Highly Anisotropic Rigidity of “Ribbon-Like" Polymers: III. Phase Diagrams for Solutions

The behavior of solutions of polymer chains with anisotropic rigidity is considered theoretically. The diagrams of different scaling regimes and the phase diagrams for polymers with arbitrary contour length L, inplane rigidity l, and out of plane rigidity l2 are obtained. Two new types of nematic structures in addition to ordinary nematic with ordering of tangent vectors are found for the regime of moderate second rigidity $l_2~(l \lesssim l_2 \lesssim l^3/d^2 )$: a pancake nematic (with ordering of the normals to the planes of main flexibility of the chains) and a biaxial nematic (when both tangent and normal vectors are ordered). We also found smectic A and smectic C phases in addition to three nematic phases. The scaling (modified blob) and mean-field with correlation corrections approaches are developed and used when appropriate. Order parameters, correlation radii and chain sizes are discussed for most of the regimes