Controllable and facile synthesis of poly(2-oxazoline)s using trimethylsilyl trifluoromethanesulfonate as the initiator

Poly(2-oxazoline)s have received more and more attention in biomedical fields for their hydrophilicity and excellent biocompatibility. Poly(2-oxazoline)s can act as functional peptide mimics and promising substitutes for polyethylene glycol. Therefore, it is of great importance to develop new polymerization methods for the synthesis of functional poly(2-oxazoline)s with diverse structures. Herein, we report a controllable and facile synthesis of poly(2-oxazoline)s using trimethylsilyl trifluoromethanesulfonate (TMSOTf) as the initiator. This polymerization presents temperature-dependent characteristics, showing a decrease in polymerization time from a week to hours by increasing the reaction temperature. Based on TMSOTf-initiated polymerization, poly(2-oxazoline)s were obtained in a controllable way with expected chain length, variable side chain functional groups and narrow dispersities. This living polymerization on 2-oxazolines also enables facile synthesis of statistical and block copolymers of poly(2-oxazoline) and will contribute to the functional study and application of poly(2-oxazoline).