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Title: Temperature and Depth Dependence of Order in Liquid Crystal Interfaces

Abstract

We have studied the depth dependence and temperature behavior of the ordering of smectic-A films close to the smectic A-nematic transition, deposited on grated glass. X-ray grazing incidence geometry in reflection mode through the glass substrate was used to characterize the samples. Our results indicate the presence of a structure similar to the helical twist grain boundary phase. The structure has two maxima, one close to the glass-liquid crystal interface and another about 8 {mu}m above the surface. The structure at 8 {mu}m is the one that dominates at higher temperatures. In addition, we find that order is preserved to temperatures close to the nematic-isotropic transition temperature for the deeper gratings. We find also a dependence of the orientation of the structure with the depth of the grating and the elastic constant of the liquid crystal.

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930570
Report Number(s):
BNL-80750-2008-JA
Journal ID: ISSN 0021-8979; JAPIAU; TRN: US200904%%595
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 99; Journal Issue: 11
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; LIQUID CRYSTALS; INTERFACES; TEMPERATURE DEPENDENCE; ORDER PARAMETERS; PHASE TRANSFORMATIONS; MORPHOLOGY; national synchrotron light source

Citation Formats

Martinez-Miranda,L., and Hu, Y. Temperature and Depth Dependence of Order in Liquid Crystal Interfaces. United States: N. p., 2006. Web. doi:10.1063/1.2201750.
Martinez-Miranda,L., & Hu, Y. Temperature and Depth Dependence of Order in Liquid Crystal Interfaces. United States. doi:10.1063/1.2201750.
Martinez-Miranda,L., and Hu, Y. Sun . "Temperature and Depth Dependence of Order in Liquid Crystal Interfaces". United States. doi:10.1063/1.2201750.
@article{osti_930570,
title = {Temperature and Depth Dependence of Order in Liquid Crystal Interfaces},
author = {Martinez-Miranda,L. and Hu, Y.},
abstractNote = {We have studied the depth dependence and temperature behavior of the ordering of smectic-A films close to the smectic A-nematic transition, deposited on grated glass. X-ray grazing incidence geometry in reflection mode through the glass substrate was used to characterize the samples. Our results indicate the presence of a structure similar to the helical twist grain boundary phase. The structure has two maxima, one close to the glass-liquid crystal interface and another about 8 {mu}m above the surface. The structure at 8 {mu}m is the one that dominates at higher temperatures. In addition, we find that order is preserved to temperatures close to the nematic-isotropic transition temperature for the deeper gratings. We find also a dependence of the orientation of the structure with the depth of the grating and the elastic constant of the liquid crystal.},
doi = {10.1063/1.2201750},
journal = {Journal of Applied Physics},
number = 11,
volume = 99,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}