Polarization profiles have been measured with a resolution of about 2
mu m in corona poled 95:5 P(VDF-TFE) copolymer by using the piezoelect
rically induced pressure step (PPS) method. A polarization peak is obs
erved near the positive side of samples poled in a negative corona by
the constant current technique. The distribution of polarization is al
so nonuniform in the case of a constant voltage poling at 50 MV m(-1),
but profiles are rather uniform if a 100 MV m(-1) poling field is app
lied at 85 degrees C. In muitilayer samples, the upper film bombarded
by corona ions remains absolutely nonpolarized. Thin transition nonpol
arized zones are seen near surfaces of even well polarized P(VDF-TFE).
It is shown that polarization uniformity in P(VDF-TFE) is strongly af
fected by injection of negative charge carriers from the virtual elect
rode formed either on the surface bombarded by corona ions, or between
two contacting dielectric surfaces. Our data on P(VDF-TFE) are in acc
ord with those reported on other ferroelectric polymers.