Synthesis and characterization of barnacle adhesive mimetic towards underwater adhesion

A polyacrylamide including tetra-alanine units, hydroxy groups, and hexyl groups was synthesized as a mimetic of barnacle underwater adhesive proteins. The synthesized barnacle mimetic polymer was dissolved in water and subjected to a condensation reaction with hexylamine. Gelation through multiple hydrogen bonds of the oligo-alanine units was confirmed. The adhesive strength of the bonded substrate with the gel-forming barnacle mimetic polymer solution was demonstrated to be 402 kPa for poly(methyl methacrylate) (PMMA) plate adhesion by the tensile shear adhesion test.