Influence of Plasticizers on the Electromechanical Behavior of a P(VDF-TrFE-CTFE) Terpolymer: Toward a High Performance of Electrostrictive Blends Nellie Della Schiava, 1,2 Minh-Quyen Le, 1 Jeremy Galineau, 1 Fabrice Domingues Dos Santos, 3 Pierre-Jean Cottinet, 1 Jean-Fabien Capsal 1 1 LGEF INSA de Lyon, 8 rue de la Physique, Villeurbanne, 69100, France 2 Groupement Hospitalier E. Herriot, Chirurgie vasculaire Pavillon M, 5 Place d’Arsonval, 69437 Lyon Cedex 03, France 3 Piezotech SA, Arkema Group, Rue Henri Moissan, Pierre Benite, 69310, France Correspondence to: P.-J. Cottinet (E-mail: pierre-jean.cottinet@insa-lyon.fr) Received 18 August 2016; accepted 10 November 2016; published online in Wiley Online Library DOI: 10.1002/polb.24280 ABSTRACT: This work aims at providing a complete analysis of the effect of plasticizers on the electrostrictive terpolymer per- formance. To achieve this, several plasticizing agents such as 2-ethylhexyl phtalate (DEHP), diisononyl phtalate (DINP), and palamoll 652 have been incorporated in the polymer matrix. Experimental results demonstrate that the proposed novel materials exhibited excellent electromechanical enhancement in terms of transverse strain and mechanical energy density under a moderate electric field, which is definitively critical in recent microscale actuation. Another objective of this article was to explore material characteristics as a function of the DINP content, and it was found that the plasticizer weigh fraction was the key parameter determining performance of the modified fluorinate terpolymer blends. Accordingly, it was revealed that high performance flexible actuators can be achieved merely by employing a simple and cheap plasticizer, thus making it possible to overcome the current technological barrier of conventional electroactive polymers that suffer from the high applied electric field usually required to reach suffi- cient strain. V C 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 355–369 KEYWORDS: actuators; blends; electroactive polymer; ferroelectricity; high performance polymers; printing electronic INTRODUCTION In recent years, polymers exhibiting good electromechanical behaviors have attracted a great deal of attention due to a wide range of possible applications in vari- ous areas like haptic feedback surgery instrumentation, 1–3 low-frequency energy harvesting, 4,5 actuation in micro- pumps, 6–8 artificial muscles, 9–11 flexible multifunctional sen- sor, 12 and so forth. 13 Among the polymers with large electromechanical responses, poly(vinylidenefluoride-trifluoroethylene) [P(VDF-TrFE)] copoly- mers are especially interesting because of their high piezoelectric response as well as their thermal and chemical stabilities. 14,15 New types of electrostrictive polymers known as poly(vinylide- nefluoride–trifluoroethylene–chlorotrifluoroethylene) terpoly- mers [P(VDF-TrFE-CFE)] has been investigated by Xia et al., and this study was based on the concept of defect structure modifica- tion of the P(VDF-TrFE) by addition of chlorofluoroethylene CFE in the form of a chemical monomer. 16 A similar idea was reported by Xu et al. where CFE was replaced by chlorotrifluoro- ethylene CTFE. 17 The authors demonstrated that the introduction of the “bulky” CTFE into the copolymer converted the normal fer- roelectric P(VDF–TrFE) into a ferroelectric relaxor with a high electrostrictive strain. Both modified polymers investigated in 16,17 exhibited excellent levels of conversion from electrical to mechanical energy. However, large electrical fields were required (>100 V/mm) to reach sufficient strain levels of above 2%. Actu- ally, the main drawback of most current electrostrictive polymer and dielectric actuators is their significant electric field requirement. Capsal et al. lately proposed a simple and efficient solution to improve the electromechanical behavior of the P(VDF-TrFE- CFE/CTFE) fluorinated terpolymer while applying a low elec- tric field. 18,19 It was revealed that by doping the polymer with the 2-ethylhexyl phtalate plasticizer (DEHP), it was possible to decrease the Young modulus as well as increase the dielectric permittivity, simultaneously. Such a simple chemical modifica- tion makes it possible to enhance the electrostrictive strain of the terpolymer at a low electric field that is approximately 5.5 times lower than that of the conventional material. Additional Supporting Information may be found in the online version of this article. V C 2017 Wiley Periodicals, Inc. WWW.MATERIALSVIEWS.COM JOURNAL OF POLYMER SCIENCE, PART B: POLYMER PHYSICS 2017, 55, 355–369 355 JOURNAL OF POLYMER SCIENCE WWW.POLYMERPHYSICS.ORG FULL PAPER