kV/mm). The 10 wt%Wl/MVSR composite obtains the maximum actuated strain of 12.76% because of high breakdown strength. The ternary composite Tl-HNT/MVSR and Wl-HNT/MVSR play a synergistic effect in improving the dielectric and electromechanical properties due to the simultaneous increase in dielectric constant and breakdown strength. The 10 wt%Wl-10 wt%HNT/MVSR composite obtains the maximum actuated strain of 16.22% and energy storage density of 54.19 kJ/m3, which is 165% and 76.3% higher than pure MVSR (6.12% and 30.74 kJ/m3), respectively. This work establishes a simple and effective method for high performance dielectric elastomer composites.