DEPENDENCE OF THE ROTATIONAL VISCOSITY OF NEMATIC MIXTURES ON THE ROTATIONAL DIFFUSION CONSTANTS OF THEIR COMPONENTS

The relation between the rotational viscosity gamma1 of binary nematic mixtures and the different rotational diffusion constants D(ri) of th eir components was studied by a combination of director reorientation experiments with dielectric relaxation spectroscopy. Marrucci's theory for the viscosity of single component nematics can be applied when th e weighted reciprocal rotational diffusion constants are averaged arit hmetically. An explanation is given by considering the sum of the mole cular frictional torques.