High-density network antiswelling hydrogel with confined crystallization mediated by bacterial cellulose and reverse dialysis.

Hydrogels, a typical solid-liquid hybrid material, have shown great potential in wearable electronics, tissue engineering, and other fields; however, their underwater applications have long been limited by the 'swelling-weakening 'effect. To address this challenge, this study proposes a 'bacterial cellulose (BC) synergistic reverse -dialysis-induced confined dense network 'strategy to construct a BP-RD hydrogel with high water content and excellent mechanical-functional properties through a one-step approach. The design innovatively uses the reverse dialysis process to drive dual dynamic assembly. First, polyethylene glycol-mediated water extraction compresses the BC network to form a rigid confined space. Then, polyvinyl alcohol molecules move and crystallize in the BC framework, creating a dense interpenetrating network. At 75% moisture content, the material achieved 22 MPa fracture strength, 145 MJ m-3 toughness, and 1.58 S m-1 conductivity owing to the confinement effect. Additionally, it showed outstanding antiswelling characteristics (the tensile strength increased by 14% after 7 days). This method can also be applied to combine existing hydrogels in one step, creating a double-layer hydrogel structure with improved mechanical properties and swelling performance. This approach solves the key problems of the failure of traditional hydrogels to expand, the cumbersome preparation process, and the difficulty in meeting the performance requirements of multiple scenarios.