Electromechanical Responses of a Crosslinked Polydimethylsiloxane

Abstract

AbstractA high molecular weight polydimethylsiloxane, PDMS, gel was prepared and investigated as an electroactive polymer actuator. Electromechanical properties of the PDMS gels were measured under an oscillatory shear mode at the temperature of 27 °C to determine the effects of crosslink ratio and electric field strength. The storage modulus, G′, of PDMS gel increases linearly with crosslink density but nonlinearly with electric field. The increase in the storage modulus with crosslink density is due to the increase in the number of junction points and strands. With increasing electric field strength, the storage modulus increases as the electric field induces dipole moments generating the electrostatic forces within the matrices. The gel with the crosslink ratio of 0.01 possesses the highest G′ sensitivity of 41% at 2 kV/mm. The temporal response of PDMS gels upon repeated applications of electric field strength of 2 kV/mm was investigated. For the crosslink PDMS (Nc/Nm = 0.01) system, at the electric field of 2 kV/mm, G′ immediately increases and rapidly reaches a steady‐state value. With electric field off, G′ decreases and nearly recovers its original value. The crosslinked PDMS (Nc/Nm = 0.01) is nearly a reversible system. Finally, we investigated the bending response of the PDMS films, suspended in silicone oil between copper electrodes. From the deformation data, we estimated the dielectrophoresis force, FD, to be a linear function of electric field strength.