Pockels effects of polyurea-5 film prepared by vapor-deposition polymerization

In order to investigate the ferroelectric properties of polyurea-5 prepared by vapor-deposition polymerization in comparison with those of polyvinylid ene fluoride (PVDF) and copolymers of vinylidene fluoride and trifluoroethy lene (P(VDF/TrFE)), the residual polarization P-r, the piezoelectric consta nt e(31) and the Pockels effects were measured. As a result, the P-r values of polyurea-5. PVDF, and P(VDF/TrFE) were obtained as 20 mC/m(2), 60 mC/m( 2) and 100 mC/m(2), respectively. On the other hand, polyurea-5, PVDF acid P(VDF/TrFE) showed e(31) of 5 mC/m(2); 60 mC/m(2) and 100 mC/m(2), respecti vely. We obtained P-r similar to e(31) in the case of P(VDF/TrFE) and PVDF. In the case of P(VDF/TrFE) and PVDF, P-r similar to e(31) has been reporte d by many researchers. However, in the case of polyurea-5, P-r > e(31) was obtained. The e(31) of polyurea-5 is about 1/20 that of P(VDF/TrFE). Also, to measure the Pockels effects of polyurea-5 films, a laser beam was introd uced parallel and perpendicular to the thickness of the polyurea-5 him whic h was poled at room temperature. As a result, the Pockels coefficient of th e polyurea-5 film was obtained to be 0.09 pm/V, which was approximately 1/4 that of PVDF or P(VDF/TrFE) films. however, this value is fairly large for polymers.