A soft matter random-field system: the nematic to smectic-A transition in an 8OCB-aerosil dispersion
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چکیده
منابع مشابه
Random-field effects on the nematic–smectic-A phase transition due to silica aerosil particles
A high-resolution calorimetric study has been made on the smectic-A to nematic phase transition in liquid crystals perturbed by the dispersion of 70-Å-diam silica spheres ~aerosils!. The specific heat peak of this transition decreases in amplitude and shifts to lower temperatures with increasing silica density. However, it remains sharp in comparison to the effects of aerogel confinement at the...
متن کاملEffect of a quenched random field on a continuous symmetry breaking transition: nematic to smectic-A transition in octyloxycyanobiphenyl-aerosil dispersions.
High-resolution x-ray diffraction and ac-calorimetric experiments have been carried out on the liquid-crystal octyloxycyanobiphenyl in which aerosil particles are dispersed. The measurements were made over a temperature range around the bulk nematic to smectic-A transition temperature. At this transition the liquid crystal breaks translational symmetry in a single direction. The silica particle...
متن کاملHigh-resolution calorimetric study of the nematic to smectic-A transition in aligned liquid crystal-aerosil gels.
High-resolution ac calorimetry has been used to study the nematic to smectic- A (N-SmA) phase transition in the liquid crystal octylcyanobiphenyl (8CB) confined in aligned colloidal aerosil gels. A stable and robust nematic alignment was achieved by repeated thermal cycling of the samples in the presence of a strong uniform magnetic field. In some ways (such as transition temperature and integr...
متن کاملHigh-resolution x-ray study of nematic-smectic-A and smectic-A-reentrant-nematic transitions in liquid-crystal-aerosil gels.
We have studied the effects of quenched random disorder created by dispersed aerosil nanoparticle gels on the nematic to smectic- A (N- SmA ) and smectic- A to reentrant nematic ( SmA -RN) phase transitions of thermotropic liquid-crystal mixtures of hexyloxycyanobiphenyl (6OCB) and octyloxycyanobiphenyl (8OCB). These effects are probed using high-resolution synchrotron x-ray diffraction techniq...
متن کاملCritical behavior at the smectic-A to nematic transition confined to a random network.
The smectic-A to nematic ~Sm-A–N! transition was studied confined to the randomly interconnected voids of Millipore filters via a high resolution calorimetry. The heat capacity peaks evolve from sharp and prominent to broad and small depending on void size. The random confinement drives the heat capacity critical exponent from the bulk value towards zero, indicating a confinement-induced decoup...
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ژورنال
عنوان ژورنال: Acta Crystallographica Section A Foundations of Crystallography
سال: 2002
ISSN: 0108-7673
DOI: 10.1107/s0108767302087548