Title :
Dynamics of poling PVDF between 250 degrees C and 120 degrees C
Author :
Eberle, G. ; Eisenmenger, G. Eberle W
Author_Institution :
Physikalisches Inst., Stuttgart Univ., Germany
Abstract :
PVDF films with high beta -content are poled in an electric field of 60 MV/m at temperatures between 25 degrees C and 120 degrees C. At 25 degrees C the alignment of dipoles takes place in a central poling zone during several hours of poling. When the temperature is increased to 120 degrees C the poling time necessary to align the dipoles in this narrow zone is reduced to several seconds. In addition, at temperatures higher than 90 degrees C and increased poling times the central poling zone first increases but later decreases in its dielectric displacement. Simultaneously in a 10 mu m regime adjoining the positive electrode a secondary displacement zone starts to grow. The strong reduction of this peak under short circuit conditions indicates hetero-charge accumulation in front of an anode.<>
Keywords :
dielectric polarisation; electrets; polymer films; 25 to 120 degC; dielectric displacement; dipole alignment; electret; hetero-charge accumulation; poling PVDF; poling time; secondary displacement zone; Acoustic propagation; Coupling circuits; Crystallization; Current measurement; Electrodes; Oscilloscopes; Polarization; Positron emission tomography; Temperature; Thickness measurement;
Conference_Titel :
Electrets, 1991. (ISE 7) Proceedings., 7th International Symposium on (Cat. No.91CH3029-6)
Conference_Location :
Berlin, Germany
Print_ISBN :
0-7803-0112-9
DOI :
10.1109/ISE.1991.167242
