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Copolymers of vinylidene fluoride, VDF, and trifluoroethylene, TrFE, are representative ferroelectric polymers. Their local properties, such as domain structure and domain wall motion, are not well known because of its complex structure. In the isothermally crystallized samples, we can obtain lamellae that grow separately on the substrates. Then in order to discuss the local state of the polarization...
Annealing of thin copolymer films of vinylidene fluoride (VDF) and trifluoroethylene (TrFE) causes a strong increase in grain size as well as in crystallinity. It is known from AFM topographic images that flat-on lamella with diameters of up to 100 mum grow when thin films are annealed at temperatures around 140degC for several hours. To examine the orientation and the polarization state of the lamella,...
Piezoelectric response force microscopy, PFM, is a kind of SPM technique. It measures the change of the position of surface in accordance with the applied voltage, giving local piezoelectric activity. This method is widely applied to ferroelectric ceramics as well as to ferroelectric polymers. We used this method to study the dynamics of polarization reversal in thin films of VDF/TrFE copolymer.
The copolymer of vinylidene fluoride (VDF) with trifluoroethylene (TrFE) is a ferroelectric polymer undergoing polarization reversal as a result of rotational motions of molecules about their chain axes. It requires a very high electric field of approximately 100 MV/m for polarization reversal. Therefore, the thickness reduction below 50 nm is a technological requirement to achieve low-voltage operations...
Ferroelectric switching characteristics in vinylidene fluoride (VDF)/trifluoroethylene (TrFE) copolymer films have been shown to depend to a variety of factors not only the electric field E and temperature but also film thickness and previous poling conditions. Polarization reversal is believed to progress via nucleation-growth mechanism. However, there remains uncertainty about its microscopic features...
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