Plasticized relaxor ferroelectric terpolymer: Toward giant electrostriction, high mechanical energy and low electric field actuators

Enhancing the electrostrictive strain under low electric field of a dielectric electroactive polymer (EAP) is essential in soft actuators applications. Conventional electrostrictive polymers suffer of the high electric fields usually required to reach sufficient strain. Here we report a new approach that greatly enhanced the strain under electric field and the mechanical energy density of fluorinated terpolymer EAP. A new all organic composite based on poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) terpolymer (P(VDF-TrFE-CFE)) doped with bis(2-ethylhexyl) phthalate (DEHP) was synthesized. DEHP molecule acts as a plasticizer that leads to large dipolar interfacial effects. This chemical modification allows a 28-fold increase of the electrostrictive strain and a 215-fold increase of the mechanical energy density. As a consequence, this new approach permits the uses of the exceptional properties of the fluorinated terpolymer for an electric field nearly 5 times lower and represents a simple and effective solution to this technological barrier. (C) 2013 Elsevier B.V. All rights reserved.