Journal ArticleDOI
Polymorphism of poly(vinylidene fluoride). III. The crystal structure of phase II
W. W. Doll,Jerome B. Lando +1 more
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In this paper, X-ray diffraction has been used to determine the crystal structure of poly(vinylidene fluoride) phase II, and three principal chain conformations were considered, which included two 21 helical forms [degenerate (planar) and nondegenerate] and the trans-gauche-trans-gaueche' form.Abstract:
In this study, X-ray diffraction has been used to determine the crystal structure of poly(vinylidene fluoride) phase II. Three principal chain conformations were considered, which included two 21 helical forms [degenerate (planar) and nondegenerate] and the trans-gauche-trans-gauche' form. An X-ray crystal structure determination has shown that the trans-gauche-trans-gauche' (TGTG′) conformation is the correct one for phase II. Experimental X-ray intensity data were taken at both −145° and 20° C in order to study the effect of temperature on the resulting structure. From the comparison between observed and calculated intensities, there are two possible crystal symmetries, P21 and P1, depending upon whether the two chains are taken to be antiparallel or parallel to one another. For both cases, the reliability indices for the chosen structure are almost identical. For either symmetry the unit cell is metrically orthorhombic (all angles equal to 90° within experimental error) with the following latt...read more
Citations
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Journal ArticleDOI
Electroactive phases of poly(vinylidene fluoride) : determination, processing and applications
TL;DR: In this article, the main characteristics of the electroactive phases of polyvinylidene fluoride and copolymers are summarized, and some interesting potential applications and processing challenges are discussed.
Journal ArticleDOI
Crystal Structures of Three Crystalline Forms of Poly(vinylidene fluoride)
TL;DR: In this article, an alternately-deflected molecular structure was proposed to release steric hindrance between the fluorine atoms along the chain, and a satistically disordered packing of such deflected chains satisfies the observed fiber period and improves appreciably the structure factor agreement.
Journal ArticleDOI
Electric‐field‐induced phase changes in poly(vinylidene fluoride)
TL;DR: The antipolar crystal form of poly(vinylidene fluoride) can be made piezoelectric and pyroelecric by the temporary application of electric fields in excess of 1 MV/cm at room temperature as discussed by the authors.
Journal ArticleDOI
A critical assessment of unbalanced surface stresses as the mechanical origin of twisting and scrolling of polymer crystals
Bernard Lotz,Stephen Z. D. Cheng +1 more
TL;DR: In this paper, the authors reviewed evidence that has accumulated in favor of lamellar twist induced by surface stresses that result from differential congestion of fold surfaces, as suggested initially (in 1984) and advocated for many years by Keith and Padden.
Book ChapterDOI
Poly(Vinylidene Fluoride)
TL;DR: In this paper, an extensive review of the important ferroelectric polymer poly(vinylidene fluoride) is presented, including polymerization, molecular structure, and defects; dilute-solution properties; crystalline structure of the various polymorphic phases, crystallization, and morphology.
References
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Journal ArticleDOI
Nuclear magnetic resonance and x‐ray determination of the structure of poly(vinylidene fluoride)
Journal ArticleDOI
The polymorphism of poly(vinylidene fluoride). I. The effect of head-to-head structure
J. B. Lando,W. W. Doll +1 more
TL;DR: In this paper, two polymorphic forms of poly(vinylidene fluoride), examined in this investigation, have different chain conformations. Chains in phase I have a planar zigzag conformation, while chains in phase II exhibit a 21 helical conformation.
Journal ArticleDOI
The Investigation of Synthetic Linear Polymers by X-rays.
TL;DR: In this paper, the authors present an approach to explain the properties of high polymeric substances in terms of their inner colloidal and molecular nature using x-Eay and electron diffraction investigations.
Journal ArticleDOI
Chain conformations of polyvinylidene fluoride as derived from its vibrational spectrum
G. Cortili,Giuseppe Zerbi +1 more
TL;DR: In this paper, it was shown that polyvinylidene fluoride can exist at least with two different conformations: a planar zig-zag poly (A) type chain, and a TATB type chain with a glide plane.