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Title: Pretransitional effects near the smectic-A-smectic-C* phase transition of hydrophilic and hydrophobic aerosil networks dispersed in ferroelectric liquid crystals

Abstract

A detailed x-ray scattering and high-resolution ac calorimetric study has been carried out near the smectic-A to chiral smectic-C phase transition of liquid-crystal compounds 4-(2-methyl butyl) phenyl 4-n-octylbiphenyl-4-carboxylate (CE8) and p-(n-decyloxy) benzylidene-p-amino-(2-methylbutyl) cinnamate (DOBAMBC) confined in hydrophilic and hydrophobic aerosil nanoparticle networks. The character of the transition, which is mean field near a tricritical point in bulk, is changed dramatically with an increase of aerosil-induced disorder. X-ray measurements revealed pretransitional behavior and compression of the smectic layers, phenomena that are strongly pronounced in high aerosil concentrations. A theoretical model that takes into account the interplay of relevant mechanisms is proposed to explain the observed phenomena. The effect of chirality on the interaction of liquid crystals with aerosils is discussed.

Authors:
 [1];  [2];  [3];  [2];  [1];  [4];  [5];  [2]
  1. National Centre for Scientific Research 'Demokritos', 153 10 Aghia Paraskevi (Greece)
  2. (Slovenia)
  3. Laboratory of Physics of Complex Systems, Faculty of Education, University of Maribor, Koroska 160, 2000 Maribor (Slovenia)
  4. Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana (Slovenia)
  5. Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia)
Publication Date:
OSTI Identifier:
21072378
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics; Journal Volume: 75; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevE.75.021702; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CALORIMETRY; CHIRALITY; COMPRESSION; FERROELECTRIC MATERIALS; LAYERS; LIQUID CRYSTALS; MEAN-FIELD THEORY; ORGANIC COMPOUNDS; PHASE TRANSFORMATIONS; X RADIATION; X-RAY DIFFRACTION

Citation Formats

Cordoyiannis, George, Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana, Kralj, Samo, Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana, Nounesis, George, Kutnjak, Zdravko, Zumer, Slobodan, and Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana. Pretransitional effects near the smectic-A-smectic-C* phase transition of hydrophilic and hydrophobic aerosil networks dispersed in ferroelectric liquid crystals. United States: N. p., 2007. Web. doi:10.1103/PHYSREVE.75.021702.
Cordoyiannis, George, Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana, Kralj, Samo, Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana, Nounesis, George, Kutnjak, Zdravko, Zumer, Slobodan, & Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana. Pretransitional effects near the smectic-A-smectic-C* phase transition of hydrophilic and hydrophobic aerosil networks dispersed in ferroelectric liquid crystals. United States. doi:10.1103/PHYSREVE.75.021702.
Cordoyiannis, George, Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana, Kralj, Samo, Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana, Nounesis, George, Kutnjak, Zdravko, Zumer, Slobodan, and Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana. Thu . "Pretransitional effects near the smectic-A-smectic-C* phase transition of hydrophilic and hydrophobic aerosil networks dispersed in ferroelectric liquid crystals". United States. doi:10.1103/PHYSREVE.75.021702.
@article{osti_21072378,
title = {Pretransitional effects near the smectic-A-smectic-C* phase transition of hydrophilic and hydrophobic aerosil networks dispersed in ferroelectric liquid crystals},
author = {Cordoyiannis, George and Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana and Kralj, Samo and Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana and Nounesis, George and Kutnjak, Zdravko and Zumer, Slobodan and Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana},
abstractNote = {A detailed x-ray scattering and high-resolution ac calorimetric study has been carried out near the smectic-A to chiral smectic-C phase transition of liquid-crystal compounds 4-(2-methyl butyl) phenyl 4-n-octylbiphenyl-4-carboxylate (CE8) and p-(n-decyloxy) benzylidene-p-amino-(2-methylbutyl) cinnamate (DOBAMBC) confined in hydrophilic and hydrophobic aerosil nanoparticle networks. The character of the transition, which is mean field near a tricritical point in bulk, is changed dramatically with an increase of aerosil-induced disorder. X-ray measurements revealed pretransitional behavior and compression of the smectic layers, phenomena that are strongly pronounced in high aerosil concentrations. A theoretical model that takes into account the interplay of relevant mechanisms is proposed to explain the observed phenomena. The effect of chirality on the interaction of liquid crystals with aerosils is discussed.},
doi = {10.1103/PHYSREVE.75.021702},
journal = {Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics},
number = 2,
volume = 75,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}