Linear Amphiphilic Polyglycidol/Poly(ε-caprolactone) Block Copolymers Prepared via Click Chemistry-Based Concept

We introduce a click chemistry-based concept for the preparation of amphiphilic block copolymers comprising linear polyglycidol (PG). Herein, a new class of linear polyglycidol/poly(epsilon-caprolactone) (PG/PCL) block copolymers of precisely designed macromolecular characteristics and composition was synthesized to demonstrate the convenience of this strategy. Monohydroxyl poly(ethoxyethylglycidyl ether) (PEEGE) precursors were synthesized by ring-opening anionic polymerization of ethoxyethylglycidyl ether (EEGE) and subsequently functionalized with a clickable alkyne end group. In parallel, a bifunctional PCL diol was modified to an azide-terminated macroreagent. PG/PCL block copolymers were obtained by click coupling reaction of the alkyn- and azide-functional macroreagents in the presence of a CuBr/PMDETA catalytic complex and subsequent cleavage of the protective ethoxyethyl groups of PEEGE. The amphiphilic block copolymers were not directly soluble in water, and defined nano-sized micelles were obtained via the solvent evaporation method. The synthesis pathway described here can be extended toward synthesis of various functional block copolymers comprising linear PG.