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Synchrotron X-Ray Radiation (CHESS) Study of Electric-Field Induced Changes in the Structure of Thermotropic Side-Chain Liquid Crystals

Published online by Cambridge University Press:  15 February 2011

T. J. Bunning ,
S. G. McNamee ,
C. M. McHugh ,
S. S. Patnaik ,
C. K. Ober  and
W. W. Adams
T. J. Bunning
Affiliation:
WL/MLPJ, Wright-Patterson AFB, OH 45433
S. G. McNamee
Affiliation:
Dept. of MS&E, Cornell University, Ithaca, NY 14853
C. M. McHugh
Affiliation:
WL/MLPJ, Wright-Patterson AFB, OH 45433
S. S. Patnaik
Affiliation:
WL/MLPJ, Wright-Patterson AFB, OH 45433
C. K. Ober
Affiliation:
Dept. of MS&E, Cornell University, Ithaca, NY 14853
W. W. Adams
Affiliation:
WL/MLPJ, Wright-Patterson AFB, OH 45433
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Abstract

Synchrotron radiation from the Cornell High Energy Synchrotron Source (CHESS) was used to probe the alignment kinetics of a class of thermotropic siloxane-based liquid crystals under the influence of an electric field. The high flux allows for real-time investigation of microstructural changes as a function of frequency and temperature. The packing behavior of a pentamethylcyclosiloxane ring with pendant biphenyl mesogens was thoroughly investigated. The director orientation parameter, Sd, typically increased with decreasing temperature and was not strongly affected by frequency. Electric-field induced changes in the director orientation were also monitored. Upon application of an electric field, the nematic system exhibited a tendency to pack in columns with short-range correlation of the mesogens. Column correlation lengths are examined as a function of temperature for two frequencies. At the low temperature end of the mesophase, a tendency for the mesogens to layer pack was observed.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 307: Symposium L – Applications of Synchrotron Radiation Techniques to Materials Science , 1993 , 311
Copyright
Copyright © Materials Research Society 1993

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References

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