Vibrational spectroscopic study on ferroelectric phase transition of vinylidene fluoride-trifluoroethylene copolymers: 2. Temperature dependences of the far-infrared absorption spectra and ultrasonic velocity

Kohji Tashiro, Yuzo Itoh, Shin Nishimura, Masamichi Kobayashi

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The temperature dependence of far infrared absorption spectra was measured for vinylidene fluoride-trifluoroethylene (VDF-TrFE) copolymers with various VDF contents. For 55, 72 and 82 mol% VDF samples, the trans-gauche conformational transition was detected clearly. Near the ferroelectric phase transition temperature of the 55 mol% VDF sample, the band at 116 cm-1, the skeletal torsional mode of the trans zig-zag conformation, was observed to transfer continuously to the position of the torsional band of the gauche type skeletal conformation at 108 cm-1, suggesting a softening behaviour of the skeletal vibrational mode in the structural transition region. The ultrasonic modulus was found to exhibit an unusual minimum in the same temperature region. This anomalous behaviour was interpreted in terms of the coupling between the optical phonon of the skeletal torsional mode and the acoustic phonon through the piezoelectric and electrostrictive effects.

Original languageEnglish
Pages (from-to)1017-1026
Number of pages10
Journalpolymer
Volume32
Issue number6
DOIs
Publication statusPublished - Jan 1 1991
Externally publishedYes

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Ultrasonic velocity
Infrared absorption
Ferroelectric materials
Conformations
Absorption spectra
Copolymers
Phase transitions
Superconducting transition temperature
Ultrasonics
Acoustics
Temperature
vinylidene fluoride-trifluoroethylene copolymer

All Science Journal Classification (ASJC) codes

  • Polymers and Plastics
  • Organic Chemistry

Cite this

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title = "Vibrational spectroscopic study on ferroelectric phase transition of vinylidene fluoride-trifluoroethylene copolymers: 2. Temperature dependences of the far-infrared absorption spectra and ultrasonic velocity",
abstract = "The temperature dependence of far infrared absorption spectra was measured for vinylidene fluoride-trifluoroethylene (VDF-TrFE) copolymers with various VDF contents. For 55, 72 and 82 mol{\%} VDF samples, the trans-gauche conformational transition was detected clearly. Near the ferroelectric phase transition temperature of the 55 mol{\%} VDF sample, the band at 116 cm-1, the skeletal torsional mode of the trans zig-zag conformation, was observed to transfer continuously to the position of the torsional band of the gauche type skeletal conformation at 108 cm-1, suggesting a softening behaviour of the skeletal vibrational mode in the structural transition region. The ultrasonic modulus was found to exhibit an unusual minimum in the same temperature region. This anomalous behaviour was interpreted in terms of the coupling between the optical phonon of the skeletal torsional mode and the acoustic phonon through the piezoelectric and electrostrictive effects.",
author = "Kohji Tashiro and Yuzo Itoh and Shin Nishimura and Masamichi Kobayashi",
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T1 - Vibrational spectroscopic study on ferroelectric phase transition of vinylidene fluoride-trifluoroethylene copolymers

T2 - 2. Temperature dependences of the far-infrared absorption spectra and ultrasonic velocity

AU - Tashiro, Kohji

AU - Itoh, Yuzo

AU - Nishimura, Shin

AU - Kobayashi, Masamichi

PY - 1991/1/1

Y1 - 1991/1/1

N2 - The temperature dependence of far infrared absorption spectra was measured for vinylidene fluoride-trifluoroethylene (VDF-TrFE) copolymers with various VDF contents. For 55, 72 and 82 mol% VDF samples, the trans-gauche conformational transition was detected clearly. Near the ferroelectric phase transition temperature of the 55 mol% VDF sample, the band at 116 cm-1, the skeletal torsional mode of the trans zig-zag conformation, was observed to transfer continuously to the position of the torsional band of the gauche type skeletal conformation at 108 cm-1, suggesting a softening behaviour of the skeletal vibrational mode in the structural transition region. The ultrasonic modulus was found to exhibit an unusual minimum in the same temperature region. This anomalous behaviour was interpreted in terms of the coupling between the optical phonon of the skeletal torsional mode and the acoustic phonon through the piezoelectric and electrostrictive effects.

AB - The temperature dependence of far infrared absorption spectra was measured for vinylidene fluoride-trifluoroethylene (VDF-TrFE) copolymers with various VDF contents. For 55, 72 and 82 mol% VDF samples, the trans-gauche conformational transition was detected clearly. Near the ferroelectric phase transition temperature of the 55 mol% VDF sample, the band at 116 cm-1, the skeletal torsional mode of the trans zig-zag conformation, was observed to transfer continuously to the position of the torsional band of the gauche type skeletal conformation at 108 cm-1, suggesting a softening behaviour of the skeletal vibrational mode in the structural transition region. The ultrasonic modulus was found to exhibit an unusual minimum in the same temperature region. This anomalous behaviour was interpreted in terms of the coupling between the optical phonon of the skeletal torsional mode and the acoustic phonon through the piezoelectric and electrostrictive effects.

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