The dependence of polarization fatigue on crystallinity of vinylidene fluoride and trifluoroethylene copolymer films was studied.Experimental data indicated that the higher the crystallinity of the film was,the slower...The dependence of polarization fatigue on crystallinity of vinylidene fluoride and trifluoroethylene copolymer films was studied.Experimental data indicated that the higher the crystallinity of the film was,the slower the fatigue rate of the film became.A possible explanation was put forward,and it was regarded that the space charges,trapped at the boundaries of crystallites and/or captured by the defects lying both in amorphous and crystalline phases,should make the major contribution to polarization fatig...展开更多
This paper investigates the influences of polarization fatigue on remanent polarization and switching time by pulse train measurements in ferroelectric poly（vinylidene fluoride （78%） and trifluoroethylene （22%））...This paper investigates the influences of polarization fatigue on remanent polarization and switching time by pulse train measurements in ferroelectric poly（vinylidene fluoride （78%） and trifluoroethylene （22%）） thin films. Fatigue was carried out by a series of bipolar switching pulses with constant pulse width （on-time） and various interval times between pulses （off-time）. The experimental observations indicated that the off-time period showed no obvious influence on fatigue rate and the switching time increased with the increase of fatigue cycles. The origination of these phenomena was discussed according to the charge injection model.展开更多
The electromechanical behavior of poly(vinylidene fluoride-trifluoroethylene)[P(VDF -TrFE)]ferroelectric thin film was investigated using the three dimensional(3D) phase-field method. Various energetic contributions,i...The electromechanical behavior of poly(vinylidene fluoride-trifluoroethylene)[P(VDF -TrFE)]ferroelectric thin film was investigated using the three dimensional(3D) phase-field method. Various energetic contributions,including elastic,electrostatic,and domain wall energy were taken into account in the variational functional of the phase field model.Evolution of the microscopic domain structures of P(VDF-TrFE) polymer film was simulated.Effects of the in-plane residual stress,the film thickness and externally applied electric bias field on the electromechanical properties of the film were explored.The obtained numerical results showed that the macroscopic responses of the electric hysteresis loops are sensitive to the residual stress and electric bias field.It was also found that thickness has a great effect on the electric hysteresis loops and remanent polarization.展开更多
基金supported by Science and Technology Commission of Shanghai Municipality(No.0652NM028)ShanghaiLeading Academic Discipline Project(No.B113)+1 种基金National Natural Science Foundation of China(No.10804020)Specialized Research Fund for the Doctoral Program of Higher Education of China(No.200802461088).
文摘The dependence of polarization fatigue on crystallinity of vinylidene fluoride and trifluoroethylene copolymer films was studied.Experimental data indicated that the higher the crystallinity of the film was,the slower the fatigue rate of the film became.A possible explanation was put forward,and it was regarded that the space charges,trapped at the boundaries of crystallites and/or captured by the defects lying both in amorphous and crystalline phases,should make the major contribution to polarization fatig...
基金Project supported by the National Natural Science Foundation of China (Grant No. 10804020)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 200802461088)
文摘This paper investigates the influences of polarization fatigue on remanent polarization and switching time by pulse train measurements in ferroelectric poly（vinylidene fluoride （78%） and trifluoroethylene （22%）） thin films. Fatigue was carried out by a series of bipolar switching pulses with constant pulse width （on-time） and various interval times between pulses （off-time）. The experimental observations indicated that the off-time period showed no obvious influence on fatigue rate and the switching time increased with the increase of fatigue cycles. The origination of these phenomena was discussed according to the charge injection model.
基金supported by the National Natural Science Foundation of China(Grant Nos.11072127, and 10832002)the National Basic Research Pro- gram of China(Grant No.2011CB610300)
文摘The electromechanical behavior of poly(vinylidene fluoride-trifluoroethylene)[P(VDF -TrFE)]ferroelectric thin film was investigated using the three dimensional(3D) phase-field method. Various energetic contributions,including elastic,electrostatic,and domain wall energy were taken into account in the variational functional of the phase field model.Evolution of the microscopic domain structures of P(VDF-TrFE) polymer film was simulated.Effects of the in-plane residual stress,the film thickness and externally applied electric bias field on the electromechanical properties of the film were explored.The obtained numerical results showed that the macroscopic responses of the electric hysteresis loops are sensitive to the residual stress and electric bias field.It was also found that thickness has a great effect on the electric hysteresis loops and remanent polarization.
