Synthesis and properties of helical polystyrene derivatives with amino acid side groups

Abstract

A series of polystyrene derivatives with chiral amide groups with a controlled molecular weight and narrow molecular weight distribution were synthesized by reversible addition–fragmentation chain transfer (RAFT) radical polymerization. These polymers adopted a stable helical conformation due to intramolecular hydrogen bonding between adjacent repeat units. Experiments showed that the helical conformation of the polymer was more stable at higher molecular weights and lower temperatures, and in low-polarity solvents. Block copolymers containing poly(ethylene oxide) (PEO) and helical polystyrene were crosslinked with ethylene glycol dimethacrylate during polymerization-induced self-assembly (PISA) to obtain uniformly-sized vesicular nanoparticles and linear single-handed helical nanofibers. Interestingly, the helicity, average width, and helical spacing of the nanofibers were altered after PISA. This study explored the synthesis of vinyl polymers with a stable helical conformation and provides a method to obtain vesicular nanoparticles with complex morphologies and nanofibers with helical conformations.