Mussel-inspired hybrid network hydrogel for continuous adhesion in water
Mussel-inspired catechol-based strategy has been widely used in development of adhesives. However, the properties of the adhesives were still severely limited in a humid environment, especially in water. In this work, a facile and versatile approach was proposed to prepare an underwater adhesion hydrogel. First, dopamine (DA) was grafted to oxidized carboxymethylcellulose (OCMC) to obtain dopamine-grafted oxidized carboxymethylcellulose (OCMC-DA). Second, the acrylamide (AM) monomer is conjugated with OCMC-DA by Schiff base reaction, and then polymerized to form OCMC-DA/PAM hydrogel. The properties of resulting hydrogel have been fully characterized. The underwater adhesion strength of the hydrogel can reach as high as 86.3KPa and reduced to 43KPa after immersed in water for 9 days. More remarkably, we found the maximal adhesion strength was shown when the hydrogel reaches a balance between the storage modulus and loss modulus. Moreover, we demonstrate the mechanical properties of our fabricated hydrogel by compressive test and rheological analysis. The adhesive hydrogel also has excellent biocompatibility.