Solvent Exchange-Assisted Wet Annealing and Salting-Out Strategy for Tough, Strong, Ultra-Stretchable, and Antifreezing Hydrogel

Abstract

Hydrogels are widely used in biomedicine, human−computer interaction, wearable electronics, etc. However, the development of conductive hydrogels that simultaneously possess high strength, high toughness, excellent stretchability, and antifreezing to meet diverse application scenarios remains a significant challenge. Herein, a new solvent exchange-assisted wet annealing−salting out strategy is proposed to prepare high-toughness poly (vinyl alcohol)-gelatin hydrogels by modification of the internal hydrogen bond network, structural densification, and adjustment of the crystallinity. Through the synergistic effect of annealing and salting out via solvent replacement of Li2SO4, the PGEH-ALi-conductive hydrogels are fabricated with excellent mechanical properties (9.7 MPa of tensile strength, 5316.5% of elongation at break, and 293.99 MJ/m3 of toughness) and outstanding environmental stability. These outstanding mechanical properties are superior to those of other elastomers. This work provides a new and effective strategy to fabricate tough, strong, stretchable, and antifreezing hydrogels with potential applications in numerous fields.