Shifting the Isotropic–Nematic Transition in Very Strongly Confined Semiflexible Polymer Solutions

Abstract

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.