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 invest igate the ferroelectric properties of polyurea-5, we measured switchin g behavior. Switching phenomena were observed for the polymer thin fil ms at room temperature. It was found that the switching time depends o n the applied electric field E, and that the amount of reversed polari zation is nearly independent of E. The results clearly revealed charac teristics of ferroelectric switching phenomena. As a result; we obtain ed 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 swi tching curves is broad, compared to those of typical ferroelectric pol ymers, vinylidene fluoride and trifluoroethylene copolymers.