Enhancement of β phase crystallization and dielectric behavior of kaolinite/halloysite modified poly(vinylidene fluoride) thin films

The Poly(vinylidene) fluoride (PVDF) thin films with a high content of β-phase were prepared by controlling heat-treatment temperature using casting from the poled solvents. The crystallite microstructure of thin films was depicted by the techniques of X-ray diffraction and FTIR. The results showed that heat treatment was favorable for inducing the β- and γ-phase formation of PVDF. The β phase films were obtained with heat treatment at temperatures ranging from 60°C to 120°C and annealing at 120°C after casting from DMF. The thermo-optical effect of β phase PVDF films was investigated using a spectroscopic ellipsometer. At temperatures ranging from 20°C to 100°C, the refractive index of PVDF was negatively correlated with the temperature between 350 and 1500 nm. The value of the t.o. coefficient of PVDF films was calculated at all temperatures. The maximum value of the t.o. coefficient was about 3.3 × 10-4/°C at the ascending stage of temperature and 3.0 × 10-4/°C at the descending stage of temperature. Therefore, it is possible to use the thermo-optic effect of the β phase PVDF for long wavelength infrared imaging.

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Effect of in situ synthesized Fe2O3and Co3O4nanoparticles on electroactive β phase crystallization and dielectric properties of poly(vinylidene fluoride) thin films

Physical Chemistry Chemical Physics ◽

10.1039/c4cp04006f ◽

2015 ◽

Vol 17 (2) ◽

pp. 1368-1378 ◽

Cited By ~ 70

Author(s):

Pradip Thakur ◽

Arpan Kool ◽

Biswajoy Bagchi ◽

Sukhen Das ◽

Papiya Nandy

Keyword(s):

Thin Films ◽

Dielectric Properties ◽

Vinylidene Fluoride ◽

Dielectric Constants ◽

Β Phase ◽

Poly Vinylidene Fluoride

In situsynthesis of Fe2O3–Co3O4nanoparticles stabilized electroactive PVDF thin films with colossal dielectric constants.

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Dielectric Behavior of PVDF/PP-PT Nanocomposite Thin Films

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1002.11 ◽

2014 ◽

Vol 1002 ◽

pp. 11-16

Author(s):

Ting Ting Yu ◽

Zhao Hui Ren ◽

Si Min Yin ◽

Xin Yang ◽

Yi Feng Yu ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Dielectric Constant ◽

Vinylidene Fluoride ◽

Low Frequency ◽

Weight Ratio ◽

Dielectric Behavior ◽

Β Phase ◽

Nanocomposite Thin Films ◽

Coating Method

PVA/PVP-assisted hydrothermal method was used to prepare single-crystal pre-perovskite PbTiO3(PP-PT) nanofibers, in which polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) acted as surfactants. Subsequently, poly (vinylidene fluoride)/ pre-perovskite PbTiO3nanofibers (PVDF/PP-PT) nanocomposite thin films were successfully fabricated by a spin-coating method. The test results showed that PP-PT nanofibers had a good distribution in PVDF matrix. Moreover, α-phase coexisted with β-phase in the PVDF and PVDF/PP-PT nanocomposite thin films. The dielectric properties of the PVDF/PP-PT nanocomposite thin films were measured as a function of frequency in the range of 5 kHz to 5 MHz. It is worth noting that the dielectric constant of nanocomposite thin films increased with increasing the weight ratio of PP-PT nanofibers in the low frequency range. By contrast, the dielectric constant of PVDF/PP-PT nanocomposite thin film which contained 20% PP-PT nanofibers was 43.7% larger than that of pure PVDF thin film (εr= 6.77) at 5 kHz, and the loss tangent was ~0.03.

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