Universal law for the rotational viscosity of nematic liquid crystals

The rotational viscosity γ₁(T) of a nematic is of dominant importance for wide operating temperature display applications. In this paper we show that γ₁(T) is, except for a small prefactor variation, a universal function of T-Tg where Tg is the glass transition temperature. In a mixture Tg is a linear function of the component mole fractions and Tg of a component can be predicted from molecular structure by a simple phenomenological model. γ₁(T) of a mixture can thus be predicted from the molecular structures and concentrations of the components.