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 (ΔG′/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 (ΔG′) became negative definite, where the storage modulus under electric field (G′) was lower than the G′0 value. The negative ΔG′ 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. [Display omitted] •All MG/PLA/DBP composites behave as reversible electroactive materials.•0.1%v/v MG/PLA/DBP composite exhibits the highest storage modulus sensitivity.•The addition of graphene can provide positive and negative storage modulus responses.•Negative electrostriction under the presence of graphene.