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

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 β-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.

Fourier transform infrared and ultraviolet-visible investigation of swift heavy 100 MeV Ag-ion- and 75 MeV oxygen-ion-irradiated polyvinylidene fluoride thin films

“…The UV-visible spectra of pristine films (Fig. 4) do not show any absorption peak, but only a sharp edge around 200 nm and a shoulder around 222 nm, which confirms the earlier results of pristine PVDF [31]. On irradiation, the intensity of the sharp absorption edge increases and its position gets slightly shifted towards higher wavelength/lower frequency (Figs 4(d) and 5).…”

Phase transformation mechanisms and piezoelectric properties of poly(vinylidene fluoride)/montmorillonite composite

“…For example, the β phase of PVDF has been obtained by crystallization from certain solution,4 by drawing films containing α phase,5, 6 by crystallization from solution under special conditions,7 or by induced by special substrate 8. Incorporation of halide9, 10 and carbon tubes11–13 can also resulted in beta phase, thermal and electrical variation of PVDF. Yu et al14 and Yu and Cebe15 also have observed that the addition of montmorillonite (MMT) led to beta phase of PVDF.…”

Metal Salt‐Induced Ferroelectric Crystalline Phase in Poly(vinylidene fluoride) Films

“…Though quite a few reports have dealt with the effect of selected additives on the structural properties of PVDF,10–16 to the best of our knowledge, no previous studies have reported the effect of CaCl 2 salt on PVDF films, and more specifically on the ferroelectric characteristics of PVDF–CaCl 2 as‐cast films. Some of the reasons for using metals salts such as CaCl 2 in neat PVDF samples are: cost‐effective processing with simple methodology (for solution‐cast films) and removal of metal salts by washing the films in de‐ionized water.…”