A "Click" strategy for tuning in situ the hydrophilic-hydrophobic balance of AB macrosurfactants

The self-organization of amphiphilic block copolymers in water strongly depends on their molecular structure, in particular on their hydrophilic-hydrophobic balance. Herein, a simple method for tuning the amphiphilicity of polymeric macrosurfactants in aqueous medium is proposed. This concept relies on the "click" ligation of an amphiphilic block copolymer (AB type) and a hydrophilic homopolymer (B type). In the present communication, the validity of this approach was examined with model polymers based on polystyrene (PS) and poly[oligo (ethylene glycol) acrylate] (POEGA) segments. A well-defined omega-azido functional diblock copolymer PS-b-POEGA and an alpha-alkyne functional homopolymer POEGA were prepared using atom transfer radical polymerization. These two polymers could be efficiently coupled to each other via copper-catalyzed azide-alkyne click chemistry in aqueous medium. Moreover, in this coupling strategy, an ester group was introduced at the junction between AB and B segments. This labile moiety may be "cut" by hydrolysis.