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PVDF Films (pvdf + film)

Distribution by Scientific Domains
Polymers and Materials Science75%

Selected Abstracts

Solar-thermochromism of Pseudocrystalline Nanodroplets of Ionic Liquid,NiII Complexes Immobilized inside Translucent Microporous PVDF Films

ADVANCED MATERIALS, Issue 7 2009
Xianjun Wei
Translucent composite films of poly(vinylidene fluoride), ionic liquid, and nickel complexes are successfully fabricated using thermal modulation of dissolution, casting, and drying. These films exhibit high stability in ambient storage and reversible thermochromic responses in air at temperatures achievable under sunlight, promising intelligent windows for controlling solar heat entering the built environment. [source]

Single Radiation-Induced Grafting Method for the Preparation of Two Proton- and Lithium Ion-Conducting Membranes

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 8 2006
Mohamed Mahmoud Nasef
Abstract Summary: Two distinct types of polymer electrolyte membranes for conducting protons and lithium ions have been prepared by a radiation-induced grafting method. The polymer electrolyte precursor (PVDF- g -PS) is obtained by the simultaneous grafting of styrene onto poly(vinylidene fluoride) (PVDF) followed by one of two specific treatments. This includes sulfonation with a chlorosulfonic acid/dichloromethane mixture to obtain proton (H+)-conducting membranes, or activation with LiPF6/EC/DC liquid electrolyte to obtain lithium ion (Li+)-conducting membranes. The chemical structure of the obtained electrolyte membranes is verified by FT-IR spectroscopy. Differential scanning calorimetry is used to examine the changes in the crystallinity and the thermal properties of both electrolyte membranes during the preparation process. The thermal stability of both electrolyte membranes is also evaluated using thermal gravimetrical analysis. The obtained polymer electrolyte membranes achieve superior conductivity values: 1.61,×,10,3 S,·,cm,1 for Li+ and 5.95,×,10,2 S,·,cm,1 for H+ at room temperature at a polystyrene content of 50%. The results of this work suggest that high quality H+ - and Li+ -conducting membranes can be obtained using a single radiation-induced grafting method. Schematic representation of the single root for preparation of Li+ - and H+ -conducting membranes started by radiation-induced grafting of styrene onto a PVDF film followed by chemical treatment. [source]

Effect of NaCl filler on ferroelectric phase and polaron configurations of PVDF films

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2007
I. S. ElashmawiArticle first published online: 8 MAR 200
Abstract Polyvinyldene fluoride (PVDF) films filled with NaCl of mass fraction range 1 , W , 6 % were prepared by casting technique. Their crystalline structure, thermal, optical properties and Electron spin resonance (ESR) were examined. X-ray diffraction (XRD) and differential thermal analysis (DTA) measurements indicated a maximum ferroelectric ,-phase increment at 4%. DTA was used to identify the phase transition temperatures, the order of reaction and the activation energy of melting. The UV-Visible optical absorption implied a minimum value of the estimated optical energy gap at W = 4%. ESR spectra contained a Lorentizian signal exhibiting a minimum value of the symmetry factor at W = 4%. The energy levels of the optical gap boundaries were though to contribute to ESR transitions. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Studies on , to , phase transformations in mechanically deformed PVDF films

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010
Vijayakumar R. P.
Abstract PVDF cast films were drawn at different temperatures to different draw ratios at constant draw rate to understand the mechanism of , to , phase transformation during mechanical deformation. WAXD and FTIR studies were carried out to determine the formation and content of , phase in the drawn films. Lower stretch temperatures gave higher fractions of , phase. The cast PVDF films were also drawn at suitable temperatures below the PVDF ambient melting point to the draw ratio of 6.4. The highest fraction of , phase obtained in these ultra drawn films was 0.98. SALS studies carried out for films at different stretch ratios show the change in spherulitic structure with the stretching parameters and give information for the understanding of phase transformation during stretching of PVDF films. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]