Single crystals of poly(vinylidene fluoride)

Miller, Robert L.; Raisoni, J.

doi:10.1002/pol.1976.180141216

Cited by 63 publications

(30 citation statements)

References 7 publications

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“…Thus crystallisation from a 0.02% solution of PVDF in cyclohexanone is accompanied by the formation of a pseudohexagonal structure. 43 This was inferred from the ratio of the unit cell parameters: a/b = 1.73 (for the pseudohexagonal structure, a/b = y/3). Taking into account literature data, Miller and Raisoni 43 concluded (in contrast to Makarevich and Sushko 35 ) that PVDF crystallises as a mixture of p and y phases.…”

Section: A' A" A' A' A" A" A'mentioning

confidence: 99%

The structure and properties of block poly(vinylidene fluoride) and systems based on it

1996

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Section: A' A" A' A' A" A" A'mentioning

confidence: 99%

The structure and properties of block poly(vinylidene fluoride) and systems based on it

1996

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“…Thus, the b form has great technological utility and there have been numerous attempts to stabilize this phase. For example, the b form of the PVDF has been obtained by careful crystallization from solution, [13] by melt crystallization at high pressure, by application of a strong electric field, [14] by molecular epitaxy, [15] and by preparing a carbon-coated, highly oriented ultrathin film.[16] Earlier reports have indicated the possibility of stabilizing a phase of a crystalline polymer in the presence of well-dispersed layered silicates in the polymer matrix. Specifically, increases in the amount of the c phase in Nylon 6 [5±7] and the b phase in PVDF [3,4] nanocomposites have previously been observed.…”

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Dramatic Enhancements in Toughness of Polyvinylidene Fluoride Nanocomposites via Nanoclay‐Directed Crystal Structure and Morphology

et al. 2004

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Addition of nanoclays or other nanoparticles into various polymers to produce nanocomposites has been extensively utilized in an attempt to enhance the mechanical, physical, and thermal properties of polymers. While some interesting properties have been demonstrated, the resulting nanocomposites have yet to realize their full potential. Nanoparticles in general, and nanoclays in particular, with their nanometer size, high surface area, and the associated predominance of interfaces in the nanocomposites, can function as structure and morphology directors, for example stabilizing a metastable or conventionally inaccessible polymer phase, or introduce new energy dissipation mechanisms. Thus, what distinguishes nanoparticles from conventional micrometer-size rigid reinforcements is that their role might not be limited to only adding stiffness to the polymer, but also to directing morphology, as well as introducing new energy-dissipation mechanisms leading to enhanced toughness in the nanocomposites. Herein we demonstrate this potential by reporting a remarkable (order of magnitude) increase in toughness with a concurrent increase in stiffness in a poly(vinylidene fluoride) (PVDF) nanocomposite.The kinetics of crystallite growth and the details of crystallite morphology of semicrystalline polymers can be affected by the presence of layered silicates. [1,2] Although some changes in morphology have been described in polymer/nanoparticle hybrids, [3±7] near-total stabilization and control of a crystalline phase, coupled with dramatic enhancements in materials properties, has not yet been reported. PVDF is an important engineering plastic. It is used extensively in the pulp and paper industry due to its resistance to halogens and acids, in nuclear-waste processing for radiation-, and hot-acid applications, and in the chemical processing industry for chemical and high-temperature applications. It is also used in various device applications, due to its unique piezoelectric [8±10] and pyroelectric [11] properties. There are five known crystalline forms or polymorphs of PVDF: a, b, c, d, and e.[12] The a phase is the most common in melt crystallization, and remains the dominant crystalline form versus the b, and c phases. The c phase does not form except at high temperatures and pressures. Earlier reports have shown that the a phase (chain conformationÐtrans-gauche trans-gauche, tgis inactive with respect to piezo-and pyroelectric properties, while the b form (all trans) exhibits the most activity, and is thus the focus for electromechanical and electroacoustic transducer applications. Thus, the b form has great technological utility and there have been numerous attempts to stabilize this phase. For example, the b form of the PVDF has been obtained by careful crystallization from solution, [13] by melt crystallization at high pressure, by application of a strong electric field, [14] by molecular epitaxy, [15] and by preparing a carbon-coated, highly oriented ultrathin film.[16] Earlier reports have indicated the possibility...

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“…The significance of β and γ forms lies in its ability to transfer and even store ionic charge. Manufacturing method has great influence on the degree of crystallinity and amount of each phase [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Stretchable quaternary phasic PVDF-HFP nanocomposite films containing graphene-titania-SrTiO3 for mechanical energy harvesting

et al. 2018

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Integrating efficient energy harvesting materials in to soft, flexible, and eco-friendly substrates could yield significant breakthroughs in wearable and flexible electronics. Substantial advances are emerged in fabricating devices which can conform to irregular surfaces in addition to integrating piezoelectric polymer nanocomposites in to mechanical generators and bendable electronics. Here, we present a tri-phasic filler combination of one-dimensional titanium dioxide (TiO 2 ) nanotubes, twodimensional reduced graphene oxide, and three-dimensional strontium titanate (SrTiO 3 ), introduced in to a semi-crystalline polymer, poly(vinylidene fluoride-co-hexafluoropropylene). Simple mixing method was adopted for the composite fabrication after ensuring a high interaction between the various fillers. The prepared films were tested for their piezoelectric responses and mechanical stretchability. The results showed that the piezoelectric constant has increased due to the change in the filler concentration and reached a value of 7.52 pC/N at 1:2 filler combination. The output voltage obtained for the same filler composition was about 10.5 times that of the voltage generated by the neat polymer. Thus, we propose integration of these materials in fabricating energy conversion devices that can be useful in flexible and wearable electronics.

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Single crystals of poly(vinylidene fluoride)

Cited by 63 publications

References 7 publications

The structure and properties of block poly(vinylidene fluoride) and systems based on it

The structure and properties of block poly(vinylidene fluoride) and systems based on it

Dramatic Enhancements in Toughness of Polyvinylidene Fluoride Nanocomposites via Nanoclay‐Directed Crystal Structure and Morphology

Stretchable quaternary phasic PVDF-HFP nanocomposite films containing graphene-titania-SrTiO3 for mechanical energy harvesting

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