Micellar shape anisotropy on lyotropic nematic phases

In this work we show, that with the introduction of the micellar shape anisotropy in the order parameter of a lyotropic liquid crystal, it is possible to understand, in a unified way, the features observed in the phase diagram of these materials. Using the de Gennes connection between microscopic and macroscopic order parameters, such an extended order parameter is constructed from a geometrical conception of the micelles. Our theoretical results will be correlated with refractive index experimental data near the uniaxial-biaxial nematic phase transitions of a lyotropic mixture of potassium laurate, decanol and deuterium oxide.