Ferroelectric switching behavior in thin films of polyurea-5

Thin polyurea-5 films were prepared by vapor-deposition polymerization of 1,5-diaminopentane and 1,5- diisocyanatepentane. In order to investigate the ferroelectric properties of polyurea-5, we measured switching behavior. Switching phenomena were observed for the polymer thin films at room temperature. It was found that the switching time depends on the applied electric field E , and that the amount of reversed polarization is nearly independent of E . The results clearly revealed characteristics of ferroelectric switching phenomena. As a result, we obtained a residual polarization of about 20 mC/m 2 at room temperature. We found also that the switching time is long, and that the shape of switching curves is broad, compared to those of typical ferroelectric polymers, vinylidene fluoride and trifluoroethylene copolymers.