| With the development of wearable electronic devices,flexible ferroelectric composite materials,which have the functions of energy harvesting,energy storage,detection and so on,have drawn much attention.However,the poor ferroelectric properties compared with ceramic materials make it hard for composites to meet the requirement of novel devices,so how to improve the properties of composites has been an important problem.This work studied the effect of external force on the ferroelectricity and pyroelectricity of PVDF and1-3 PVDF-based composites.The details are shown as follow:First,the effect of different uniaxial stretching grafts on the ferroelectric and pyroelectric properties of PVDF was studied.When the stretching ratio was 5,the temperature was 90oC and the stretching velocity was 10 mm/min,the content of?phase reached the maximum value of 74.5%.Meanwhile,the saturated polarization and the remanent polarization had the maximum value of 9.23?C/cm2 and 6.20?C/cm2,respectively,and the pyroelectric coefficient was maximum,which was 1.38×10-9 C·cm-2·K-1 at 45 oC.Second,the 1-3 lead zirconate titanate?PZT?/PVDF composites were uniaxial stretched,and the improvement of their pyroelectric figure of merit was studied.The result showed that the stretching both induced the?phase in PVDF and orientated the nanowires.When the content of PZT nanowires was 30 wt%,the pyroelectric coefficient increased to 4.23×10-9 C·cm-2·K-11 and the figure of merit increased to 2.18×10-10 C·cm-2·K-1,which was 5.3 times and 6.2 times larger than that of unstretched samples,respectively.Finally,aiming at the problem of the nanowire orientation in organic matrix,huge magnetic field were applied on the 1-3 manganese-doped lead zirconate titanate?PMZT?/PVDF composites.The effect on orientation of inorganic phase,the matrix,the ferroelectricity and dielectric properties was exploringly studied.When the magnetic field was 7.875 T,the treatment time was 20 min and the treatment temperature was 140 oC,the polarization of samples reached the maximum,the value of which was 2.01?C/cm2 at 110MV/m. |
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