Please use this identifier to cite or link to this item: http://dx.doi.org/10.18419/opus-4948
|Title:||Polarization distributions in isotropic, stretched or annealed PVDF films|
|metadata.ubs.publikation.source:||Das-Gupta, Dilip K. (Hrsg.): Proceedings / 6th International Symposium on Electrets : ISE 6; 1-3 Sept. 1988, The Queen's College, Oxford, England. Piscataway, NJ : IEEE, 1988, S. 13-17|
|Abstract:||The spatial distribution of the polarization in polyvinylidene fluoride (PVDF) films was measured at room temperature with the PPS (piezoelectric pressure step) method. In order to investigate the time development under external fields, a thin insulation polyethylene terephthalate (PET) film covering an evaporated aluminium electrode was inserted between the sample and the measuring electrode. The observed development of inhomogeneous and internal polarization zones is attributed to charge injection and charge trapping at the polarization zone boundaries. The polarization zone develops at a position where the critical field strength for dipole orientation in the crystallites is exceeded by the approach of injected homocharges (or without injection by the depletion of internal homocharges and the excess of heterocharges). The critical field for α-crystallites corresponds to an electric field phase transition at 1.2 MV/cm. The development of central polarization zones in PVDF containing β-crystallites indicates injection of charges with both signs and almost equal mobility. The results indicate that the β-crystallites determine the charge injection rate or the mobility or both.|
|Appears in Collections:||08 Fakultät Mathematik und Physik|
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