A P(VDF-TrFE) copolymer with VDF content of 68 mol% was used in this study and it has a weight-average molecular weight (Mw) of 367,000 and a polydispersity of 2.7. P(VDF-TrFE-CFE) with VDF/TrFE/CFE molar ratio of 63/37/7.5 was synthesized via suspension polymerization using an oxygen-activated initiator (For easy comparison with the P(VDF/TrFE) copolymer, we use VDFx/TrFE1−x/CFEy to describe the
composition of the terpolymer, where x/(1−x) is the
VDF/TrFE mole ratio and y is the mol% of CFE in the terpolymer) [9]. The terpolymer has a Mw of 670,000 and Mn of 238,000. Molecular weights were determined by gel permeation chromatography using narrow molecular weight polystyrene as standards and tetrahydrofuran as the mobile phase. These two compositions were selected since they have similar VDF/TrFE ratio.