Oscar R. Santos, Wladimir S. Braga, Danilo D. Luders, Newller M. Kimura, Manuel Simões e Antonio J. Palangana

Journal of Molecular Liquids – Volume: 197; Pages: 120–123; DOI: 10.1016/j.molliq.2014.05.005

The calamitic nematic (NC)–biaxial nematic (NB)–discotic nematic (ND) phase transitions are studied in a potassium laurate-decanol-potassium sulfate and water mixture by optical conoscopy. The NC−(ND+) phase is uniaxially negative (positive) as expected. A biaxial negative (NB−) nematic phase is optically characterized and confirmed through conoscopic image, inside the biaxial range, beyond the known biaxial positive (NB+) nematic phase. Conoscopic image of a biaxial nematic induced by material flow from ND+ phase is investigated and discussed in this work.