Piezoelectricity uniaxially oriented film

Table 2 gives the 0 (111) values for various highly oriented films. The pola izing process produces about 28% of 30 orientation and d = 2.3 for the uniaxially oriented film. On the other hand, it produces about 43% of 30 orientation and d -=1.0 for the 90 -oriented film. Since the 30°-orienta-tion for the latter film is by far sharper than that for the former film, the orientation is not parallel to the piezoelectricity. 

The relationship between the piezoelectricity and the orientation of dipoles were investigated using the uniaxially oriented film. The film has the lowest highly orientation and the increase in the orientation can be easily seen. Now, an orientation parameter, 0 (b) is defined as the ratio of the amount of oriented crystallites to that of whole crystallites. ... 

Wu et al. [24) studied the effects of anisotropy and absorbed water on piezoelectric properties of nylon-9 and nylon-11. The piezoelectric measurements on polymorphs of nylon-ll and nylon-9 were carried out at various poling fields and temperatures. Piezoelectric constant for uniaxially stretched and poled a-nylon-9 was measured as a funetkw of angle between the orientation axis and applied tensile stress. The maximum piezoelectric constant dji was recorded when the tensile stress was applied in the extended direction, whereas the minimum ds was obtained when the stress was ap dicd to the film perpendicular to the extended duection. The d),/dj3 have a ratio of 10. Nylon-ll showed similar results. The angle dependence of the piezoelectiic constants and the ratio of djt/ dn were similar to the oriented form 1 PVDF film. 

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