Tough adhesion with a tough gel and chitosan bridging polymer

Abstract

The present disclosure shows that by combining pH-responsive bridging chitosan polymer chains and a tough hydrogel dissipative matrix one can achieve unprecedented ultra-tough adhesion to tissues (>2000J/m2) in 5-10 mins without covalent bond formation. The strong non-covalent adhesion was shown to be stable under physiologically relevant conditions and strongly influenced by chitosan molecular weight. molecular weight of polymers in the matrix, and pH. The adhesion mechanism relies primarily on the topological entanglement between the chitosan chains and the permeable adherends. The present disclosure also discloses dry polymer films to generate instant adhesion between hydrogel-hydrogel and hydrogel-elastomer surfaces. Unprecedented adhesive energies (>3000J/m2) between alginate-polyacrylamide tough hydrogels were achieved instantaneously using an intermediate chitosan film, governed by pH change, H-bonding, and bridging polymer entanglement. Furthermore, this strategy also generates instant strong adhesion between acrylic elastomers and tough hydrogels with adhesion energy as high as 4000J/m2.

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