ANISOTROPIC SPINODAL DECOMPOSITION

We present a modification of the Cahn-Hilliard-Cook model to describe spinodal decomposition in an anisotropic fluid mixture, such as a blend of liquid crystals or a polymer solution under an extensional flow, and solve for the early time evolution of the structure function within a linear approximation. Spinodal decomposition is predicted to lead to the formation of a fibrillar or lamellar structure, depending on the symmetry of the system. This may account for the fibrillar morphology which has been observed in the phase separation of a liquid-crystal polymer solution. The results of a numerical simulation are presented to illustrate the type of structure predicted.