Uniaxial-to-biaxial cholesteric and nematic phase transitions on a lyotropic alcohol-free mixture

Journal Article · Tue Dec 15 04:00:00 EST 1992 · Physical Review A. General Physics; (United States)

DOI:https://doi.org/10.1103/PhysRevA.46.7630· OSTI ID:7156498

de Sant'Ana, Z A; Figueiredo Neto, A M ^[1]

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1. Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 20516, 01498-970 Sao Paulo, Sao Paulo (Brazil)

Interferometric measurements of the chirality-induced biaxiality in the vicinity of the uniaxial-to-biaxial cholesteric transition of the lyotropic system potassium laurate, decylammonium chloride, H[sub 2]O, and brucine sulfate are reported. The mean-field approach to describe the cholesteric-to-cholesteric transition allows an estimate of the ratio between coefficients of the Landau expansion. The values of the bare correlation length, [xi][sub 0][similar to]1000 A, calculated are larger than in lyotropic systems with alcohol. The chirality-induced biaxiality measurements in the limit of zero elastic field ([ital q][sup 2]=0) and the birefringence measurements in the nematic phase confirm critical properties of the uniaxial-to-biaxial nematic transition. The critical exponents for the order parameter ([beta]) and the susceptibility ([gamma]) are in good agreement with the values calculated for the [ital XY] model.

• OSTI ID: 7156498
• Journal Information: Physical Review A. General Physics; (United States), Journal Name: Physical Review A. General Physics; (United States) Vol. 46:12; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602 -- Other Materials-- Structure & Phase Studies
665000* -- Physics of Condensed Matter-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALI METAL COMPOUNDS
ALKALOIDS
AMMONIUM CHLORIDES
AMMONIUM COMPOUNDS
AMMONIUM HALIDES
CHLORIDES
CHLORINE COMPOUNDS
CRYSTAL-PHASE TRANSFORMATIONS
CRYSTALS
DISPERSIONS
ENERGY
FLUIDS
FREE ENERGY
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
LIQUID CRYSTALS
LIQUIDS
MEAN-FIELD THEORY
MIXTURES
ORDER PARAMETERS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POTASSIUM COMPOUNDS
THERMODYNAMIC PROPERTIES
WATER