The Effect of Side-Chain Modification via Hydrogen Bonding on the Microphase-Separated Structure of PS-<i>b</i>-P4VP-<i>b</i>-PMMA

Block copolymers can self-assemble into various microscopic structures, making them highly promising for industrial applications. For block copolymer applications, it is essential to control the microphase-separated structures and the periodic length precisely. Side chain modification is one of the effective and straightforward strategies to control morphology. In this study, PS-b-P4VP-b-PMMA was synthesized via living anionic polymerization, and partial modification of the polymer chain was achieved through hydrogen bonding between 4-vinylpyridine and carboxylic acids. Small-angle X-ray scattering (SAXS) measurements revealed that the sample, which exhibited a disordered state without introducing carboxylic acid, formed a lamellar structure with a d-spacing of 20.2 nm upon addition of the acid. Moreover, the d-spacing varied depending on the type of carboxylic acid. These results suggest that hydrogen bonding interactions between P4VP and dicarboxylic acids play a crucial role in inducing microphase separation.