POS4-0458
Revealing Hidden Confinement-Induced Packing Transitions in Spherical Block Copolymer Thin Films by Suppressing Terracing
Topic
S4. Colloids, Interfaces, and Molecular Assemblies for Functional Soft Materials
When and Where
Sep 30, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Heesuk KIM
Jinhye BAE
Presenter(s)
Sung Kwan Tae (Department of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea)
Co-Author(s)
Abstract
Confinement-induced packing transitions of spherical particles have been extensively studied in colloidal systems. Sphere-forming block copolymers in thin films constitute a similarly confined particulate system, where finite film thickness can generate structural frustration and induce comparable lattice transitions. However, unlike hard-sphere colloidal systems, polymer chain mobility allows block copolymer thin films to relax this frustration through terracing, an energetically favorable pathway that prevents such packing transitions.
Here, we show that core crosslinking of spherical block copolymer domains suppresses terracing during solvent vapor annealing, thereby enabling structural reorganization that would otherwise be inaccessible. Starting from thermally annealed hexagonally packed monolayers, controlled swelling of core-crosslinked films drives structural evolution from hexagonal monolayers to square bilayers, then to hexagonal bilayers, analogous to transitions reported in confined colloidal systems. Addition of a short homopolymer further improves ordering of the square bilayer phase, suggesting that its formation is not solely a consequence of kinetic trapping. These results demonstrate that suppression of terracing enables direct observation of hidden packing transitions in block copolymer thin films and provides a platform for studying structural organization in confined particulate systems.
Here, we show that core crosslinking of spherical block copolymer domains suppresses terracing during solvent vapor annealing, thereby enabling structural reorganization that would otherwise be inaccessible. Starting from thermally annealed hexagonally packed monolayers, controlled swelling of core-crosslinked films drives structural evolution from hexagonal monolayers to square bilayers, then to hexagonal bilayers, analogous to transitions reported in confined colloidal systems. Addition of a short homopolymer further improves ordering of the square bilayer phase, suggesting that its formation is not solely a consequence of kinetic trapping. These results demonstrate that suppression of terracing enables direct observation of hidden packing transitions in block copolymer thin films and provides a platform for studying structural organization in confined particulate systems.
