Isotropic-nematic interface in a lyotropic system of wormlike chains with the Onsager interaction

The effects of the flexibility of constituent wormlike chains on the interfacial properties between isotropic and nematic phases are investigated in a self-consistent mean-field approximation. The model is built from a wormlike chain formalism which crosses over from the rod limit to the flexible limit, and the Onsager-type interaction which describes the orientation-dependent repulsive interaction. Physical properties such as the surface tension, interfacial width, and density- and order-parameter profiles are numerically calculated as functions of varying flexibility (defined as the ratio between the total polymer length and the persistent length) and tilt angle (defined as the angle between the interfacial normal and the nematic director in the nematic phase). The resulting modified diffusion equation is numerically solved by using a combination of the Crank-Nicolson algorithm and SPHEREPACK, a software package that deals with the analysis and synthesis of spherical-harmonics functions.