Nematic phases and their properties

Lyotropic nematic phases have been discovered a long time after the finding of the lyotropic mesophases. In 1967 first evidence of such a phase was published [87] but it took more than 10 years to prove unambiguously the existence of these phases [88]. The first nematic 

The identification of the Nc and Nd phases can be archived by polarization microscopy based on their different textures which are presented in Fig. 11.28 a and 11.28 b. H-NMR spectroscopic studies and orientation experiments on the nematic phases in a magnetic field are suitable for their detection, especially if SANS measurements are done on oriented samples. For these experiments the phases have to be prepared with D2O instead of H2O. This 

Finally it shall be mentioned that until now no inverse nematic phases could be detected. Also the existence of nematic phases in non-polar solvents could not be proven for any studied system. Thus it is not yet possible to replace the thermotropic nematic phases in displays by lyotropic systems because lyotropic nematics caimot be orientated in an electric field with low voltages due to the rather high conductivity of the water solvent compared to non-polar organic compounds. 

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