Influence of graphene on electromechanical responses of plasticized poly(lactic acid)

Electro-responsive materials were fabricated from poly(lactic) acid (PLA), incorporated with dibutyl phthalate (DBP) as a plasticizer and graphene nanoplatelet as an effective nanofiller, via solvent casting method. The electromechanical properties and deflection of MG/PLA/DBP composites were investigated under the effects of graphene concentration and electric field strength. All composites possessed good recoverability during the temporal response experiment under applied electric field. At the 0.1% v/v graphene, the composite exhibited the highest storage modulus sensitivity (Delta G'/G'(0)) value of 1.88 at the electric filed strength of 1.5 kV/mm. At the graphene concentration of 1.0% v/v, the storage modulus response (Delta G') became negative definite, where the storage modulus under electric field (G') was lower than the G'(0) value. The negative Delta G' under electric field at room temperature has not been previously reported for any electrosrictive materials. Moreover, the pristine PLA/DBP showed the highest deflection distance and dielectrophoresis force relative to the composites at the electric filed strength of 550 V/mm, but the deflection distance of the composites decreased with graphene concentration. (C) 2018 Elsevier Ltd. All rights reserved.