Ferroelectric polymer Langmuir films

For the first time switchable ferroelectric Langmuir-Blodgett films were prepared from the ferroelectric copolymer of vinylidene fluoride with trifluoroethylene P(VDF-TrFE). The film thickness was varied from 120 down to 2 monolayers of the copolymer, each monolayer being 5 Angstrom thick. The films show the first-order ferroelectric phase transition, switching the remanent polarization and pyroelectric effect. The remanent polarization measured for a film of 175 Angstrom thick is of the same order of magnitude as the value observed for the bulk of the same material P-s approximate to 0.1 C m(-2). The unusual temperature behaviour of the polarization leads to a rather high pyroelectric coefficient at room temperature, of the order of 400 mu C m(-2) K-1.