High electric tunability of relaxor ferroelectric Langmuir-Blodgett terpolymer films

Poly(vinylidene fluoride-trifluoroethylene-chlorofloroethylene) terpolymer films have been fabricated on Al-coated polyimide substrates using the Langmuir-Blodgett (LB) technology. The electrical properties of the films have been investigated from 150 to 350 K. The temperature of the dielectric maximum and the measured frequency obeys the Vogel-Fulcher [J. Am. Ceram. Soc. 8, 339 (1925); Phys. Z. 22, 645 (1921)] law. The electric tunabilities of the films at room temperature are 42.6% and 80% under 50 and 240 MV/m, respectively. The reasons for the high tunability are discussed based on the special microstructure of the LB films.