Applications of Nematic Liquid Crystals

By far the most important commercial applications of nematic liquid crystals are in the a multi-billion dollar display industry. Cholesteric, or chiral nematic liquid crystals have been used in coloured guest-host displays and in thermography/ther-mochromic applications. 

At present the applicability of nematic liquid crystals as anisotropic solvents in nmr spectroscopy seems to be limited to relatively simple and symmetric molecules which do not have more than 8 protons [40, 44]. Beyond this limit the spectra become prohibitively complicated and extensive overlapping of the lines occurs. Thus, a simple molecule as cyclohexane yields only a very broad spectrum [44]. 

Application of Nematic Liquid Crystals in Coherence Optics 153... 

Apart from high strength materials formed from nematic polymer fibres, most applications of nematic liquid crystals depend on their anisotropic optical properties. As a consequence the refractive indices of nematics are of prime importance in the development of materials for applications. The refractive indices are determined by the molecular polarisability coupled to the mientational order of the mesogens in the liquid crystal phase, so refractive indices can provide a direct probe of the order parameter. Furthermore the optical properties of liquid crystal films are frequently used to determine phase behaviour, identify phase types through characteristic optical textures or explore the properties of defects, and such experiments rely on the anisotropy in the refractive index of the material. The first tool of a liquid crystal scientist is the polarising microscope, which emphasises the importance of optical properties in general and refractive indices in particular to the stufy of liquid crystals. 

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