Effect of tricresyl phosphate doping on the remanent polarization in uniaxially oriented poly(vinylidene fluoride) films

Abstract

Abstract : Uniaxially stretched films of poly vinylidene fluoride were doped (1 wt. %) with plasticizer, tricrecyl phosphate (TCP). This slight doping with TCP was found to enhance the amount of remnant polarization in the region of low poling fields (e.g., from 1 to 6 mC/m2 under Ep =60 MV/m at 20 C) and high poling fields (e.g., from 57 to 66 mC/m2 under Ep = 200 MV/m at 20 C). The pyroelectric coefficient has shown that the doping enhances a quite stable (up to about 140 C) remnant polarization after high field poling (e.g., from 10.2 to 12.5 micro C/m2/K under Ep =200 MV/m at 20 C). This suggestive of a field induced increase in crystallinity. In addition, the switching of quasi-stable dipoles (those which randomize in the 90-140 C range) takes place at much lower electric fields than in undoped films. The present data suggest that a small amount of dopant in the noncrystalline regions greatly enhances ferroelectric dipole switching, possibly by acting in the interfacial zone between crystalline and amorphous regions.