The polymorphism of poly(vinylidene fluoride). I. The effect of head-to-head structure

Lando, J. B.; Doll, W. W.

doi:10.1080/00222346808212449

Cited by 277 publications

(92 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many attempts have been made to prepare /~-form PVF2 by various methods which include growth from solution [1], mechanical deformation [2-5], crystallization at elevated pressures [6][7][8], application of a strong electric field [9][10][11] and the copolymerization with other fluorocarbons (i.e. trifluoro-or tetrafluoroethylene) [12,13]. Generally, in the sample of PVF 2 cooled from the melt, the e phase is predominant and transition to the /3 form has to be performed by stretching.…”

mentioning

confidence: 99%

β-phase formation of poly(vinylidene fluoride) from the melt induced by quenching

1987

View full text Add to dashboard Cite

Poly(vinylidene fluoride) (PVF2) exhibits at least four crystalline forms, c~, fl, 7 and 6, among which the/~ phase is the most important because of its extensive applications in piezoelectric and pyroelectric properties. Many attempts have been made to prepare /~-form PVF2 by various methods which include growth from solution [1], mechanical deformation [2-5], crystallization at elevated pressures [6][7][8], application of a strong electric field [9][10][11] and the copolymerization with other fluorocarbons (i.e. trifluoro-or tetrafluoroethylene) [12,13]. Generally, in the sample of PVF 2 cooled from the melt, the e phase is predominant and transition to the /3 form has to be performed by stretching. It would be very important if it were possible to prepare directly the fl phase from the melt. The only reported/~ crystallization of pure PVF 2 from the melt at atmospheric pressure was described by Lovinger [14] based on epitaxial growth on the surface of potassium bromide. However, no systematic investigation has been carried out on the temperature dependence of melt-grown/?-crystals.The purpose of this letter is to focus on the effects of quenching and then annealing on the /~-phase formation from the melt of PVF2 by means of FTIR, X-ray diffraction and electron microscopy.The PVF 2 (mol. wt = 5 x 105 ) utilized in this work was supplied by Polysciences, Inc. Films were either cast from cyclohexanone solutions on to glass plates or compression moulded. The thickness of the samples is about 5/~m for FTIR and X-ray diffraction analysis and about 100nm for electron microscopy studies. The two types of films were supported on a thin sheet of mica and were melted at 210°C for 10rain and then quenched quickly in a bath in the

show abstract

mentioning

confidence: 99%

β-phase formation of poly(vinylidene fluoride) from the melt induced by quenching

1987

View full text Add to dashboard Cite

show abstract

“…Ferroelectric polymers such as poly͑vinylidene fluoride͒ and its copolymers, a special class of ferroelectric materials, have been the subject of intense study for over 25 years, yielding a wealth of physical data, 3 and practical applications. 4 The structure of a random copolymer of vinylidene fluoride and trifluoroethylene, P͑VDF-TrFE͒, 5,6 is shown in the inset of Fig. 1.…”

mentioning

confidence: 99%

Novel switching phenomena in ferroelectric Langmuir–Blodgett films

Bune

Ducharme

Fridkin

et al. 1995

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…that the copolymer of vinylidene fluoride (VDF) and trifluoroethylene (TrFE) with TrFE content higher than 17 mol% crystallizes in polar form 1. 4 Yagi et a!. prepared these copolymers 5 • 6 over the entire range of comonomer content and observed the phase transition T:U below the melting point by differential scanning calorimetry (DSC) for copolymers with TrFE content less than 46 mol%.…”

mentioning

confidence: 99%

Dynamic Mechanical Dispersion in Copolymers of Vinylidene Fluoride and Trifluoroethylene

Murata

Koizumi

1985

Polym J

View full text Add to dashboard Cite

ABSTRACT:Copolymers of vinylidene fluoride (VDF) and trifluoroethylene (TrFE) with TrFE content ranging from 48 to lOOmol% were studied by dynamic mechanical measurements in a temperature range of 173 to 373 Kat 3.5 Hz. The IX and f3 dispersions were observed around 313 and 250 K in decreasing order of temperature and the T, dispersion occurred at higher temperature above the IX dispersion for copolymers with 48 to 71 mol% TrFE. It was inferred for copolymers with 48 to 71 mol% TrFE from the dependence of these dispersions on degree of crystallinity that the IX and f3 dispersions were due to micro-Brownian molecular motions ofTrFE rich and VDF rich sequences respectively in amorphous regions and that the T, dispersion was connected to the phase transition in crystalline regions. It was noted that the f3 dispersion in copolymer with higher TrFE content was related to the local molecular motions in amorphous and crystalline regions.KEY WORDS

show abstract

The polymorphism of poly(vinylidene fluoride). I. The effect of head-to-head structure

Cited by 277 publications

References 5 publications

β-phase formation of poly(vinylidene fluoride) from the melt induced by quenching

β-phase formation of poly(vinylidene fluoride) from the melt induced by quenching

Novel switching phenomena in ferroelectric Langmuir–Blodgett films

Dynamic Mechanical Dispersion in Copolymers of Vinylidene Fluoride and Trifluoroethylene

Contact Info

Product

Resources

About