A new lamellar morphology of a hybrid amorphous/liquid crystalline block copolymer film

We study the morphology of a thin film made of a hybrid amorphous/side chain liquid crystalline diblock copolymer, in which the amorphous polymer is similar to the backbone of the liquid crystalline polymer. Microphase separation in the smectic A phase leads to a terraced film made of alternating amorphous and smectic layers, both parallel to the substrate. This new lamellar morphology differs from the bulk ordering where minimization of the block-block interfacial energy results in an orthogonal arrangement. We discuss the stability of such a lamellar structure in the film by considering the influence of the surface field on the internal diblock specific interactions.