Liquid Crystal Block Copolymers With Side‐On Mesogens: Orientation of Liquid Crystals at Microdomain Boundaries and Core–Shell Structure Formation

ABSTRACT P n ‐ M n,am ‐ φ LC block copolymers, composed of a side‐on side‐chain liquid crystal (LC) block and an amorphous poly(butyl methacrylate) (PBMA) block, were investigated to elucidate their microphase‐separated morphology and LC orientation at the phase boundary. The LC block, at volume fractions φ LC = 24%–70%, contains mesogens laterally attached via spacers of length n = 6–12. When φ LC exceeds 50%, lamellar microdomains form and gradually transform into PBMA‐cylinder microdomains. LC director orientation depends on n : perpendicular alignment occurs at n = 6 and 8, while parallel alignment appears at n = 10 and 12. At φ LC below 40%, core–shell microdomains emerge, featuring a PBMA core and LC shell within a PBMA matrix. This morphology results from volume and backbone length imbalance, and chain conformation asymmetry. Although the LC block has a shorter contour length than PBMA, it occupies a larger volume due to its high molecular weight. The LC block stretches along the normal to the microdomain boundary, while the PBMA block adopts a slightly elongated random‐coil conformation. These findings demonstrate that side‐on side‐chain LC blocks enable systematic control over microdomain morphology and LC orientation by tuning molecular parameters, offering insights for designing nanostructured materials.