Exact banded patterns from a Doi-Marrucci-Greco model of nematic liquid crystal polymers

Elements of pattern formation in nematic liquid crystal polymers are presen ted using the Doi-Marrucci-Greco (DMG) moment-averaged theory. The theory y ields a full tensor orientation equation, accounting for excluded-volume an d distortional elasticity potentials, with rotational molecular diffusion. Spinodal decomposition associated with unstable homogeneous phases is descr ibed first by way of an exact solution of the linearized DMG model. A varie ty of uniaxial and biaxial banded spatial patterns are then explicitly cons tructed from the DMG model. Exact solutions are given that possess order pa rameter spatial variations as well as solutions whose banded intensity patt erns arise from sinuous director heterogeneity. These constructions pose as analytical models for banded structures observed during and after cessatio n of simple shear or elongation.