A High Strength Hydrogel with a Core–Shell Structure Simultaneously Serving as Strain Sensor and Solar Water Evaporator

A super‐strong poly (acrylic acid)‐ poly(3,4‐ethylene dioxythiophene) (PAA‐PEDOT) hydrogel with a unique core‐shell structure is successfully constructed and studied. The shell composed of the conductive polymer PEDOT makes the composite hydrogel possess mechanical strength, electrical conductivity, and photothermal conversion properties, while the PAA hydrogel core ensures the flexibility, recovery, and water absorption of the composite hydrogel. The prepared PAA‐PEDOT hydrogel displays outstanding tensile strength (up to 780 KPa) and satisfactory conductivity (6.6 S m−1). Notably, the flexible strain sensor made of PAA‐PEDOT composite hydrogel presents both high sensitivity (gauge factor up to 8.87) and short response time (