M. Lo Faro

Oxygen-sensing properties of electrospun CNTs/PVAc/TiO2 composites

Multi-walled-carbon-nanotubes/polyvinylacetate/titanium oxide (MWCNTs/PVAc/TiO2) composite fibers with different MWCNT loadings were prepared using the electrospinning technique. The addition of cetyl trimethyl ammonium bromide (CTAB) as a surfactant agent to promote the dispersion of the MWCNTs was also evaluated. The morphological and microstructural properties of as-spun and annealed samples in air at 600°C were examined using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The sensing characteristics of the synthesized TiO2-based nanostructures were evaluated for oxygen monitoring at moderate temperatures. The effects of the MWCNT loading, the addition of the surfactant and the composition of the TiO2 crystalline phases were investigated and discussed.

Polyaniline nanofibers: Towards pure electrospun PANI

Nanofibers of conducting polymers, as polyaniline (PANI), have received a great deal of attention by the scientific community for their potential applications (electronic, magnetic, biomedical, optical fields). Recently the electrospinning has emerged as a promising technique to produce wires and fibers of polymers with diameters ranging from 10 nm to 10μm. PANI has poor processability by electrospinning due to its poor solubility in common solvents, but it is possible to spun polyaniline nanofibers adding another polymer to the organic solutions. The presence of an insulator copolymer decreases the fibers/wires conductivity. In this work we report the preparation of highly pure polyaniline fibers by electrospinning process. PANI powder has been characterized by FT-IR, UV-VIS, and X-Ray diffraction. The spun sample obtained have been characterized by SEM to evaluate the wire morphology and complex impedance spectroscopy (EIS) in order to measure the electrical conductivity. We observed that, reducing the amount of PEO in the PANI/PEO blend organic solution, the fiber sizes decreased from 421nm for higher content of PEO (PANI: PEO= 1: 1, w/w) to 230 nm (PANI: PEO= 1: 0.1, w/w). The way to collect the fiber has been also investigated. Using a rotanting collector we observed a stretching effect on the fibers which promotes a narrow distribution of fibers dimension with respect to the fibers obtained with static collector.Nanofibers of conducting polymers, as polyaniline (PANI), have received a great deal of attention by the scientific community for their potential applications (electronic, magnetic, biomedical, optical fields). Recently the electrospinning has emerged as a promising technique to produce wires and fibers of polymers with diameters ranging from 10 nm to 10μm. PANI has poor processability by electrospinning due to its poor solubility in common solvents, but it is possible to spun polyaniline nanofibers adding another polymer to the organic solutions. The presence of an insulator copolymer decreases the fibers/wires conductivity. In this work we report the preparation of highly pure polyaniline fibers by electrospinning process. PANI powder has been characterized by FT-IR, UV-VIS, and X-Ray diffraction. The spun sample obtained have been characterized by SEM to evaluate the wire morphology and complex impedance spectroscopy (EIS) in order to measure the electrical conductivity. We observed that, reducing t...

Electrospinning fabrication of polyvinyl alcohol and polyvinyl pyrrolidone/Sm(NO3)3-Sm2O3 composites nanofibers:

Polyvinyl pyrrolidone and polyvinyl alcohol thickeners and Sm(NO3)3 have been directly processed by electrospinning method to obtain composite nanofibers. Scanning electron microscopy micrographs indicated that the surface of the prepared composite fibers was smooth. X-ray diffraction analysis revealed that the composite nanofibers were amorphous in structure. Sm2O3 nanoparticles and nanofibers were fabricated by calcination of the composite fibers.