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The effect of crystal polymorphism of ferroelectric copolymer vinylidene fluoride-hexafluoropropylene on its high-voltage polarization |
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| Authors: | Valentin V Kochervinskii Inna A Malyshkina Dmitry A Kiselev Tatiana S Ilina Nina V Kozlova Nina A Shmakova Alexander A Korlyukov Margaret A Gradova Sergey A Bedin |
| Affiliation: | 1. State Research Center of the Russian Federation, Karpov Institute of Physical Chemistry, Moscow, Russia;2. Faculty of Physics, Moscow State University, Moscow, Russia;3. Department of Materials Science of Semiconductors and Dielectrics, National University of Science and Technology “MISiS”, Moscow, Russia;4. State Research Center of the Russian Federation, Karpov Institute of Physical Chemistry, Moscow, Russia
Laboratory of Irradiation Modification of Polymers, Enikolopov Institute of Synthetic Polymeric Materials RAS, Moscow, Russia;5. Laboratory for X-Ray Diffraction Studies, A.N. Nesmeyanov Institute of Organoelement Compounds RAS, Moscow, Russia;6. Department of Dynamics of Chemical and Biological Processes, Semenov Institute of Chemical Physics RAS, Moscow, Russia;7. Educational and Scientific Center of Functional and Nanomaterials, Moscow State Pedagogical University, Moscow, Russia |
| Abstract: | Dielectric response of vinylidene fluoride-hexafluoropropylene copolymer, crystallized in different polymorph modifications, to a high-voltage electric field was studied. Polarization switching at high electric fields below coercive was detected. It was found that crystallization of the copolymer predominantly in nonpolar α-phase is accompanied by more intensive growth of electric displacement at polarization. For the sample with higher content of polar γ-phase, the value of high-voltage conductivity “anomalously” decreased with increasing field at fields above coercive. The data on the field dependences of the remnant polarization showed that this should be attributed to an increase of the effective capture cross section of deep traps of γ-phase polar planes for impurity and injected carriers. X-ray diffraction has revealed the field-induced transition of a part of the chains of the amorphous phase to the crystal. |
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