Investigation on crystalline structure and dielectric relaxation behaviors of hot pressed poly(vinylidene fluoride) film |
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Authors: | Xubo Jiang Xiaojia Zhao Guirong Peng Wenpei Liu Ke Liu Zaiji Zhan |
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Institution: | State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, People''s Republic of China |
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Abstract: | The dielectric relaxation behaviors of hot pressed poly(vinylidene fluoride) (PVDF) film have been studied using dielectric spectroscopy in the frequency domain from 20 Hz to 5 MHz at temperatures between 20 °C and 200 °C. Crystalline/amorphous interphase is suggested with methods of FTIR, XRD, and DSC. Frequency and temperature dependence of dielectric spectroscopy reveals the relaxation behavior and structural dynamics of the samples, and three types of relaxation processes are suggested, αAc relaxation process contributed by the hopping transport process near the periphery of conduction band or valence zones at Fermi energy, αc relaxation process related to the structure change of crystal lattice trapped dipoles in crystalline regions, and αa relaxation process arising from segmental dipole rearrangement of interphases in amorphous regions. Cole-Cole and Havriliak-Negami experimental equations were utilized to analyze these relaxation processes, and differences of Arrhenius parameters for αAc and αc relaxation processes obtained from Cole-Cole and Havriliak-Negami equations were discussed in detail. Activity energy of different relaxation processes obtained from Arrhenius equation and VFT equation indicates non-single thermal activation mechanism for hot pressed PVDF film. |
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Keywords: | Poly(vinylidene fluoride) Dielectric relaxation Crystalline structure Interphases Ac conductivity |
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