FLOW-ALIGNMENT AND VISCOSITY RULES FOR SINGLE-PHASE BINARY MESOMORPHIC MIXTURES

A macroscopic model for incompressible homogeneous (single phase) bina ry nematic mixtures, under isothermal conditions is given. The rheolog ical model is a generalization of the standard Ericksen's nematorheolo gical model for single component uniaxial rod-like nematic liquid crys tals. Its special cases include single component orthorhombic biaxial nematics and single component uniaxial nematics. The theory is used to formulate rules for the rotational viscosity and the reactive paramet er of nematic mixtures in the presence of weak flows. The predicted mi xture rules for the reactive parameter and rotational viscosity are an alysed as a function of concentration and rotational viscosity ratio f or various monomeric and polymeric mixtures, and for rod-rod, disc-dis c, and rod-disc nematic mixtures. The mixture rules are used to comput e alignment phase diagrams and alignment transition (orientational ins tability) thresholds.