The ageing of corona charged polyvinylidenefluoride (PVF2)

The effect of ageing due to annealing of corona charged PVF2 films has been studied by observations of (i) changes in the X-ray diffraction patterns and (ii) decay of the piezoelectric strain coefficient d31. Annealing at progressively higher temperatures was observed to produce a gradual depolarization although considerable piezoelectricity was still remanent even at 150°C, The structural morphology of the corona charged PVF2 was not significantly altered by annealing at temperatures up to 150°C.