NANOSTRUCTURED BLOCK COPOLYMER COATINGS WITH INSPIRATION FROM BIOLOGY: TAKING ADVANTAGE OF HYDROGEN BONDING AND ELECTROSTATIC INTERACTIONS

摘要

The synthesis of polymers with non-covalent interactions, including electrostatic interactions and hydrogen bonds, in polymer main chains and side chains receives increasing interests in recent years. 1,2 The unique properties of those polymers, such as stimuli responsiveness, tailored thermal and mechanical properties have been well studied, but their self-repair capacities have not been deeply exploited.3,4 Polymers being fatigued may contain micro-cracks, which reduce mechanical properties. Healing will enable the polymers with longer lifetimes and less maintenance. The common healing methods are either thermal treatment or solvent process.5 Recently a novel method was introduced by White et al. achieving automatically healing by imbedding microencapsulated healing agents and a catalytic chemical trigger in polymer matrix to make up cracks by polymerization.6 The method has some limitations, such as the stability of catalyst to environmental conditions and the exhaustion of healing agents. Polymers assembled via non-covalent interactions are thermally stable yet kinetically labile allowing the system to repair repeatedly. Here we introduce both hydrogen bonds and electrostatic interactions to copolymers to achieve repeated healing at mild conditions. The focus of this paper is the synthesis of these novel block copolymers with ionic sites introduced via complementary nucleobased hydrogen bonds.