Precisely manipulating polymer chain interactions for multifunctional hydrogels

Abstract

Stretchable and conductive hydrogels are essential in wearable electronics but often suffer from poor mechanical strength, large strain hysteresis, or deteriorated stability due to suboptimal polymer chain interactions. Here, we propose a precise inter-/intra-polymer-chain-interaction manipulation approach that endows hydrogels with excellent performance and multifunctionality. Our hydrogels exhibit high softness (∼200 kPa modulus), stretchability (∼180%), and conductivity (∼20 S/m) and excellent rebound resilience (energy loss coefficient <0.15). They also demonstrate excellent water retention and stability at room temperature. As a self-powered tactile sensor, these hydrogels can detect large strains at high frequencies (up to 50 Hz) and tiny stimuli (∼0.2% strain or 5 Pa pressure) with fast response time (42 ms). The key success lies in unique hydrogen bond networks and polymer chain entanglements achieved through plasticizer softening, freezing-thawing, and salt-soaking processes. This approach provides a fundamental solution and valuable insights for preparing intrinsically stretchable and conductive hydrogels for versatile applications.