Enhanced bending electromechanical properties of maleic anhydride-grafted SEBS gels by blending with acrylonitrile-styrene copolymer

The poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS) gel which a type of electroactive thermoplastic elastomer has significant intrinsic electromechanical coupling effect owing to its unique microphase separated structure. However, the relationship between the structure and electromechanical properties of SEBS gel remains incompletely understood. This study investigates the effects of polar groups and nanostructure parameters on the bending electromechanical property of SEBS gel for improving its bending electromechanical properties, using maleic anhydride-grafted SEBS/white oil (WO) gel (SEBS-M gel) and blends of SEBS-M gel with acrylonitrilestyrene copolymer (SAN). The SEBS-M gel/SAN films exhibited a hexagonally packed cylinder (HEX) morphology, and the radius of polystyrene domains (rPS) as well as the thickness of poly(ethylene-co-butylene) (PEB) domains (dPEB) in the SEBS-M gel/SAN slightly decreased with increasing SAN content up to 15 phr, followed by an increase. The bending displacement and actuation stress of SEBS-M gel/SAN increased with increasing SAN content up to 15 phr. The bending displacement of SEBS-M gel at 1.4 kV is approximately 74 % of that of SEBS gel, while the bending displacement of SEBS-M gel/SAN-15 at 1.4 kV is approximately 195 % and 266 % higher than that of SEBS gel and SEBS-M gel when the SAN content reaches 15 phr, respectively. The grafted maleic anhydride has a counteractive effect on the bending electromechanical properties of SEBS gel, while blending with a certain amount of SAN in SEBS-M gel has a synergistic effect on the bending electromechanical properties of SEBS gel. It is demonstrated that the enchantment of bending electromechanical properties of SEBS gel is achieved not only by adjusting the parameters of its microphase-separated structure but also by inducing segment deformation through electric field-induced dipole orientations.