Extremely stretchable and healable ionic conductive hydrogels fabricated by surface competitive coordination for human-motion detection

Abstract

• A series of ionic hydrogels with regulated wrinkling surfaces were fabricated. • These ionic hydrogels exhibited robust mechanical strength and stretchability. • These ionic hydrogels exhibited a heat-accelerated self-healing performance. • Hydrogel capacitive skin sensor exhibited great sensitivity, wide range and durability. The construction of a surface-wrinkled ionic conductive hydrogel with highly stretchable and healable properties for a skin-inspired pressure sensor is desirable yet challenging. Here, a stretching/competitively-coordinating/releasing (SCR) strategy is presented for preparing a self-buckled polyacrylamide/alginate hydrogel (SPAH). Due to its high stretchability, excellent ionic conductivity and programmable wrinkled surfaces, the SPAH can readily work as an ionic conductor in a healable skin-inspired pressure sensor with adaptability and multifunctionality, achieving a wide pressure response range (25–20000 Pa), high sensitivity towards strain (3.19 kPa −1 ), low detection limit (<25 Pa) and excellent durability (>1400 cycles). As a proof-of-concept, a wearable SPAH pressure sensor can adequately monitor finger bending, knee flexion, speaking and breathing, showing high potentials in full-range and sophisticated motion monitoring across the applications involving human-machine interfaces, soft robotics, and artificial intelligence.