Poly（vinyl pyrrolidone）（PVP）/Fe 3O 4 composite nanofibers were successfully prepared by using electrospinning technique.The composite nanofibers were characterized by means of TEM（transmission electron microscopy...Poly（vinyl pyrrolidone）（PVP）/Fe 3O 4 composite nanofibers were successfully prepared by using electrospinning technique.The composite nanofibers were characterized by means of TEM（transmission electron microscopy）,XRD（X-ray diffraction）and TGA（thermogravimetric analysis）.Transmission electron microscope images of the PVP/Fe3O4 nanofibers show that the Fe3O4 nanoparticles with a diameter about 10.5 nm were dispersed in PVP fiber matrices.The XRD results show that the particles in PVP fibers were indeed Fe3O4 nanoparticles.And the TGA of PVP/Fe3O4 nanofibers show that the content of Fe3O4 nanoparticles in the composite was about 36.8%（mass fraction）.The PVP/Fe3O4 nanofibers were found to be superparamagnetic.The hysteresis loop at room temperature showed a high saturated magnetization（M s=15.1 emu/g）and a low coercive force（μ c=0）.展开更多
A new photochromic complex of Keggin type tungstophosphate acid/polyvinyl pyrrolidone system was prepared, and its thin films was made by the dipping method. Their photochromic properties were investigated by FTIR, UV...A new photochromic complex of Keggin type tungstophosphate acid/polyvinyl pyrrolidone system was prepared, and its thin films was made by the dipping method. Their photochromic properties were investigated by FTIR, UV Vis spectra. The salts were formed by the combination of the ion based on the N atoms in the polymeric molecules and H + of the acids. The UV Vis spectra showed that this type of system had an excellent photochromic behavior. The g values of ESR spectra for the one electron blues were the characteristic of tetragonal W(Ⅴ) complex in colored thin film. It was indicated that the charge could be transferred between the anion and cation under irradiation of UV light and the result in the oxidation of the cation and the reduction of the anion.展开更多
文摘Poly（vinyl pyrrolidone）（PVP）/Fe 3O 4 composite nanofibers were successfully prepared by using electrospinning technique.The composite nanofibers were characterized by means of TEM（transmission electron microscopy）,XRD（X-ray diffraction）and TGA（thermogravimetric analysis）.Transmission electron microscope images of the PVP/Fe3O4 nanofibers show that the Fe3O4 nanoparticles with a diameter about 10.5 nm were dispersed in PVP fiber matrices.The XRD results show that the particles in PVP fibers were indeed Fe3O4 nanoparticles.And the TGA of PVP/Fe3O4 nanofibers show that the content of Fe3O4 nanoparticles in the composite was about 36.8%（mass fraction）.The PVP/Fe3O4 nanofibers were found to be superparamagnetic.The hysteresis loop at room temperature showed a high saturated magnetization（M s=15.1 emu/g）and a low coercive force（μ c=0）.
文摘A new photochromic complex of Keggin type tungstophosphate acid/polyvinyl pyrrolidone system was prepared, and its thin films was made by the dipping method. Their photochromic properties were investigated by FTIR, UV Vis spectra. The salts were formed by the combination of the ion based on the N atoms in the polymeric molecules and H + of the acids. The UV Vis spectra showed that this type of system had an excellent photochromic behavior. The g values of ESR spectra for the one electron blues were the characteristic of tetragonal W(Ⅴ) complex in colored thin film. It was indicated that the charge could be transferred between the anion and cation under irradiation of UV light and the result in the oxidation of the cation and the reduction of the anion.
