Novel fluoro-polymer electret: Poly(vinylidenfluoride-hexafluoroisobutylene)

Poly(vinylidene fluoride)(PVDF), VDF copolymers and odd nylons have been reported to be typical ferroelectric crystalline polymers by many researchers. However, these ferroelectric polymers have no stability electrically and thermally as commercial devices. The application of electronic device by the polymers is limited. Poly(vinylidenefluoride-hexafluoroisbutylene) P(VDF-HFIB), which is easily synthesized by radical polymerization, have a good mechanical properties and thermal properties. P(VDF-HFIB)s are melt-processable, retain their mechanical strength at high temperature, and resist attacking by corrosive agents and solvents. This copolymers can make the crystal and have a higher crystallinity. If the chain with a planar zigzag conformation in these copolymers is formed, dipoles can align in the same direction. The monomer dipole moment of P(VDF-HFIB) is about 2.8 Debye. If a higher electric field is applied to the sample at high temperature, the resultant crystals in the polymer can adopt a metastable polar form showing ferroelectric behavior. In this paper, we discuss ferroelectric properties in P(VDF-HFIB).