Graphene/gelatin hydrogel composites with high storage modulus sensitivity for using as electroactive actuator: Effects of surface area and electric field strength

Abstract

© 2015 Elsevier Ltd. All rights reserved. The electromechanical properties of graphene/gelatin hydrogel composites were investigated under the effects of graphene surface area, electric field strength and temperature towards bio-actuator applications. The highest surface area of an embedded graphene (MG; grade M) in the gelatin hydrogel composites induced the highest dynamic modulus (G′) under applied electric field. The 0.1 vol% graphene (MG)/gelatin hydrogel composite possessed the highest ΔG′/G′<inf>o</inf> value of 352% in comparison with other materials in previous studies. Even the lowest ΔG′/G′<inf>o</inf> values obtained from the fabricated graphene/hydrogel composites were still greater than other dielectric elastomer materials investigated. The storage moduli of the pure gelatin and graphene (MG)/gelatin hydrogel composites, between 30 °C and 90 °C, exhibited three distinct regimes. In the deflection experiment, the bending distance and the dielectrophoresis force were found to increase monotonically with applied electric field strength with a deflection toward the anode side, indicating the attractive force between the anode and the polarized carboxyl group as the gelatin structure possessed negative charges under applied electric field.