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

Journal Article · Tue Dec 15 00:00:00 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), Vol. 46:12; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

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