POS4-0788
Solvent-selectivity-driven core/corona inversion in stereoregular PLLA-b-PS block copolymer micelles
Topic
S4. Colloids, Interfaces, and Molecular Assemblies for Functional Soft Materials
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
Daung Jeon (Korea Advanced Institute of Science and Technology)
Co-Author(s)
Abstract
Block copolymer (BCP) self-assembly is a powerful strategy for generating nanostructured soft materials. Although block composition readily controls micelle morphology, selective placement of individual blocks within the core or corona remains challenging. It often requires additional surfactants or new molecular design.
Herein, we report a surfactant-free strategy for controlling both morphology and internal architecture using poly(L-lactide)-block-polystyrene (PLLA-b-PS), a crystalline–coil block copolymer. It is synthesized by ring-opening polymerization and RAFT polymerization. Block composition and solvent selectivity served as orthogonal parameters governing self-assembly. In PLLA-selective acetonitrile, PLLA-b-PS formed micelles with a PS core and PLLA corona, while decreasing the PLLA volume fraction induced a transition from spheres to worm-like cylinders and vesicles. In contrast, PS-selective cyclohexane generated inverted assemblies with a crystalline PLLA core, whereas dichloromethane acted as a non-selective solvent in which the copolymer remained molecularly dissolved. These results highlight solvent selectivity as a simple means of controlling both assembly morphology and core–corona placement. Furthermore, with the stereoregular PLLA block, all assemblies exhibited intrinsic chiroptical activity. Circular dichroism spectra showed a band near 210 nm that was largely independent of assembly morphology and internal structure, indicating that the intrinsic chiroptical response remains robust and independent of the surrounding supramolecular environment. Importantly, this structural independence demonstrates that the stereoregular PLLA blocks provide a stable chiral platform, preserving their chiroptical integrity across diverse morphologic states. This work establishes solvent selectivity as a tool for engineering stereoregular BCPs and opens up new avenues for environmentally stable chiral nanomaterials.
Herein, we report a surfactant-free strategy for controlling both morphology and internal architecture using poly(L-lactide)-block-polystyrene (PLLA-b-PS), a crystalline–coil block copolymer. It is synthesized by ring-opening polymerization and RAFT polymerization. Block composition and solvent selectivity served as orthogonal parameters governing self-assembly. In PLLA-selective acetonitrile, PLLA-b-PS formed micelles with a PS core and PLLA corona, while decreasing the PLLA volume fraction induced a transition from spheres to worm-like cylinders and vesicles. In contrast, PS-selective cyclohexane generated inverted assemblies with a crystalline PLLA core, whereas dichloromethane acted as a non-selective solvent in which the copolymer remained molecularly dissolved. These results highlight solvent selectivity as a simple means of controlling both assembly morphology and core–corona placement. Furthermore, with the stereoregular PLLA block, all assemblies exhibited intrinsic chiroptical activity. Circular dichroism spectra showed a band near 210 nm that was largely independent of assembly morphology and internal structure, indicating that the intrinsic chiroptical response remains robust and independent of the surrounding supramolecular environment. Importantly, this structural independence demonstrates that the stereoregular PLLA blocks provide a stable chiral platform, preserving their chiroptical integrity across diverse morphologic states. This work establishes solvent selectivity as a tool for engineering stereoregular BCPs and opens up new avenues for environmentally stable chiral nanomaterials.
