Polymerization-induced self-assembly (pisa) generated cholesterol-based block copolymer nano-objects in a nonpolar solvent: combined experimental and simulation study.

Abstract

A family of nanostructured morphologies made of poly(cholesteroyl methacrylate)-b-poly(styrene) (PCMA-b-PS) copolymers were prepared via reversible addition–fragmentation chain transfer (RAFT) dispersion. The number-average degree of polymerization (DPn) of the PS segment was targeted from 15 to 150 to obtain spherical, wormlike, fibrillar, and vesicular nano-objects as evidenced from field emission scanning electron microscopy and transmission electron microscopy, supported by dynamic light scattering experiments. Numerous morphologies were also observed by increasing the total solid content (5–25 wt %) of the copolymer. Thermoreversible gel–sol transition was studied with a higher wt % of copolymers. The experimental observations were further supported by computer simulations using dissipative particle dynamics. The developed coarse-grain model, accounting for both the graft architecture and structural heterogeneity of the lyophilic block, made it possible to evaluate the morphological transitions in a block copolymer solution at different block length ratios, different total solid contents, and temperatures to provide an in-depth understanding of the experimental results.