Electrostimulus Phase-Transition Mediated Robust Adhesive Hydrogels.

Abstract

Adhesive hydrogels are crucial for interfacing wearable electronics with substrates, yet the inherent trade-off between interfacial adhesion and cohesive strength always limits their application performance. Here, we present an adhesive hydrogel based on lignin-mediated catechol chemistry and salt hydrate phase-transition, which achieves synergistic enhancement of interfacial adhesion and cohesive strength upon 1 V electrostimulated crystallization. The hydrogel is soft and exhibits mild adhesion to various substrates in amorphous state. Electrostimulus-induced phase-transition realizes a significant increment of cohesive strength and boosts interfacial adhesion by up to 8-40 times (exceeding 3000 J m-2) on skin. The adhesion-enhancement mechanisms on different substrates are elucidated via multi-scale experimental designs and molecular simulations. When the hydrogel is applied as the adhesive layer, the assembled elastomer sensing devices inherit the electrostimulus adhesion-enhancement and shape-memory properties, significantly improving signal transmission stability and motion-interference resistance. This study offers a simple and versatile strategy for stimuli-enhanced adhesives, deepens the understanding of phase-transition regulated adhesion behaviors, and supports the development of large-area flexible devices for intelligent robotics and human-computer interactions.