Actuation and self-sensing performance of soft polymer actuator skin using polyelectrolyte attached terpolymer

Abstract

In this study, a soft polymer actuator skin is developed for stable actuation and generation of self-sensing voltage using electrolytes (NaCl, LiCl, ionic liquid) at room temperature (RT) that can be utilized for soft robotics and wearable voltage generation devices in the humid condition of the human body, respectively. We have developed poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) P(VDF-TrFE-CTFE) (terpolymer)/polyvinyl pyrrolidone (PVP)/polystyrene sulfonic acid (PSSA) based ionic polymer-metal nanocomposites (IPMNC) actuator skin for steady actuation at DC and AC voltage without back-relaxation and self-sensing behavior with various electrolytes. The terpolymer (terpolymer/PVP/PSSA) ionic polymer (IP) showed a large number of pores that enhanced water absorption, low Young's modulus, and high tensile strain than that of the PVDF copolymer (P(VDF-TrFE)/PVP/PSSA) and PVDF (PVDF/PVP/PSSA) IPs. The high porosity of terpolymer IP is responsible for stable actuation and self-sensing behavior of terpolymer IPMNC as compared to those of the PVDF copolymer and PVDF IPMNC. The terpolymer IPMNC generates the high sensing voltage with the pouring of the various electrolytes and sustains signals up to 1000s, which implies the self-diffusion of ions near the electrode of the IPMNC at RT. Our proposed soft polymer actuator skin could be utilized for wearable energy harvesting.