Effect of the anionic azo dye sunset yellow in lyotropic mixtures with uniaxial and biaxial nematic phases

The effects of the anionic azo dye Sunset Yellow on the stabilization of lyotropic uniaxial and biaxial nematic phases and on the uniaxial to biaxial phase transitions were studied. The dye was added in different concentrations to the host ternary mixture of cationic surfactant dodecyltrimethylammonium bromide, 1-dodecanol, and water. Furthermore, an investigation examined the role of the dye in the lyotropic host mixture in comparison to some inorganic salts containing anions of the Hofmeister series.