Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate)-Based Hydrogel Strain Sensors: Materials, Fabrication, Performance, and Applications

Hydrogel strain sensors are widely used in wearable electronics, human-machine interfaces, flexible electronics, owing to their ability to convert mechanical deformation into electrical signals. This function requires sensor materials to possess both high compliance and electrical conductivity. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has emerged as an ideal candidate for hydrogel strain sensors due to its soft and flexible mechanical properties, tunable mechanical performance, mixed ionic-electronic conductivity, and excellent processability. Although extensive research has been conducted on PEDOT:PSS-based hydrogel strain sensors, there is currently no systematic review that elucidates the translation pathway from high-performance materials design and advanced fabrication processes to diverse application scenarios. This review systematically examines the current state of development of PEDOT:PSS-based hydrogel strain sensors, following a logical progression from material design and fabrication processes to performance optimization and applications. It is expected to accelerate the development of PEDOT:PSS-based hydrogel strain sensors and expand their application space into a wider variety of fields.