ROPISA of salicylic acid O-carboxyanhydride: fast polymerization followed by in situ kinetics-driven self-assembly

Abstract

Polymerization-induced self-assembly (PISA) has become a significant technique for creating well-defined block copolymer nanoparticles. However, synthesis of biocompatible and degradable nanoparticles using one-pot scalable chemistry through PISA is rarely reported due to the solubility flipping requirement before and after polymerization. In this study, we present the ring opening polymerization-induced self-assembly (ROPISA) of poly(ethylene glycol)-poly(salicylic acid) (mPEG-PSA, molecular weight of mPEG is 5 kDa) block copolymers into high-order nanostructures in tetrahydrofuran (THF). The ROPISA involves the fast ROP of salicylic acid O-carboxyanhydride (SAOCA) in minutes followed by in situ slow self-assembly, resulting in a non-equilibrium assembly process. The self-assembly mechanism is analysed by transmission electron microscopy and turbidity studies, revealing that the self-assembly process is dependent on the structure and the solid content of the PSA block. This kinetics-driven assembly enables worm-like structures desirable for biomedical applications.