A Skin-Inspired Multifunctional Conductive Hydrogel with High Stretchable, Adhesive, Healable, and Decomposable Properties for Highly Sensitive Dual-Sensing of Temperature and Strain.

Developing smart hydrogels with excellent physicochemical properties and multi-sensing capabilities for various simulation of human skin's functions still remains a great challenge. Here, based on simple and convenient one-step covalent cross-linking method enhanced by dynamic RS-Ag interactions, a skin-inspired multifunctional conductive hydrogel with desirable physicochemical properties (including high stretchability, self-adhesion, self-healing, decomposition and removability) is developed for highly sensitive dual-sensing of temperature and strain. Benefiting from the synergistic action of multiple hydrogen bonds, RS-Ag bonds and S-S bonds, the gel exhibited a novel thermosensitive mechanism. The prepared hydrogels exhibited extremely high mechanical properties (maximum tensile strength of 0.35 MPa, elongation at break nearly 1800%, compressive stress over 4.43 MPa), excellent self-healing (96.82% (stress), 88.45% (temperature), 73.89% (mechanical property)), decomposition (the molecular weight after decomposition is below 700) and self-adhesion (enhanced contact with the material interface). In addition, this conductive hydrogel could also simultaneously achieve highly sensitive temperature-sensing (TCR: 10.89) and stress-sensing (GF: 1.469). As a proof-to-concept, the hydrogel displayed superior capability for simulation of human skin to perception of touch, pressure and ambient temperature simultaneously, indicating promising applications in the fields of wearable devices, personal health care, and human-machine interfaces.