ISSN:
0098-1273
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The effects of poling temperature on piezoelectricity and its thermal stability were investigated on the basis of the thermal molecular motion associated with the crystalline region. This was done by using a film of highly oriented poly(vinylidene fluoride) containing form-I crystals. The film was prepared by a zone-drawing apparatus of the forced-quenching type. The piezoelectric stress constant e31 is a monotonically increasing function of the poling temperature which becomes steeper above ca. 320 K and again at ca. 400 K. The degree of orientation of the crystal b axis generated by poling also increases more steeply with poling temperature above ca. 320 K and again at 400 K. These temperatures correspond, respectively, to the crystalline dispersion temperature at 11 Hz, designated as αc, and the initiation temperature Tpm of large-scale molecular motion corresponding to premelting of form-I crystals. Thus the effect of poling temperature on piezoelectricity closely reflects the moleculer motion in form-I crystals. The annealing temperature T'a at which e31 decreases to 70% of that of unannealed sample by annealing a poled sample increases with the poling temperature and again this increase is steeper above poling temperatures of ca. 320 K and ca. 400 K. Thus the decay of piezoelectricity depends on both the αc temperature and Tpm.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1984.180220209
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