Polysaccharide-templated preparation of mechanically-tough, conductive and self-healing hydrogels

Self-healing hydrogels possess the capability to repair themselves after mechanical damage, but their applications are often severely limited by their weak mechanical strengths or poor healing efficiencies. To obtain the self-healing hydrogels with high performances, a linear polysaccharide template with aldehyde groups was introduced in the gelation process. The polysaccharide template (oxidized sodium alginate, OSA) can conjugate with acrylamide (AM) monomer via Schiff base reaction. The radical polymerization between double bonds in the side chains of OSA and free AM monomer results in the formation of OSA-poly(acrylamide) (OSA-PAM) hydrogels. The synergistic effect of dynamic Schiff base and hydrogen bonding interactions between OSA and PAM chains endows the OSA-PAM hydrogels with excellent self-healing and mechanical properties. The resulting OSA-PAM hydrogels also exhibit controllable conductivity and stretch sensitivity. The self-healing, mechanically tough and conductive OSA-PAM hydrogels could have potential applications in artificial skins, robotic actuators and medical devices.