| In the present study,the melting recrystallization behavior of polyvinylidene fluoride(PVDF)were studied by transmission electron microscope(TEM)and fourier transform infrared spectroscopy(FTIR).And demonstrate all-polymer ferroelectric capacitor memory device in a structure of metal-ferroelectric polymer-metal by using highly oriented PVDF film.It was found that carbon-coated PVDF film exhibited highly orientation after melt-recrystallization process.In contrast PVDF film without carbon film exhibited disorder structure after same process.It is due to the existence of vacuum evaporated carbon film and as a result the molecular chain on the surface of the film was fixed.Vacuum evaporate carbon film stop the orientation in the surface from relaxation.In the isothermal crystallization process in 160 ?,the sample fixed by vacuum evaporated carbon film grew into ? form edge-on lamellae,while sample without carbon film grew into flat-on ? form lamellae.When using ? form flat-on lamellae as raw material,we can get flat-on y form lamellae as well.Taking advantage of the properties mentioned above,use highly oriented edge-on lamellae PVDF film as raw material,we get edge-ony form lamellae for the first time.This procedure is a combined action of high temperature crystallization and orientation fixing.By adjusting the stretching temperature and stretching rate,we got highly oriented PVDF film with extensive ? form concentration.The c-axis of edge-on ? form parallel to stretching direction with a-axis and b-axis rotate around it.Fabricating ferroelectric capacitor by one-step method and testing its properties.The PVDF ferroelectric device show excellent performance with a maximum remnant polarization?7.3?C/cm2,low coercive fields(150Mv/m),low leakage and good fatigue performance. |
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