Spatiotemporal Regulation of Ion Transport via Photothermal Heating in Azobenzene-Based Polymer Networks

Abstract

Azobenzene, a versatile molecule capable of reversible photoswitching between its trans and cis isomers upon exposure to specific wavelengths of light, presents unique opportunities to amplify molecular-level transformations into macroscopic property changes in polymers. Herein, we report an approach for modulating ionic conductivity in polymer networks using light by incorporating azobenzene photoswitches as pendant groups within poly(ethylene glycol) ionogels. While previous reports show that photoisomerization affects ion transport via changes in molecular interactions, we find that the photothermal effect dominates ionic conductivity modulation in polymer networks, enabling rapid and reversible conductivity enhancements under both UV and visible light. Our findings demonstrate a reversible enhancement of ionic conductivity by 40 to 110%, driven by localized heating from light-absorbing azobenzene moieties. These findings highlight promising implications for applications in flexible batteries, sensors, and actuators, where light-driven control of ion transport could offer advantages in device design and performance.