Dielectric behavior and structural characterization of polymeric double layer thin films

Abstract

In the present work, various techniques have been employed to investigate the polarization processes along with the estimation of various parameters involved therein in polymethylmethacrylate (PMMA), polyvinylidenefluoride (PVDF), and PVDF‐PMMA double‐layered samples. Anticipating the difficulty to analyze the experimental data; in such complicated situation, when in one the same temperature range various decay mechanism may complete, the different techniques are used to interpret the experimental results. These measurements verify the various processes responsible polarization in these polymer samples. The structural morphology, crystallinity, atomic, and molecular geometry were analyzed using different characterization tools, namely SEM, XRD, FTIR, and DSC; therefore, the results were found to be in confirmation with amorphous nature of PMMA and semicrystalline nature of PVDF and PVDF‐PMMA double‐layered samples. Ac dielectric measurements were performed for different temperatures over the frequency range of 100 Hz to 10 kHz. Dielectric losses have also been recorded with a two terminal (Al‐Al) electrode combination. The study revealed that both interfacial phenomena and space charge mechanism are known to play preliminary role in the dielectric behavior of double‐layered samples. The amorphous–crystalline interface act as charge‐carrier trapping sites in this polymeric heterogeneous system. Dielectric permittivity and dielectric loss of the double‐layered sample depend manifolds on the temperature and the Ac frequency. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47724.

Analysis of dielectric behavior of PVDF: PSF polyblends at lower frequency range from measurements of transient absorption and desorption currents

“…The polymer films were carefully pulled away from the glass plate. PVDF: PSF weight percentage ratios of 90:10, 70:30, and 50:50 were used to make polyblend films of various compositions 11–14 . The prepared circular films had a thickness of 50 μm and a diameter of 5 cm.…”

“…PVDF: PSF weight percentage ratios of 90:10, 70:30, and 50:50 were used to make polyblend films of various compositions. [11][12][13][14] The prepared circular films had a thickness of 50 μm and a diameter of 5 cm. To create the ohmic contact, both surfaces of the polymer blend samples were vacuum aluminized using a Hindhivac Vacuum coating unit with Penning and Pirani pressure gauges, ST-A6P3, over a central circular region of 3.5 cm in diameter.…”