Tesis
Study of Nanofibers Formed by Magnetic Field Assisted Electrospinning Using Solutions Containing PVDF, DMF, Acetone and Fe3O4 Nanoparticles
Autor
González Sánchez, Juan A.
Furlan, Rogerio (Consejero)
Institución
Resumen
We present a comprehensive study on Polyvinylidene Fluoride (PVDF) nanofibers with solutions containing Fe3O4 nanoparticles (NPs). These fibers were formed by using an in house designed Magnetic Field Assisted Electrospinning (MFAES) setup. They were deposited on silicon (Si) substrates positioned in a rotating collector using a speed controlled electrical motor, in order to obtain certain degree of orientation. Fourier Transform Infrared (FTIR) spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Raman Spectroscopy, Ferromagnetic Vibration Sampler Magnetometry (VSM), Viscosimetry, Precision LC Analyzer (PLCA) and Atomic Force Microscopy (AFM) were employed to evaluate the crystalline quality, the morphology and the ferroelectric and magnetic properties of the resulting nanofibers.
FTIR and XRD show that the PVDF powder used is this experiments is absent of intrinsic piezoelectricity, but this property was observed in all nanofibers obtained after electrospinning. This results demonstrate that the electric field used in the MFAES had an influence in the crystalline structure of the fibers, being responsible for the formation of the b- phase, which is associated with piezoelectricity.
The addition of Fe3O4 NPs allowed to obtain nanofibers with ferromagnetic hysteresis with a magnetization around 2000 gauss. It was possible to combine unique properties of each materials by joining the piezoelectricity of the PVDF with the ferromagnetism of the Fe3O4. A motion response of the nanofibers was observed with nanoparticles with the application of high magnetic fields. Raman analysis shows that the addition of nanoparticles affects the Carbon-Hydrogen peaks indicating the formation of strong hydrogen bridges between the surface of Fe3O4 and the PVDF. It appears that the nanoparticles do not react with the PVDF, but Raman results shows a weak bond between molecules.