Anomalous hydrodynamic behaviors of smectic liquid crystals at low frequencies

• Published in: Japanese Journal of Applied Physics Vol. 30; no. 4; pp. 754 - 763
• Main Authors: YAMAMOTO, J, OKANO, K
• Format: Journal Article
• Language: English
• Published: Tokyo Japanese journal of applied physics 01.04.1991
• Subjects: Condensed matter: structure, mechanical and thermal properties; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Other topics in equations of state, phase equilibria, and phase transitions; Physics; Viscosity; Temperature; Smectic smectic transformation; Hydrodynamics; Chiral compound; Critical exponent; Smectic state; Experimental study; Liquid crystals; Phase transformation; Benzenic compound; Frequency; Anomaly; Magnetic field; Power law; Bulk modulus; Organic compounds
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/jjap.30.754

We report the details of the measurements of the layer compression modulus B and the longitudinal viscosity \tildeη of several thermotropic smectic phases in the frequency range from 10 Hz to 1 kHz. We confirmed for smectic phases having liquidlike layers (including smectic-A, smectic-C and chiral smectic-C phases) that \tildeη has an anomalous frequency (ω) dependence of the type \tildeκ/ω predicted theoretically by Mazenko, Ramaswamy and Toner, and also by Katz and Lebedev. The temperature dependence of B and the strength of the anomalous viscosity \tildeκ were measured in detail, which revealed, in particular, that a close correlation exists between \tildeκ and B . We also found that, under an applied magnetic field, which tends to suppress the thermal fluctuations of smectic layers, \tildeκ decreases whereas B increases, a result which is consistent with the premise of the advocated theories.