Electronic-ionic polymer composite for high output voltage generation

Abstract

The ionic polymer transducers (IPT) have been widely proposed for actuators, energy harvesting, pressure sensing, and robotics applications owing to their exceptional flexibility and actuation performance. However, IPT sensors have a limitation of low output voltage (<1 V) with bending strain that hampers their application in energy harvesting devices and robotics. To address the issue of low output voltage in IPT sensors, we propose a strategy including the introduction of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) into a poly(vinylidene-fluoride-trifluoroethylene-chlorotrifluoroethylene) (P(VDF-TRFE-CTFE)/polyvinylpyrrolidone blend to develop the electronic-ionic polymer composite (EIPC) that exhibits a high output voltage of up to 27 V in ionic liquid (IL) condition. The PVP aids in the formation of 89 nm (nm) PEDOT:PSS crystals, a low contact angle of 53.75°, and pores on the surface of the P(VDF-TRFE-CTFE)/PVP/PEDOT:PSS-based EIPC with a ratio of 10/05/85, resulting in high water uptake (WUP) (0.92), high DC conductivity (σdc) (0.02 S/cm) and high electrical current 0.02 A/cm2, which improve the high output voltage (27 V) and output power density (4.05 W/cm2) compared to previous existing PEDOT based composites sensors and IPTs based on P(VDF-TRFE-CTFE)/PVP/ionic liquid, P(VDF-TRFE-CTFE)/PVP/PSSA and Nafion membranes. For wearable sensor application, the EIPC was attached to the index finger of humans and generated 25 V with bending of the finger with an angle of 180°. With high ductile nature (tensile strain 223%) and high output voltage of 27 V with bending strain, the EIPC sensors will find practical applications in strain sensors, wearable devices, and energy harvesting devices.