| 초록 |
Ferroelectric polymeric materials such as poly vinylidene fluoride (PVDF) and its copolymer with trifluoroethylene (TrFE) are particularly of interest for non-volatile flexible memory application due to their large permanent polarization and ease of fabrication in thin films. As a semicrystalline polymer, it is well-known that the ferroelectric properties such as polarization and Curies temperature are mainly controlled by proper crystalline phase, which is β phase, as well as molecular chain orientation with respect to the electric field direction. We investigated the effect of solvents, co-solvents and additives on the microstructure and the resulting ferroelectricity of P(VDF-TrFE) copolymers in thin films. Several solvents such as DMF, DMSO, acetone and MEK and their co-solvents were used. Our experiments elucidate the relationship between the crystalline microstructure, thin film roughness and the polarization behavior of the ferroelectric polymers. The polymer thin films were characterized by X-Ray Diffractometer(XRD), Differential Scanning Calorimetry (DSC), Scanning and Transmission electron microscope(SEM and TEM) and ferroelectric hysteresis. Furthermore, we examined the possibility of fabricating micron scale patterns of the ferroelectric polymers with the controlled crystalline microstructure using various types of soft lithographic techniques such as micro-molding and capillary molding for potential micro-electronic applications.
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