Diameter Of Composite Nanofibers Research Articles

Effect of multi wall carbon nanotubes on characteristics and morphology of nanofiber scaffolds composited of MWNTs/silk fibroin

Composite of multi wall carbon nanotubes (MWNTs) and silk fibroin were electrospun to nanofiber scaffolds with average diameter ranged from 46.2 to 100nm. The effect of increasing the percentage of the MWNTs was evaluated on properties, characterizes and morphology of composite nanofiber scaffolds. Solution concentration, electric field, distance of needle from collector and flow rate were optimized for electrospinning. Optical and scanning electron microscope were used to study the morphology and diameter of composite nanofibers. The properties and characterizes were considered by using the FTIR spectroscopy, X-ray and Raman spectroscopy in addition, the electrical conductivity was measured utilizing Four-Point Probe method. Results showed that augmentation of the MWNTs had a small effect on the nanofiber surface. A growth was seen in the composite nanofiber diameter by increasing the MWNTs. Chemical interaction was not happened between MWNTs and silk fibroin based on FTIR spectroscopy and X-ray analysis also, crystallization of composite nanofibers grew by adding MWNTs. Raman spectroscopy proved that MWNTs were incorporated in the silk fibers. The electrical conductivity of composite nanofiber scaffolds was increased by increment of the MWNTs.

Dy3+ and Eu3+ Co-doped NaGdF4 nanofibers endowed with bifunctionality of tunable multicolor luminescence and paramagnetic properties

Luminescent-magnetic bifunctional NaGdF4:Dy3+,Eu3+ nanofibers have been successfully fabricated via the combination of electrospinning followed by calcination with fluorination technique for the first time. The structure, morphologies, luminescence, and magnetic properties of the synthesized nanofibers have been characterized by a variety of techniques. X-ray diffraction (XRD) analysis shows that as-prepared NaGdF4:Dy3+,Eu3+ nanofibers are pure hexagonal structure. Scanning electron microscope (SEM) observations indicate that directly electrospinning-made PVP/[NaNO3+Gd(NO3)3+Dy(NO3)3+Eu(NO3)3] composite nanofibers have smooth surfaces, good dispersion and uniform size, and the surfaces of NaGdF4:Dy3+,Eu3+ nanofibers become rough after calcination and fluorination process. The diameters of composite nanofibers and NaGdF4:Dy3+,Eu3+ nanofibers are respectively 400.19±48.06nm and 245.90±52.10nm. NaGdF4:Dy3+,Eu3+ nanofibers exhibit predominant visible emission under 274nm ultraviolet light excitation and the trend of their color tones changes from blue, cold white, warm white to red by adjusting the molar concentration of Eu3+. In addition, all of the samples exhibit paramagnetic features and the magnetic properties of NaGdF4:Dy3+,Eu3+ nanofibers are tunable by changing the species and doping concentration of RE3+ ions. More importantly, the tunable multicolor luminescence and paramagnetic properties are simultaneously realized in single-phase NaGdF4:Dy3+,Eu3+ nanofibers, which ideally suit to apply in many fields such as solid-state lasers, lighting and displays, magnetic resonance imaging. This design conception and construction strategy developed in this work may provide some new guidance for the synthesis of other rare earth fluorides nanostructures with various morphologies.

Preparation, morphology and conductivity of polyacrylonitrile/multi-wall carbon nanotubes composite nanofibers

Composite nanofibers of polyacrylonitrile/multi-wall carbon nanotubes (PAN/MWCNTs) were prepared via electrospinning. Samples contained 0, 0.5, 1, 2, 3, and 3.5 wt% of MWCNTs. The viscosity and electrical conductivity of electrospinning solutions were measured. Results revealed that, with the addition of multi-wall carbon nanotubes, viscosity was increased and electrical conductivity was improved. Rheological behavior was studied using two different viscometers. Moreover, morphology and diameters of the composite nanofibers were studied by scanning electron microscopy (SEM) and nanofiber diameter distributions were presented. SEM micrographs showed that by adding MWCNTs, the average diameter of nanofibers was increased. Furthermore, the effect of MWCNTs on glass transition temperature, T g, was investigated using differential scanning calorimetry (DSC) technique. The results showed that T g was increased with the addition of MWCNTs. In addition, Fourier transform infrared spectroscopy (FTIR) results showed that MWCNTs can affect the orientation ability of polymer chains. The effects of adding salt, increasing voltage and changing the tip-to-collector distance on the morphology and diameters of composite nanofibers were examined. The electrical conductivity results of electrospun mats were measured by a two-probe method. Electrical conductivity was increased by addition of MWCNTs and its behavior followed the percolation theory. Finally, it was observed that mats with smaller diameters have higher electrical conductivity.

Effect of FeCl3 on the morphology, wetting behavior, and stabilization/carbonization of polyacrylonitrile nanofibers prepared by electrospinning

AbstractHerein we report that the neat polyacrylonitrile (PAN) nanofibers and PAN/FeCl3 composite nanofibers were prepared by the materials-processing technique of electrospinning. The effect of FeCl3 amount on the morphology and wetting behavior of the resulting composite nanofibers were studied by scanning electron microscopy (SEM) and drop shape analysis (DSA), respectively. The SEM images indicated that the diameters of composite nanofibers decreased with increase of FeCl3 amount, and this was probably due to the conductivity increase of spinning solutions. The results acquired from DSA measurement showed that the addition of FeCl3 increased the surface contact angle of water deposited on composite nanofibers, suggesting the higher hydrophobicity and the lower wetting behavior. Additionally, the effect of FeCl3 on stabilization and carbonization of the PAN composite nanofibers were investigated. The structural and morphological evolutions of the stabilized and carbonized nanofibers were studied by Fourier transfer infrared (FTIR) spectra and SEM. The FTIR spectra showed that the presence of FeCl3 in composite nanofibers considerably varied the mechanisms of thermo-chemical reactions during the heat treatments. The SEM images revealed that there were conglutinations of nanofibers after carbonization, while the degree of conglutination for the carbonized PAN composite nanofibers with FeCl3 was higher than that for the carbonized neat PAN nanofibers.

Nanoscale three-point bending of single polymer/inorganic composite nanofiber

The pure polyvinyl acetate (PVAc) nanofiber and PVAc/titanium dioxide (TiO2) composite nanofiber were prepared by sol–gel process with electrospinning. The effect of increasing TiO2 contents on diameter distribution, surface morphology, and elastic modulus of nanofibers was characterized using a scanning electron microscope (SEM) and an atomic force microscope (AFM) equipped with picoforce. SEM images showed that the average diameter of composite nanofiber decreased with the increase in TiO2. The three‐point bending test indicated that the elastic modulus of PVAc/TiO2 nanofiber significantly increased as TiO2 increased.

Highly Uniform Self-Assembled Conducting Polymer/Gold Fibrous Nanocomposites: Additive-Free Controllable Synthesis and Application as Efficient Recyclable Catalysts

Uniform poly(2-aminothiophenol) nanofibers embedded with highly dispersed gold nanoparticles have been fabricated through a facile templateless one-step method. The diameter of composite nanofibers can be controlled in the range of 200-80 nm by simply tuning the speed of mechanical stirring during materials synthesis. Results from our work will provide insight into the shape-controlled synthesis of other nanomaterials by simply introducing mechanical agitation. Removal of gold nanoparticles in composite nanofibers leads to polymer nanotubes with continuous or incontinuous nanocavities depending on mechanical stirring speeds. Furthermore, morphology-dependent catalytic performances of such composites are also investigated.

Effects of ferric chloride on structure, surface morphology and combustion property of electrospun polyacrylonitrile composite nanofibers

In this work, the pure polyacrylonitrile (PAN) nanofibers and PAN/FeCl3 composite nanofibers were prepared by an electrospinning process. Electrospinning solution properties including viscosity, surface tension and conductivity, had been measured and combined with the results of Scanning electron microscopy (SEM), Atomic force microscope (AFM) and Micro Combustion Calorimeter (MCC) to investigate the effects of FeCl3 on the structure, surface morphology and combustion property of electrospun PAN nanofibers, respectively. It was found from SEM images that the diameters of composite nanofibers were decreased with the addition of FeCl3, which was attributed predominantly to the increased conductivity of the polymer solutions compared to viscosity and surface tension. The AFM analyses revealed that the surface morphology of electrospun nanofibers changed from smooth and wrinkle-like structure (without FeCl3) to rough and ridge-like structure (with FeCl3). The results characterized by MCC showed that the loading of FeCl3 decreased the heat release rate (HRR) and improved the combustion property of composite nanofibers.

Structure and Morphological Evolvement of Electrospun Polyacrylonitrile/Organic–Modified Fe-Montmorillonite Composite Carbon Nanofibers

In the present work, a facile compounding and electrospinning method was used to prepare PAN/Fe-OMT composite nanofibers. Electrospinning solution properties including viscosity, surface tension, and conductivity were measured and combined with the results of Fourier transform-infrared (FT-IR) spectra, high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM) to investigate the effects of Fe-OMT on the structure and morphology of electrospun PAN nanofibers, respectively. It was found from FT-IR and HRTEM that the silicate clay layers were well dispersed within the composite nanofibers and were oriented along the fiber axis. The SEM images indicated that the loading of Fe-OMT decreased the average diameters of composite nanofibers due to the increased conductivity of composite solutions. Then, the prepared PAN nanofibers and PAN/Fe-OMT composite nanofibers were further pre-oxidized and carbonized. The effects of Fe-OMT on the structure and morphology of PAN-based carbon nanofibers were also investigated by FT-IR and SEM. The FT-IR spectra indicated that there were different characteristic absorption peaks for pure PAN nanofibers and PAN/Fe-OMT composite nanofibers during the pre-oxidation and carbonization processes. The SEM images revealed that the morphology of nanofibers underwent marked changes before and after carbonization. The Fe-OMT loadings might promote the dehydrogenation, cyclization, and cross-linking reactions of the PAN composite nanofibers during carbonization.

Electrospun Poly(L‐Lactide‐co‐ε‐Caprolactone)/Polyethylene Oxide/Hydroxyapaite Nanofibrous Membrane for Guided Bone Regeneration

A series of poly(L‐lactide‐co‐ε‐caprolactone)/polyethylene oxide/hydroxyapaite (PLCL/PEO/HA) composite fibrous membranes were prepared by elecrospinning technology for guided bone regeneration. The morphology, water permeability and mechanical properties of the membranes were investigated. The HA nanocrystals can be well distributed in the PLCL/PEO matrix. And the diameter of composite nanofiber is larger than that of pure PLCL. The fibers with uniform size and large diameter were obtained when the contents of PEO and HA were 0.4% and 0.03%, respectively. In this condition, the obtained membrane presents the best water permeability. Furthermore, the nanofibrous membrane with largest tensile strength was obtained when the contents of PEO and HA were 0.5% and 0.03%, respectively.