Modulation of polymerization rate of N-carboxyanhydrides in a biphasic system

Abstract

The recent advances in accelerated polymerization of N-carboxyanhydrides (NCAs) offer an effective strategy to simplify the preparation of polypeptide materials. However, the fine-tuning of polymerization kinetics, which is critical to differentiate the main polymerization and the side reactions, remains largely unexplored. Herein we report the modulation of polymerization rate of NCA in a water/oil biphasic system. By altering the aqueous pH, the initial location of the initiators, and the pKa of initiating amines, we observed the change in polymerization time from several minutes to a few hours. Due to the high interfacial activity and low pKa value, controlled polymerization was observed from multi-amine initiators even if they were initially located in the aqueous phase. This work not only improves our understanding on the biphasic polymerization mechanism, but also facilitates preparation of versatile polypeptide materials.