Tri-network, physical cross-linked sodium alginate hydrogel with strongly self-healing capacity and highly tough, for wearable flexible devices

Physical cross-linked hydrogels offer advantageous self-healing and easy preparation for broad application in wearable flexible devices. However, compared to chemical crosslinking, physical crosslinking is relatively fragile, yielding weak mechanical properties that hinder further development. To solve this problem, we polymerized [2-(methacryloyloxy)ethyl]dimethyl-(propyl3-sulfonate) ammonium hydroxide (DMAPS) into SA-PMAA hydrogels to form a three-network physical cross-linked hydrogel with high strength and superior self-healing ability. PDMAPS possesses dipolar-dipole action between lateral base units and self-associating ability. By introducing PDMAPS into the SA-PMAA double network structure, we created a hydrogel with excellent self-healing properties and mechanical strength. The hydrogel boasts a mechanical strength of 41 KPa, a maximum elongation at break of 820 %, and 94.7 % self-healing efficiency after 12 h, surpassing most hydrogels. With its polar groups, the hydrogel offers great compatibility with most aqueous slurries containing inorganic fillers, making it a material with immense potential as a polyelectrolyte and broad applications in the field of biosensing and wearable flexible devices.