Mechanically robust gluconate-regulated polydopamine–polyacrylamide hydrogels with exceptional adhesion

Abstract

Achieving intrinsic conductivity, excellent mechanical properties, and self-adhesiveness simultaneously in a stretchable ionic hydrogel is critical for the development of ionotronic applications, yet obtaining these properties in a single hydrogel continues to be a major hurdle in the field. Here, gluconate-regulated polydopamine–polyacrylamide hydrogels (PDA–PAM–X) are developed to simultaneously improve the mechanical robustness, self-adhesion, and ionic conductivity of PDA–PAM. The gluconate induces the formation of a dynamic crosslinked structure that strengthens the mechanical properties and provides high ionic conductivity, whereas the dopamine endows hydrogels with self-adhesive properties. Based on these integrated effects, the optimized zinc gluconate-regulated polydopamine–polyacrylamide hydrogel (PDA–PAM–Zn) exhibits a 75.04% enhancement in the mechanical strength (59.5 kPa) whilst also demonstrating a toughness of 198.84 kJ m⁻³, a Young's modulus of 19.351 kPa, and an ionic conductivity of 2.05 S m⁻¹. Furthermore, the PDA–PAM–Zn hydrogel exhibits strong adhesion to various substrates (plastics, metals, glass).