In situ generation of zwitterionic-functionalized liquid metal-based polydimethylsiloxane antifouling coatings with self-healing ability

Predicated on the marine bio-adhesion strategy, we herein assembled tannic acid (TA) in-situ onto Gallium-based liquid metal (GLM) nanodroplets surface effectuating the formation of poly(TA/PEI) adhesive layer with poly-ethyleneimine (PEI) via Schiff-base reaction and/or Michael addition to derive poly(TA/PEI)-functionalized GLM nanodroplets (GLM-PEI). Subsequently, the zwitterionic precursor triisopropylsilyl methacrylate (TISM) was bonded with the amine group of poly(TA/PEI) through aza-Michael addition for extracting TISM-functionalized GLM nanodroplets (GLM-TISM). The on-site hydrolysis of the as-prepared GLM-TISM into a zwitterionic group could be achieved by placing the zwitterionic precursor triisopropylsilyl TISM in an aqueous environment. Therefore, the synergy created by the bactericidal activity of GLM nanodroplets along with the strong surface hydration of the zwitterionic group contributes towards the remarkable antifouling performance of the GLM-TISM, which exhibits good dispersibility in polydimethylsiloxane (PDMS) elastomer coating and as functional filler to fabricate nano-composite coatings (PDMS@GLM-TISM). The as-obtained PDMS@GLM-TISM demon-strate excellent antifouling effect with the inhibition of bacterial and algae adhesion (removal of more than 96 % of bacteria and 77 % of algae) under the synergistic effect of liquid metal and zwitterionic groups. Furthermore, GLM-TISM nanodroplets can furnish the PDMS coating with self-repair ability by crosslinking the unreacted vinyl monomer of PDMS with the exposure to GLM to initiate polymerization.