Multifunctional Solid Polymer Electrolyte Films Integrating Intrinsic Self‐Healing and Dual Photo‐/pH‐Responsive Ionic Sensing for Intelligent Flexible Electronics

ABSTRACT

Solid polymer electrolytes (SPEs) that are simultaneously stretchable, self‐healable, and stimulus‐responsive are highly desirable for next‐generation flexible and intelligent electronic systems, yet remain challenging to realize within a single material platform. Here, we report multifunctional SPE films that integrate intrinsic self‐healing, mechanical stretchability, and dual photo‐ and pH‐responsive ionic conductivity. The electrolyte films are constructed from elastomeric thermoplastic polyurethane (TPU) and a hydrogen‐bond‐rich poly(thiourea triethylene glycol) (PTUEG ₃ ), forming a dynamic supramolecular network capable of efficient mechanical healing. Incorporation of an azobenzene‐based ionic liquid, [AzoC ₆ MIM][Br], not only provides mobile charge carriers but also introduces reversible light‐ and acid‐responsive molecular transformations. Photoinduced trans–cis isomerization enables reversible modulation of ionic conductivity under alternating UV and visible light, while acid–base vapor exposure triggers protonation–deprotonation of the azobenzene moiety, leading to pronounced and tunable conductivity changes. Notably, the films retain high stretchability, robust thermal stability, and repeatable healing performance, even under cyclic mechanical deformation. This work demonstrates a generalizable strategy for coupling supramolecular self‐healing networks with molecularly programmable ionic species, offering a versatile materials platform for adaptive solid electrolytes, soft sensors, and intelligent energy‐storage interfaces.