title: Orientational Order of a Lyotropic Chromonic Liquid Crystal Measured by Polarized Raman Spectroscopy.
abstract: Lyotropic chromonic liquid crystals are distinct from thermotropic nematics from a fundamental standpoint as the structure of the aggregating columns is a function of both the temperature and concentration. We report on the thermal evolution of orientational order parameters, both the second (=scalar) (⟨P200⟩ (=S)) and fourth (⟨P400⟩) order, of sunset yellow FCF aqueous solutions, measured using polarized Raman spectroscopy for different concentrations. The order parameter increases with the concentration, and their values are high in comparison with those of thermotropic liquid crystals. On the basis of Raman spectroscopy, we provide the strongest evidence yet that the hydrozone tautomer of SSY is the predominant form in aqueous solutions in the isotropic, nematic, and columnar phases, as well as what we believe to be the first measurements of (⟨P400⟩) for this system.
authors.affiliation: School of Materials Science and Engineering, ‡School of Chemistry and Biochemistry, and §Center for Advanced Research on Optical Microscopy, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Xuxia
authors.initials: X
authors.lastname: Yao
authors.affiliation: School of Materials Science and Engineering, ‡School of Chemistry and Biochemistry, and §Center for Advanced Research on Optical Microscopy, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Karthik
authors.initials: K
authors.lastname: Nayani
authors.affiliation: School of Materials Science and Engineering, ‡School of Chemistry and Biochemistry, and §Center for Advanced Research on Optical Microscopy, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Jung Ok
authors.initials: JO
authors.lastname: Park
authors.affiliation: School of Materials Science and Engineering, ‡School of Chemistry and Biochemistry, and §Center for Advanced Research on Optical Microscopy, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Mohan
authors.initials: M
authors.lastname: Srinivasarao