Abstract
The micro-phase separated structures of ABA triblock copolymers comprising flexible amorphous poly(methacrylate) (PMA, A block) and semiflexible liquid crystalline (LC) polyester (B block) with amorphous block volume fractions (ϕam) ranging from 0.2 to 0.8 were investigated. For ϕam < 0.52, block copolymers formed lamellar microdomains. The LC segments extended perpendicular to the interface and formed smectic layers parallel to the lamellae. The segments folded within the lamellae, whereas the amorphous segments had dimensions similar to those of in amorphous block copolymers. When ϕam > 0.68, the LC lamellae divided into cubes, transforming into spheres in the PMA matrix. Our results demonstrate that flexible-semiflexible-flexible block copolymers can change their morphology characteristically by the contour length and flexibility of the semiflexible segment in addition to other factors known for flexible copolymers.
