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X-Ray Studies of Tilted Hexatic Phases in Thin Liquid-Crystal Films
(American Physical Society, 1985)
X-ray-diffraction studies of the structures and phase transitions of the tilted hexatic phases (smectic F and smectic I) in thin liquid-crystal films of 4-n-heptyloxybenzylidene-4-n-heptylaniline (70.7) are reported. The ...
Synchrotron X-Ray Study of the Thickness Dependence of the Phase Diagram of Thin Liquid-Crystal Films
(American Physical Society, 1984)
The phase diagram of freely suspended thin films of heptyloxybenzylidene-heptylaniline shows dramatic changes for thicknesses below 22 layers. The most surprising feature of the phase diagram is the inclusion of two phases ...
X-Ray Scattering Study of the \(Smectic-A_1\) to \(Smectic-A_2\) Transition
(American Physical Society, 1985)
X-ray scattering measurements are reported for critical \(smectic-A_2\) fluctuations along a line of second-order transitions between the \(smectic-A_1\) and \(smectic-A_2\) phases in mixtures of hexylphenyl cyanobenzoyloxy ...
Integrated X-Ray-Scattering Intensity Measurement of the Order Parameter at the Nematic-to-Smectic-A Phase Transition
(American Physical Society, 1985)
The temperature dependence of the square of the smectic order parameter, \(\mid \psi \mid^2\), was determined from the integrated x-ray scattering intensity. The data are described very well by the form \(I(t)/I(0)=1 \mp ...
Absolute Measurement of the Critical Behavior of the Smectic Elastic Constant of Bilayer and Monolayer Smectic-A Liquid Crystals on Approaching the Transition to the Nematic Phase
(American Physical Society, 1984)
A new technique which provides an absolute measurement of the smectic elastic constant B is presented. This technique measures second sound on samples whose top surface is an air—liquid-crystal interface. The free surface ...
Absolute Measurement of the Critical Properties of Second Sound at the Smectic-A-to-Nematic Phase Transition in 8OCB
(American Physical Society, 1981)
Light scattered from the driven free surface of the smectic-A phase of octyloxy cyanobiphenyl (8OCB) provides a low-frequency measurement of second sound. This yields an absolute measurement of the smectic elastic constant, ...
Synchrotron Studies of the First-Order Melting Transitions of Hexatic Monolayers and Multilayers in Freely Suspended Liquid-Crystal Films
(American Physical Society, 1989)
Synchrotron x-ray diffraction has been used to study the surface and the interior hexatic-to-liquid (smectic-I to smectic-C) melting transitions of freely suspended liquid-crystal films of N-[4'-(n-heptyl)benzylidene]-4- ...
X-Ray and Optical Studies of the Thickness Dependence of the Phase Diagram of Liquid-Crystal Films
(American Physical Society, 1987)
A comprehensive study of the thickness dependence of the phase diagram of freely suspended films of the liquid crystal 4-n-heptyloxybenzylidene-4-n-heptylaniline (7O.7) between \(50 and 69^{\circ}C\) is reported. In thick ...
Synchrotron X-Ray Observation of Surface Smectic-I Hexatic Layers on Smectic-C Liquid-Crystal Films
(American Physical Society, 1987)
Synchrotron x-ray diffraction methods employing a position-sensitive detector were used to study smectic-C (SmC) and smectic-I (SmI) phases in thin (2–6 molecular layers) liquid-crystal films of 4-(n-heptyloxy)benzyliden ...
Dislocation Model for Restacking Phase Transitions in Crystalline-B Liquid Crystals
(American Physical Society, 1984)
A dislocation-mediated model is presented for restacking phase transitions that have been observed in a variety of lamellar (liquid crystalline) systems. The model explains the existence of nonhexagonal crystalline (smectic)-B ...