Determination of order parameter and birefringence depending on temperature of nematic calamitic mesophase formed by TTAB + water binary system using polarized microscopy

In the present study, the temperature-dependent optical transmittances of lyotropic nematic calamitic mesophase formed by TTAB-water binary system were measured for certain wavelengths under polarized microscopy to obtain macroscopic order parameter with birefringence. Because birefringence in lyotropics is quite small (order of 10-3), it is very difficult to make sensitive measurements of birefringence and to obtain order parameter. The study easily achieved the order parameter depending on temperature for different wavelengths only using polarized microscopy. Therefore, the parameter could be more easily determined in liquid crystal application and the physical properties of liquid crystals, especially for lyotropics, can be better understood.