Nematic Mixtures for Liquid Crystal Light Modulators

In the last few years, the following Multicomponent Nematic Liquid Crystalline (MNLC) mixtures of medium and high optical anisotropy Δn have been developed in Military University of Technology (MUT) in Warsaw:

• W1898 (composed mainly of two and three alkylcyclohexylbenzene and alkylbicyclo-hexylbenzene isothiocyanates),

• W1820 (composed mainly of fluoro-substituted alkylbiphenylisothiocyanates),

• W1852 (composed mainly of fluoro-substituted isothiocyanates, alkylbiphenyls, alkylcyclo-hexylbiphenyls and alkylbicycloheksylobiphenyls),

• W1825 and W1791 (composed mainly of fluoro-substituted isothiocyanates, alkyltolanes and alkylphenyltolanes),

• W1865 (composed mainly of fluoro-substituted isothiocyanates, alkylphenyls and alkylbiphenyltolanes),

• W1115 (composed mainly of cyclohexanolcyanobenzenes, fluorobenzenes and hydrocarbons),

• W1795B (composed mainly of fluoro-terphenyls).

In this chapter, the material characteristics of the perpendicular and parallel εII(T) components of the permittivity tensors ε (T) at the frequency range of f є [10 Hz, 10 MHz]; bulk viscosity Γ(T); rotational viscosity γ(T), splay K11(T), twist K22(T), bend K33(T) and KTN(T) for transition from twisted to the nontwisted structure; ordinary no(λ) and extraordinary ne(λ) refractive indices for wavelength λ є [0.3μm, 1.6 μm] are described and discussed in the terms of applicability of MNLCs to Liquid Crystal electro-optical Devices (LCEOD).

Keywords: Birefringence fringes, Bulk viscosity, Homogeneous, Homeotropic and twisted alignment, Liquid crystal cell, Light modulators for naval, Negative nematic liquid crystals, Optical anisotropy, Positive nematic liquid crystals, Refractive indices, Rotational viscosity, Splay, Switching times, Twist.