Dielectric studies of ferroelectric liquid crystals

Iwao Teraoka, Richard L. Siemens, Robert J. Twieg, Kathleen Betterton

Research output: Contribution to journalArticle

Abstract

The dielectric properties of some ferroelectric alpha-chloroester thiobenzoate liquid crystal materials have been studied using a Du Pont 2970 dielectric analyzer (DETA) in the 0.01 Hz-100 kHz range. These materials exhibit smectic A and chiral smectic C mesophases, as well as additional mesophases in some cases. Transitions involving the chiral smectic C phase are of most interest because this phase has ferroelectric properties. The effect on these transitions of fluorine addition to the alkoxy tail was investigated. The Goldstone mode and soft mode are seen in the frequency dispersion curves of the dielectric loss factor. Very low heating rates of 0.01°C min-1 and small step-wise increments are possible, providing measurements at small temperature increments which permit close observation of the transition regions. DSC measurements and optical microscopy observations were also performed and the three techniques were found to be complementary.

Original languageEnglish (US)
Pages (from-to)47-54
Number of pages8
JournalThermochimica Acta
Volume192
Issue numberC
DOIs
StatePublished - Dec 12 1991

Fingerprint

Liquid Crystals
Liquid crystals
Ferroelectric materials
liquid crystals
Fluorine
Dielectric losses
Heating rate
Dielectric properties
Optical microscopy
dielectric loss
fluorine
dielectric properties
analyzers
microscopy
heating
curves
Temperature
temperature
alkoxyl radical

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Physical and Theoretical Chemistry

Cite this

Dielectric studies of ferroelectric liquid crystals. / Teraoka, Iwao; Siemens, Richard L.; Twieg, Robert J.; Betterton, Kathleen.

In: Thermochimica Acta, Vol. 192, No. C, 12.12.1991, p. 47-54.

Research output: Contribution to journalArticle

Teraoka, Iwao ; Siemens, Richard L. ; Twieg, Robert J. ; Betterton, Kathleen. / Dielectric studies of ferroelectric liquid crystals. In: Thermochimica Acta. 1991 ; Vol. 192, No. C. pp. 47-54.
@article{83bb274f13ca4b5fac9fd275aebe6842,
title = "Dielectric studies of ferroelectric liquid crystals",
abstract = "The dielectric properties of some ferroelectric alpha-chloroester thiobenzoate liquid crystal materials have been studied using a Du Pont 2970 dielectric analyzer (DETA) in the 0.01 Hz-100 kHz range. These materials exhibit smectic A and chiral smectic C mesophases, as well as additional mesophases in some cases. Transitions involving the chiral smectic C phase are of most interest because this phase has ferroelectric properties. The effect on these transitions of fluorine addition to the alkoxy tail was investigated. The Goldstone mode and soft mode are seen in the frequency dispersion curves of the dielectric loss factor. Very low heating rates of 0.01°C min-1 and small step-wise increments are possible, providing measurements at small temperature increments which permit close observation of the transition regions. DSC measurements and optical microscopy observations were also performed and the three techniques were found to be complementary.",
author = "Iwao Teraoka and Siemens, {Richard L.} and Twieg, {Robert J.} and Kathleen Betterton",
year = "1991",
month = "12",
day = "12",
doi = "10.1016/0040-6031(91)87146-N",
language = "English (US)",
volume = "192",
pages = "47--54",
journal = "Thermochimica Acta",
issn = "0040-6031",
publisher = "Elsevier",
number = "C",

}

TY - JOUR

T1 - Dielectric studies of ferroelectric liquid crystals

AU - Teraoka, Iwao

AU - Siemens, Richard L.

AU - Twieg, Robert J.

AU - Betterton, Kathleen

PY - 1991/12/12

Y1 - 1991/12/12

N2 - The dielectric properties of some ferroelectric alpha-chloroester thiobenzoate liquid crystal materials have been studied using a Du Pont 2970 dielectric analyzer (DETA) in the 0.01 Hz-100 kHz range. These materials exhibit smectic A and chiral smectic C mesophases, as well as additional mesophases in some cases. Transitions involving the chiral smectic C phase are of most interest because this phase has ferroelectric properties. The effect on these transitions of fluorine addition to the alkoxy tail was investigated. The Goldstone mode and soft mode are seen in the frequency dispersion curves of the dielectric loss factor. Very low heating rates of 0.01°C min-1 and small step-wise increments are possible, providing measurements at small temperature increments which permit close observation of the transition regions. DSC measurements and optical microscopy observations were also performed and the three techniques were found to be complementary.

AB - The dielectric properties of some ferroelectric alpha-chloroester thiobenzoate liquid crystal materials have been studied using a Du Pont 2970 dielectric analyzer (DETA) in the 0.01 Hz-100 kHz range. These materials exhibit smectic A and chiral smectic C mesophases, as well as additional mesophases in some cases. Transitions involving the chiral smectic C phase are of most interest because this phase has ferroelectric properties. The effect on these transitions of fluorine addition to the alkoxy tail was investigated. The Goldstone mode and soft mode are seen in the frequency dispersion curves of the dielectric loss factor. Very low heating rates of 0.01°C min-1 and small step-wise increments are possible, providing measurements at small temperature increments which permit close observation of the transition regions. DSC measurements and optical microscopy observations were also performed and the three techniques were found to be complementary.

UR - http://www.scopus.com/inward/record.url?scp=44949272371&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=44949272371&partnerID=8YFLogxK

U2 - 10.1016/0040-6031(91)87146-N

DO - 10.1016/0040-6031(91)87146-N

M3 - Article

VL - 192

SP - 47

EP - 54

JO - Thermochimica Acta

JF - Thermochimica Acta

SN - 0040-6031

IS - C

ER -