Supramolecular polyelectrolyte film for spontaneous electricity generation with photoresponsive output signals and intrinsic recyclability

Abstract

Developing recyclable polymeric films for spontaneous power generation with stimuli-responsive output signals is a significant step towards sustainable wearable sensors, fashion textiles, etc., which remains highly challenging. Herein, we developed polyelectrolyte films for moisture-sorption-based electricity generation with photoresponsive electrical output signals from supramolecular co-assembly of alkaline solutions of lipoic acid (LA) and hyaluronic acid (HA) with amphiphilic azobenzene dopant and ionic liquid via an evaporation-induced polymerization process. Due to the intrinsic hygroscopic property and layer-by-layer structure with water channels, the corresponding polyelectrolyte films can absorb ambient moisture to induce charged ions dissociation and ion flow in the water channels, enabling spontaneous electricity generation. The polyelectrolyte film (0.4 cm × 1.5 cm) generated currents up to 11.8 nA at ambient conditions (21.6 °C and 69% RH). Notably, an immediate increase of current signal was observed by exposure to UV light because of variations in molecular geometry and polarity of the azobenzene dopant between trans and cis isomers. Besides, the polyelectrolyte films were easily recycled by dissolving in water and subsequent re-evaporation. The results demonstrated a new and simple pathway for developing recyclable supramolecular materials featuring spontaneous electricity generation with photoresponsive output signals, providing attractive opportunities for future sustainable advanced materials.