Phase behavior of semiflexible-coil diblock copolymers : a hybrid numerical SCFT approach

The phase behavior of semiflexible-coil diblock copolymer melts is studied by solving the self-consistent field theory (SCFT) equations of wormlike chains. Significant improvement of numerical accuracy and stability is achieved by a hybrid numerical implementation of SCFT, in which the space-dependent functions are treated using a spectral method and the orientation-dependent functions are discretized on a unit sphere (3D Euclidean space) with an icosahedron triangular mesh. The angular Laplacian is solved in real-space using a finite volume algorithm. Phase diagrams of the model system are constructed from SCFT. Phase transitions between various smectic phases such as monolayer and bilayer smectic-A, monolayer and bilayer smectic-C, as well as folded smectic phases, are predicted. In particular, the stability of the monolayer and bilayer smectic phases is associated with the competition between interfacial energy and coil-stretching entropy, which strongly depends on the interplay between orientational interaction and microphase separation and the topological disparity between the semiflexible and coil blocks.