Electroactive polymers are smart materials that respond to electrical stimulation by changing their shape and size. The objective of this study is to investigate the applicability of the poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer in sensors or actuators in an in vivo environment. The basic mechanical properties of P(VDF-TrFE) thin films were estimated by carrying out tensile and creep tests using specimens submerged in water at 30 degrees C for a few weeks. Furthermore, X-ray diffraction analysis was employed to observe the micro-structural changes in the P(VDF-TrFE) films due to water absorption wherein water intercalated in the interstitial sites between the chains of the P(VDF-TrFE) films. Consequently, the mechanical properties of the P(VDF-TrFE) films were enhanced due to water absorption. (C) 2013 Society of Plastics Engineers