Amphiphilic block copolymer with diazonium salt pendant groups: Synthesis, self-assembly and post-modification

In this work, an amphiphilic block copolymer (PS-b-PSN2+) composed of PS and PS-based polymeric diazonium salts was synthesized. The diblock precursor polymer (PS-b-PSNHBoc) consisting of PS block and Boc-protected poly(p-vinylaniline) block was prepared by RAFT polymerization. After the deprotection and diazotization, an amphiphilic block copolymer with diazonium salt pendant groups was obtained. The block ionomer would then self-assemble into nano-sized micelles in selective solvents, which was verified by TEM and dynamic light scattering measurements. The diazonium groups in the corona of the polymeric micelles could not only serve as the major role for colloidal stability but also allow an efficient post-modification. Azobenzene moieties could be easily introduced into the self-assembled micelles by azo coupling reaction between the polymeric diazonium salts and N,N-dimethylaniline.