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Phase separation of asymmetric diblock copolymer near surfaces in selective solvents is theoretically investigated by using the real-space version of self-consistent field theory (SCFT). Several morphologies are predicted and the phase diagram is constructed by varying the distance between two parallel hard surfaces (or the film thickness) W and the block copolymer concentration fP. Morphologies of the diblock copolymer in dilute solution are found to change significantly with different film thicknesses. In confined systems, stable morphologies found in the bulk solution become unstable due to the loss of polymer conformation entropy. The vesicle phase region contracts when the repulsive interaction between the blocks is strong (strong segregation regime). The mixture of vesicles, rodlike and spherelike micelles and the mixture of vesicles and sphere-like micelles disappear in contrast to the weakly segregating regime. The walls strongly affect the phase separation of block copolymer in selective solvent, and the depletion layer near the surface contributes much to the micelle formation of the block copolymer. Interestingly, the self-assembled morphologies stay near the walls with the distance on the order of the radius of gyration of the block copolymer. The oscillation of the polymer distribution near the walls allows the surface phase separation to be observed due to the strong repulsion between the blocks A and B. [ABSTRACT FROM AUTHOR]

We investigated how very strong confinement, smaller than the polymer persistence length lp, affects the isotropic-nematic transition for semiflexible polymer solutions using GPU-accelerated Langevin dynamics. Walls facilitate polymer alignment, and under strong quasi-two-dimensional slitlike confinement, the I-N transition is found to be a continuous transition occurring via capillary nematization. We found that the I-N transition in the slit is a second-order transition, and the transition volume fraction ϕcr decreases with decrease of the slit height H. For H > lp, the critical exponent of the order parameter is found to be β ≈ 0.3-0.5. β sharply increases for H higher than a critical height, indicating the onset of a different wall-induced phase transition. Higher ϕcr are found for larger H, which is associated with increased monomer packing near the walls and correspond to the partial wetting transition predicted by self-consistent field theory. [ABSTRACT FROM AUTHOR]