Influence of the relative humidity on the properties of ferroelectric poly(vinylidene fluoride-trifluoroethylene)

Abstract

Articles you may be interested inThe effect of electroactive interlayer on the ferroelectric properties in poly(vinylidene fluoride-trifluoroethylene) copolymer ultrathin films J. Appl. Phys. 112, 074111 (2012); 10.1063/1.4757936High-temperature ferroelectric behaviors of poly(vinylidene fluoride-trifluoroethylene) copolymer ultrathin films with electroactive interlayers Interacting and noninteracting dipole systems in ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymer J. Appl. Phys. 108, 084109 (2010); 10.1063/1.3499614Domain stabilization effect of interlayer on ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymer ultrathin film Ultrathin films of poly͑vinylidene fluoride-trifluoroethylene͒ copolymers were prepared by the Langmuir-Blodgett technique. These films show a hysteresis loop of the polarization versus the applied electrical field in a dry atmosphere which can be attributed to a ferroelectric phase. By increasing the relative humidity in the surrounding atmosphere, water molecules are absorbed by the samples yielding quasi-free charge carriers. These charges can fluctuate between the electrodes of the samples and build a space charge polarization superimposed to the ferroelectric polarization. Therefore, the hysteresis loops at low frequencies, where the quasi-free charges can contribute to the total polarization, are broadened and the measured remanent polarization is increased. Also, the real and the imaginary parts of the dielectric permittivity of the samples in the low frequency range are increased. Additionally, the transient decay of the retained charge is more pronounced for higher relative humidities. Furthermore, the transient desorption of the water from the polymer is measured by detection of the rapidly changed relative humidity. However, ellipsometric measurements show only a small increase in the sample thickness and no significant change in the refractive index due to the absorption of water.

Polarization of block textured films of ferroelectric copolymers of vinylidene fluoride with tetrafluoroethylene in an external field

“…These bonds, as new functional groups found on the surface after the polarization, can cause changes in the characteristics of the near electrode polarization. In addition, the presented data make it possible to esti mate the problem of water adsorption on the surface of the ferroelectric polymer stated in the literature [49,50]. For this purpose, the surfaces of the initial film and polarized film were investigated in the frequency range 3200-3600 cm -1 , where the copolymer does not have characteristic absorption bands and the water molecules absorb strongly.…”

Broadband dielectric relaxation spectra of PVDF copolymer films

“…The dielectric relaxation spectra in the frequency range with variation of the temperature during the heating process for the 28 nm sample are shown in figures 3(a) and 3(b). Also for these samples a dielectric relaxation is found in the high frequency range [1,[3][4][5]. The relaxation time depends on the temperature and decreases with increasing temperature.…”

Interacting and noninteracting dipole systems in ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymer

“…12,13,15 In the time domain a corresponding Kohlrausch behavior of the polarization current j ϰ t −␣͑T͒ is observed. 12,13,15 In the time domain a corresponding Kohlrausch behavior of the polarization current j ϰ t −␣͑T͒ is observed.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] This material shows ferroelectric properties like hysteresis loops with a remanent polarization of about 10 C / cm 2 . [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] This material shows ferroelectric properties like hysteresis loops with a remanent polarization of about 10 C / cm 2 .…”