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Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Critical linear thermal expansion in the smectic-A phase near the nematic-smectic phase transition
E Anesta1, G S Iannacchione, C W Garland
1Department of Physics, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA.
Abstract:
Recent high-resolution x-ray investigations of the smectic- A (SmA) phase near the nematic-to-SmA transition provide information about the critical behavior of the linear thermal expansion coefficient alpha// parallel to the director. Combining such data with available volume thermal expansion alpha(V) data yields the in-plane linear expansion coefficient alpha(perpendicular) . The critical behaviors of alpha// and alpha(perpendicular) are the same as those for alpha(V) and the heat capacity Cp. However, for any given liquid crystal, alpha//(crit) and alpha(perpendicular)(crit) differ in sign. Furthermore, the quantity alpha// (crit) is positive for SmAd partial bilayer smectics, while it is negative for nonpolar SmAm monomeric smectics. This feature is discussed in terms of the molecular structural aspects of these smectic phases.
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