Soft\nGel Filler Embedded\nElastomer with Surfactant\nImproved Interface for Dielectric Elastomer Actuators

Abstract

Stretchable materials are the foundation\nof dielectric\n actuators\n(DEAs) for artificial muscle. However, the inadequate dielectric constant\nof stretchable materials has always greatly limited the performance\nof artificial muscle. Recently, soft fillers have been proposed to\nimprove the dielectric property and preserve the stretchability for\nsoftness, aiming to avoid the stiffening effect of traditional rigid\nfillers. As composites, an amount of interfacial region is generated,\nwhich remarkably affects composites’ performance from dielectrics\nto mechanics. Herein, we demonstrate that the size effect, interfacial\nbinding, and compatibility have a great impact on soft filler doped\ncomposites. Particularly, according to the liquid characteristics\nof soft fillers, we explore an interfacial modification method using\nsurfactants. Composite breakdown strength is thus enhanced 2.2-fold\nfrom that in the control group due to the reduction of mismatch between\nfillers and matrix. Moreover, surfactants alleviate the well-known\nstiffening effect in small fillers. The area strain of the composites\nreaches 10.3 ± 0.4% at a low electric field of 7 MV/m, and a\nsoft micropump is successfully assembled. These findings demonstrate\na unique and combined interfacial influence of soft filler doped elastomer,\nwhich promotes the advancements of the dielectric elastomer artificial\nmuscle.