Mussel-Inspired Multifunctional Hydrogel Based On Supramolecular Interactions

In this paper,a simple strategy is provided to construct novel multifunctional hydrogels with shape memory?self-healing and adhesive properties via mussel inspired chemistry and supramolecular interactions.Firstly,Alg-PBA and Alg-DA were prepared by grafting 3-aminophenylboronic acid?PBA?and dopamine?DOPA?onto sodium alginate?Alg?respectively.According to the analysis of 1H NMR and UV-vis,the content of functional groups were calculated to be 21% and 17% respectively.The supramolecular hydrogel was prepared by mixing the Alg-PBA and Alg-DA in alkaline condition because of the p H responsiveness of PBA group.The interaction between Ca²⁺ and Alg was introduced to the hydrogel system as the second supramolecular crosslinking network.The shape memory behavior of the hydrogel was endowed by double supramolecular interactions.The original shape was formed by coordination interaction meanwhile the dynamic PBA-diol ester bonds served as temporary cross-links and stabilized the deformed shape of the hydrogel,thereby contributing to the pH responsive shape memory behavior.In addition,the interaction between Ca²⁺ and Alg could also play the role of temporary cross-links.Ca²⁺ could be extracted by EDTA·2Na,resulting in the recovery of original shape.The hydrogel possessed self-healing capacity due to the dynamic nature of PBA-diol ester bonds.The destructed hydrogel could be healed autonomously in 20 s.The self-healing behavior of the supramolecular hydrogel was further evaluated by rheological measurement.The self-healing process could be repeated at least three times without the decrease of mechanical properties.In addition,the oxidized Alg-PBA/Alg-DA hydrogel and Alg-PBA/Alg-DA/Ca²⁺ hydrogel showed the self-healing performance too.Finally,dopamine derivatives endowed the hydrogel adhesive properties which could be proved by weight experiment.