High‐Strength, Moisturizing and Conductive Hydrogels for Flexible Strain Sensors via Photoinitiated Polymerization and Ion‐Solvent Displacement

ABSTRACT In this study, we developed a novel double‐network multifunctional hydrogel with cross‐scale mechanical adaptability by employing a photoinitiated free radical polymerization synergy combined with glycerol‐salt ion‐solvent displacement approach. The novel hydrogel features a primary rigid network composed of polyvinyl alcohol (PVA) and gelatin (Ge), reinforced by an energy dissipation unit formed through a dynamic hydrogen bond network between acrylic acid (AA) and tannic acid (TA). Further enhancement was achieved via borax ion crosslinking and glycerol plasticization. The resulting PVA/PEG/AA/Ge/Glycerol (PEAAGG) hydrogel exhibited exceptional mechanical properties, including a tensile strength of 10.94 MPa, an elongation at break of 355.32%, and a toughness of 16.65 MJ/m 3 . Additionally, it demonstrated high electrical conductivity (0.15 S/m), good water retention (96.3%), and a controlled swelling rate (177.6%). The PEAAGG hydrogel sensor demonstrated a gauge factor (GF) of 0.94 under 0%–50% strain and 1.54 under 50%–125% strain, alongside rapid response times (235 ms vs. 222 ms) and high‐precision signal recognition. This innovative approach provides a novel solution for developing next‐generation intelligent soft materials.