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

We investigated how very strong confinement, smaller than the polymer persistence length l(p), 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 phi(cr) decreases with decrease of the slit height H. For H < l(p), the critical exponent of the order parameter is found to be beta approximate to 0.3-0.5. beta sharply increases for H higher than a critical height, indicating the onset of a different wall-induced phase transition. Higher phi(cr) 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.