Inspired by mussel: biomimetic polyelectrolyte complex coacervate adhesive initiates a connection through water exchange

Here the authors report a versatile and strong underwater adhesive that was inspired by the chemical features of mussel foot proteins. A random copolymer (poly(N-(3,4-dihydroxyphenethyl)methacrylamide-co-methacryloxyethyltrimethyl ammonium chloride-co-acrylamide) (PDMA)–Tf₂N) was prepared that contained side-chain catechol groups and quaternary ammonium cations that were ion-paired with bis(trifluoromethane-sulfonyl)imide anion (Tf₂N⁻). After dissolving PDMA–Tf₂N and poly(acrylic acid) in dimethyl sulfoxide, a polyelectrolyte complex coacervate adhesive (P2) could be formed, which could be triggered through solvent exchange. P2 exhibited outstanding underwater shear strength to various substrate surfaces. After a critical curing time (t _s = 10 min), the adhesion strength of P2 to glass increased sharply up to 187.298 kPa (t _s = 40 min).