An infrared study of phase-III poly(vinylidene fluoride)

Bachmann, Michael; Gordon, W. L.; Koenig, Jack L.; Lando, J. B.

doi:10.1063/1.325780

Cited by 206 publications

(126 citation statements)

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“…Infrared spectra were examined over a broad temperature range as an alternative means to elucidate the nature of the transition. In poly(vinylidiene fluoride), an -i absorption band near 510 cm has been assigned to a -CF 2 bending 11,12 mode within TTT segments of the chainl ; this band shifts to %530 cm -for the TGTG conformation' 1 2 The copolymer investigated -l here exhibits an absorption band at 506 cm that we initially considered characteristic of TTT segments; such attribution has also been made by Yamada et al 5 for a band observed at 310 cm 1 (pre--i sumably the same as our 506 cm band). However, as shown in Figure 7a, this band does not shift in wavenumber as the sample is…”

Section: Minimentioning

confidence: 99%

Structural and dielectric investigation on the nature of the transition in a copolymer of vinylidene fluoride and trifluoroethylene (52/48 mol %)

Davis¹,

Furukawa²,

Lovinger³

et al. 1982

Macromolecules

156

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Unclassified I54L DECL ASSI FICATION/ DOWN GRAOING SCHEDULE 16.Thidocunienthas beena pprovdV for public :olecnio and sale; its istruti s unlimited. 1S. SUPPLEMENTARY MOTES Submitted to Macromolecules KEY WORDS (ContInue on reverse ede It neceeemy end Identify by block number)Chain conformation; crystalline transformation; Curie temperature; dielectric anomaly; ferroelectric-paraelectric transition; intramolecular transformation; piezoelectricity; polytrifluoroethylene; pyroelectricity; thermal expansion; trifluoroethylene copolymer; vinylidene fluoride copolymer ZABSTRACT (Continue an reverse aide If necoesesv and Identify by block numnber)The effect of temperature on the structure and dielectric properties of a 52/ LLJ vestigated at temperatures up to 140 6C. Undrawn or unpoled specimens contain j an intimate mixture of two disordered crystalline phases, both of which under-LA.. Ri 125 011 -,t-14TY CLASSIFICATION OF THIS PAGE(han Date Entered)Block 20.to a single, well-ordered all-trans conformation, leading to remanent polarization with piezoelectric and pyroelectric coefficients comparable to those of poly(vinylidene fluoride). The changes in crystal phase and dipole orientation upon poling result in a reduction of the dielectric constant at room temperature a shift of the dielectric anomaly to -80 C, stability of the all-trans crystal phase to somewhat higher temperatures, and a discrete change in d-spacing to that of the disordered 3/1-helical conformation at the transition region. The loss of polarization in poled specimens at this ferroelectric-to-paraelectric transition is attributable primarily to the molecular change from the polar all-trans conformation to its non-polAr, disordered 3/1-helical counterpart, as well as to the onset of rotational dipolar motions leading to the die'ectric anomaly. The changes in crystal phase and dipole orientation upon poling result in a reduction of the dielectric constant at room temperature, a shift of the dielectric anomaly to -80 0 C, stability of the all-trans crystal phase to somewhat higher temperatures, and a discrete change in d-spacing to that of the disordered 3/1 helical conformation at the transition region. The loss of polarization in poled specimens at this ferroelectric-to-paraelectric transition is attributable primarily to the molecular change from the polar all-trans conformation to its non-polar, disordered 3/1-helical counterpart, as well as to the onset of rotational dipolar motions leading to the dielectric anomaly.

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Section: Minimentioning

confidence: 99%

Structural and dielectric investigation on the nature of the transition in a copolymer of vinylidene fluoride and trifluoroethylene (52/48 mol %)

Davis¹,

Furukawa²,

Lovinger³

et al. 1982

Macromolecules

156

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“…Figure 1 shows the FTIR spectra of PVDF blends with different weight fractions of SAN (PVDF/ SAN: a) 100/0; b) 90/10; c) 80/20; d) 70/30; e) 50/50; f) 20/80; g) 0/100) crystallized in DMF at 50°C. For PVDF, 3020 and 2980 cm -1 were attributed to the symmetrical and asymmetrical stretching vibration of CH 2 [16,24]. For SAN, two peaks at 2930 and 2850 cm -1 corresponded to the CH 2 vibration.…”

Section: Characterization Techniquesmentioning

confidence: 99%

“…Vibrational bands at around 530 cm -1 (CF 2 bending), 615 and 765 cm -1 (CF 2 bending and skeletal bending) and 795 cm -1 (CH 2 rocking) refer to α-phase. Vibrational bands at around 510 cm -1 (CF 2 bending) and 839 cm -1 (CH 2 rocking) correspond to β-phase [16,23]. Figure 1 shows the FTIR spectra of PVDF blends with different weight fractions of SAN (PVDF/ SAN: a) 100/0; b) 90/10; c) 80/20; d) 70/30; e) 50/50; f) 20/80; g) 0/100) crystallized in DMF at 50°C.…”

Section: Characterization Techniquesmentioning

confidence: 99%

“…The content of β-phase was characterized by the absorbance ratio A β of the FTIR absorption peaks at 839 cm -1 and peaks at 2980 cm -1 as Equation (1): (1) where A 839 represented the FTIR absorbance peak height at 839 cm -1 , characteristic of β-phase. The absorbance peak height at 2980 cm -1 (independent on the crystalline phase of PVDF [16] and SAN contents) was regarded as constant. DSC was conducted using a TA Instruments Q-200 (USA) under a dry nitrogen atmosphere.…”

Section: Characterization Techniquesmentioning

confidence: 99%

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Effect of solution-blended poly(styrene-co-acrylonitrile) copolymer on crystallization of poly(vinylidene fluoride)

Xia¹,

Zhao²,

Chen³

et al. 2010

Express Polym. Lett.

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“…[10,24] The 1113 cm -1 relatively intense peak in films deposited by continuous CVP process is assigned to the c-phase. [27] In pulsed deposited CPV films, the 1113 cm -1 peak is absent and other c-phase [28]…”

Section: Molecular Structure Of Filmsmentioning

confidence: 99%

Ferroelectric Poly(vinylidene fluoride) Thin Films Grown by Low‐Pressure Chemical Vapor Polymerization

Rastogi

Desu

2006

Chemical Vapor Deposition

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Ferroelectric poly(vinylidene fluoride) polymer (VDF 2 ) n thin-film formation by a low-pressure chemical vapor polymerization (CVP) process is described. The process involves polymerization of an isotropic vinylidene fluoride monomer condensate layer by cleavage of C double bonds using :CF 2 initiators derived from hot-filament, thermochemical decomposition of the hexafluoropropylene oxide C 3 F 6 O. Two different growth modes on the film surface and in the bulk are identified by Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) studies. Surface impingement of :CF 2 induces lateral growth of molecular chains in trans conformation. Due to the initiation of polymerization at random surface sites, amorphous b-phase growth is also observed. Bulk growth of polymer film involves chain formation dominated by gauche conformations having a predominance of the a-phase. Ferroelectric investigations of (VDF 2 ) n films show spontaneous polarization and hysteresis effects, which improves on crystallization. Typical polarization values of 3.5 and 1.5 lC cm -2 in the planar and normal directions, respectively, are observed after crystallization. Structural defects in the molecular chains give rise to space charge conduction which affects polarization switching properties. The low-pressure CVP technique is compatible with sub-micrometer semiconductor device fabrication and also provides a novel method for incorporating additional functional units into the molecular chains to control the film properties.

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An infrared study of phase-III poly(vinylidene fluoride)

Cited by 206 publications

References 10 publications

Structural and dielectric investigation on the nature of the transition in a copolymer of vinylidene fluoride and trifluoroethylene (52/48 mol %)

Structural and dielectric investigation on the nature of the transition in a copolymer of vinylidene fluoride and trifluoroethylene (52/48 mol %)

Effect of solution-blended poly(styrene-co-acrylonitrile) copolymer on crystallization of poly(vinylidene fluoride)

Ferroelectric Poly(vinylidene fluoride) Thin Films Grown by Low‐Pressure Chemical Vapor Polymerization

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