Tough Thermosensitive Hydrogel with Excellent Adhesion to Low-Energy Surface Developed via Nanoparticle-Induced Dynamic Crosslinking

Abstract Stimuli-responsive adhesive hydrogels have obtained increasing attention due to their applications in drug delivery and wearable sensors. However, these hydrogels exhibit weak mechanical properties and poor adhesion, especially on low-energy surfaces. Here, a temperature-responsive adhesive hydrogel was developed based on mussel-inspired dopamine chemistry and core-shell nanoparticle-regulated dynamic cross-linking. Poly(N-isopropylacrylamide) (PNIPAM) was used as the hydrogel skeleton, and it endowed the hydrogel with intelligent thermal sensitivity. Core-shell nanoparticles (NPs) with well-controlled sizes were synthesized through reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization. The NPs served as dynamic cross-linking cores and greatly improved the adhesion and mechanical properties of the hydrogel. In particular, the adhesive strength of PNIPAM-PDA-NP hydrogel on PTFE reached 10.3 kPa, and the maximum compressive strength was measured to be 3.41 MPa when being compressed by 90% of its volume. This study provides a novel strategy to develop high-performance stimuli-responsive adhesive hydrogels.