Novel amphiphilic self-healing coatings
A series of well-designed amphiphilic block copolymer polydimethylsiloxane-poly(2-(dimethylamino) ethyl methacrylate) (PDMS-PDMAEMA) synthesised by atom transfer radical polymerisation was introduced to the self-healing polydimethylsiloxane-based polyurethane (PDMS-PU) system, which was further zwitterionised during solidification. The slight swelling resulting from zwitterionic segments promoted the contact fusion rate of the mechanically damaged parts, which improved the underwater self-healing ability of the resulting coating. The PDMS segments in both amphiphilic polymer and PU were entangled with each other to form a semi-interpenetrating network while the zwitterionic segments migrated externally when being immersed underwater, thus a micro-phase separation structure was obtained for antifouling coating.
Qualitative and quantitative tests have proved that the coating can significantly resist the adhesion of proteins (156 μg/cm2 vs 14 μg/cm2) and marine microorganisms (425 × 103 n/cm2 vs 12 × 103 n/cm2). In addition, the organically modified montmorillonite (MMT) effectively improved the coating’s mechanical properties via coordination bonding, as the resulting coating’s fracture strength was increased by 50 % compared with the initial PU coating. According to the researchers, they have solved an inherent problem in underwater self-healing antifouling coatings – that is to achieve self-healing properties without loss of mechanical properties, which provides inspiration for the research and development of novel self-healing antifouling coatings.
The study has been published in Progress in Organic Coatings, Volume 175, February 2023.