POS2-0377
Effect of Terminal-Group Compatibility on Chain Stretching and Self-Assembled Morphologies in Block Copolymers
Topic
S2. High-End Characterization/Polymer Physics/Properties
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
Namjun Kim (Pohang University of Science and Technology)
Co-Author(s)
Abstract
Block copolymer self-assembly is generally described by the Flory-Huggins interaction parameter (χ), the degree of polymerization (N), and the volume fraction of each block (f). However, recent experimental and theoretic studies indicate that even subtle modifications to the terminal groups of block copolymers can markedly influence their equilibrium nanostructures. In this study, we investigate the role of terminal-group compatibility in regulating chain conformation, self-assembled morphology, and rheological behavior in block copolymers. A set of six polyisoprene-b-poly(ethylene oxide) (PI-b-PEO) block copolymers with two block compositions and three different terminal-group combinations was synthesized. For PI-b-PEO with a symmetric composition, incorporating hydroxyl end groups at the PI block induced a transition from lamellar to hexagonally packed cylinders, accompanied by a pronounced reduction in domain spacing, attributed to contraction of the PI block. An analogous trend was observed for PI-b-PEO with an asymmetric composition, where the hexagonal morphology was retained but substantial shrinkage of the PI domains occurred. Compared with PI-b-PEO bearing sec-butyl termini at the PI block, these samples exhibited suppressed PEO crystallinity and markedly enhanced elastic responses above the PEO melting temperature, which can be attributed to OH–OH clustering acting as physical crosslinks under nanoconfinements.
