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The electrospinning technique was used to prepare nanofibers samples consisting of three groups, each group has a different polystyrene concentration (12, 14, 16 wt.%). Multiwalled carbon nanotubes were added to each group with four ratios to yield four samples comprising (polystyrene/MWCNT) constituents. The UV-Visible test was carried out to know how uniformly nanofibers and Mutli-walled carbon nanotubes were distributed in the polymeric nanofibers and their effect on the final nanofiber's properties through the absorption peaks. The morphological test used "Field Emission Scanning Electron Microscope". The results showed that; MWCNTS has a dominant effect on prepared nanofibers in the (12 wt.% Polystyrene) group, and both (PS, MWCNT) have a shared effect, highest steady absorption curves, and uniformly scattered radiation at (14 wt.% PS) group, and random results at (16 wt.% PS) group. From FESEM results we notice that increasing polymer concentration causes an increase in the nanofiber's diameter and beads formation chance increases at (12,16 wt.% PS) groups. In the group of (14 wt.% Polystyrene), it produces nanofibers with free beads and uniform distribution, the addition of MWCNT lowers the diameter of nanofibers much more and enhances the orientation, and improves their UV absorption, strength, and mechanical properties. [ABSTRACT FROM AUTHOR]

Carbon nanofibers (CNFs) with excellent conductivity and stability have become a promising material to design the strain sensing network. To date, however, the effect of the stacked structure of CNF membrane on the sensing performance has rarely been studied. In this work, we reported a high-performance sensor based on the cross-stacked aligned CNF membrane. The effects of cross-stacked structures on the sensing characteristics were systematically investigated. The flexible strain sensor could capture low detection limit (<0.1%) with a gauge factor (GF) of 4.24 and wide strain range up to 130%. The uniform GF value reached 2050 when the strain was in the range of 100–130%. In addition, the high linearity under 40% strain (>0.998), excellent durability and quick response time (<200 ms) were demonstrated. The excellent comprehensive performances were simultaneously obtained. The sensor could be used in extensive applications, such as monitoring body movements and distinguishing the track of writing. [ABSTRACT FROM AUTHOR]

In this study, conductive and transparent polycaprolactone (PCL)/carbon black (CB) nanofibers are produced by electrospinning. In order to investigate the effect of solvent system on the optoelectrical properties of PCL/CB nanofibers, the fibers are produced from two different solvent systems; namely, chloroform (CHL) and dimetyl formamid (DMF). For optoelectrical characterization, nanofibers are produced with different deposition times in the range of 1–10 minutes. Surface, optical, electrical and optoelectrical properties of the PCL/CB nanofibers are evaluated. Nanofibers produced from CHL solvent system results in non-uniform nanofibers with higher diameters. They also give a larger diameter distribution. On the other hand, nanofibers with uniform and smaller diameters are obtained from DMF system. UV-spectrophotometer analysis show that nanofiber mats produced from both solvent systems have similar optical transparencies. Lower sheet resistance values are obtained with the nanofiber mats produced from DMF system according to electrical characterizations. Higher Figure of Merit values are calculated for the nanofiber mats produced in DMF solvent system. Considering all the results, it can be concluded that PCL/CB nanofibers produced from DMF solvent system are better candidates compared to the nanofibers produced from CHL solvent system for optoelectrical applications. [ABSTRACT FROM AUTHOR]

In this study, a novel non-enzymatic glucose sensor was successfully produced using nickel electrodeposition on an oil free carbon nanofiber (CNF) mat prepared by electrospinning method. The as-prepared Ni/CNF mat electrode was studied by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The characterization results showed that not only was nickel coating electrodeposited on the CNF mat but also the nickel coating was uniformly deposited on the CNF mat electrode. The electrochemical properties of Ni/CNF mat were evaluated using cyclic voltammetry (CV) and amperometry measurements. It was found that the Ni/CNF mat electrode had good electrocatalytic activity toward the oxidation of glucose and demonstrated a wide linear range of 0.002–5 mM, a low detection limit of 0.57 µM, a rapid response time (2 s), a high selectivity with no interference from other oxidable species, good reproducibility and long-term stability. Moreover, the prepared sensor was used to identify glucose in real sample species. Therefore, Ni/CNF mat electrode due to good analytical performance, cost effective and simple preparation method can be proposed as a promising sensor for non-enzymatic glucose detection. [ABSTRACT FROM AUTHOR]

In the present work, a novel nanofiber-based filter has been presented which is comprised of composite nanofibers of polyamide-66 and TiO2 nanoparticles (PA-66/TiO2) for trapping cement dust. The produced nanofibers under optimum conditions were characterised by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The effect of some important electrospinning process parameters on the obtained electrospun nanofibers including solution concentration, flow rate, voltage‚ tip to collector distance and the presence of salt was investigated. Studies showed that the solution concentration of 15 wt. % of PA-66 resulted in thinner and smother nanofibers than the other solution concentrations and also the average diameter of the electrospun nanofibers was decreased with increasing 1 wt. % salt to the polymer solution. The produced nanofiber-based filter can be applied for capturing cement dust with a good filtration efficiency of 97% for 3–500 nm particles and a quality factor in the range of 0.069–0.034 Pa−1 [ABSTRACT FROM AUTHOR]

Antibacterial composite nanofibers have recently been widely applied in biomedical fields. The purpose of this study is to combine Polyamide66 (PA) with carbon nanotubes (CNTs) and Ag nanoparticles through electrospinning and the aqueous reduction method to synthesis Ag@CNT/PA composite nanofibers with excellent conductivity, antibacterial property and cytocompatibility. The morphology and structure of Ag@CNT/PA composite nanofibers were analyzed by a series of characterizations. Conductivity of Ag@CNT/PA composite nanofibers in wet state was measured using a four-probe resistance tester. The antibacterial activity of Ag@CNT/PA composite nanofibers was tested by inhibition zone method, and the MG-63 cells were used to detect the cytotoxicological effects of the composite nanofibers. The results show that the Ag nanoparticles (50–100 nm) are distributed uniformly on the surface of nanofibers. Conductivity of Ag@CNT/PA composite nanofibers reaches (9.918 ± 0.043) × 10−4 S mm−1, significantly higher than that of PA nanofibers ((1.486 ± 0.017) × 10−4 S mm−1). The Ag@CNT/PA composite fibers present good antibacterial activity against Escherichia coli and Staphylococcus aureus. Cell culture results show that the cell proliferation of Ag@CNT/PA composite nanofiber group seems no significant difference with PA nanofiber group (p > 0.05) at day 7. The Ag@CNT/PA composite nanofibers have no significant negative effects on MG-63 cells. [ABSTRACT FROM AUTHOR]

Copper oxide (CuO) nanofibers were successfully prepared by electrospinning and subsequent heat treatment. The chemical composition and morphology of the fibers were characterized by SEM, XRD and EDS. Beaded nanofibers with 100nm in diameter were prepared by simple electrospinning and calcining. The catalytic effect of CuO nanofibers on the combustion of ammonium perchlorate (AP) was investigated by TG and DTA. The results showed that the decomposition temperature of AP shifted by 101.9 °C to the low temperature and the catalytic efficiency was very high. This is mainly attributed to the higher surface to volume ratio of beaded copper oxide nanofibers compared with smooth nanofibers and spherical nanoparticles. The results suggest that the electrospinning of CuO nanofibers is a promising one-dimensional nanometer material in the field of propellant catalysis. [ABSTRACT FROM AUTHOR]

Construction of transition metal oxides-based carbonaceous nanostructures has been regarded as one of the most effective strategies to prepare the electrodes for high-performance supercapacitors. In this work, NiCo2O4 embedded carbon nanofibers (NiCo2O4-CNFs) are synthesized by the combination of one-step electrospinning and following thermal treatment. The obtained NiCo2O4-CNFs are evaluated as electrodes for supercapacitors. The testing results indicate that the NiCo2O4-CNFs present high specific capacitance of 836 F g−1 (vs. 38.02 F g−1 for carbon nanofibers (CNFs)) at 5 A g−1, and outstanding cycling ability with 80.9% retention after 2000 cycle times. Such excellent performances benefit from the integration of electric double layer capacitors and pseudocapacitors. This kind of NiCo2O4-embedded carbon nanofibers can serve as a promising candidate for electrode materials for supercapacitors. [ABSTRACT FROM AUTHOR]

Iron oxide particle-decorated lignin-based carbon nanofibers (IO-LCNFs) were fabricated from organic mixtures containing acetic acid lignin (AAL) together with ferric acetylacetonate (Fe(acac)3) via electrospinning followed by stabilization in air and carbonization in nitrogen. After the addition of Fe(acac)3, IO-LCNFs showed different morphologies: Non-fused IO-LCNFs were obtained with diameters of 400–500 nm; iron oxide nanoparticles with diameters of 30–60 nm were exposed outside and well-distributed when sufficient amounts of Fe(acac)3were added. These carbon nanofibers were then used as electrode material for pseudocapacitor. It was found that the iron oxide particles enhanced the resulting electrochemical properties via reversible redox reactions. IO-LCNFs made from the composite nanofibers with mass ratio of AAL/Fe(acac)3of 80/20 [i.e., IO-LCNFs (80/20)] exhibited the highest specific capacitance, 72.1 F g−1, at current density of 500 mA g−1. [ABSTRACT FROM PUBLISHER]

The nanomaterial is very popular in recent years. In this article, a new hybrid system by nickel oxide-modified Ag NPs/CNFs has been successfully produced by combining the electrospinning technique and calcination. Different proportions of nickel nitrate were mixed into the solution and the influence on the morphological structure of Ag nanoparticles was investigated, and then composite nanofibers were investigated, which indicated that Ag nanoparticles and NiO nanoparticles were uniform in size and dispersed homogeneously in the carbon nanofibers by different characterizations. [ABSTRACT FROM AUTHOR]

Activated carbon nanofibers (CNFs) were derived from electrospun nanofibers with subsequent heat treatment. They were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The applicability of activated CNFs for preconcentration and determination of organophosphorus pesticides (OPPs) was investigated by high-performance liquid chromatography with diode array detector (HPLC-DAD). Some important parameters influencing the extraction efficiency, such as amount of sorbent, pH, flow rate and amount of salt, were investigated by response surface method (RSM). The obtained results showed that this analytical method will be useful for the analysis of OPPs in tap water with high precision and accuracy. [ABSTRACT FROM AUTHOR]

A simple method to prepare the Ag porous carbon nanofiber is reported. Ag porous carbon nanofiber was prepared by electrospinning and high temperature calcination. In this process, AgNO3-PMMA/PAN solution was the precursor solution of electrospinning, and Ag nanoparticles and pores were made by high temperature calcination. The catalytic activity of the Ag porous carbon nanofibers was confirmed by the styrene epoxidation. In the catalytic process, the conversation of styrene was 71% and the selectivity of styrene oxide was 83%. [ABSTRACT FROM AUTHOR]

Electrospun polyacrylonitrile (PAN) nanofibers were pre-oxidized under 1, 2, and 3 wt% of KMnO4aqueous solutions. Scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction and Raman spectroscopy were used to study the effect of KMnO4concentration on the structures and properties of PAN-based heat stabilized and carbonized electrospun nanofiber mats. In FT-IR spectra of the preoxidized samples a new peak at 2340 cm−1designated to MnO4–C=N conjugation was revealed. Chemical modification by KMnO4was used to decrease the average diameter, increase the Bragg spacing, and decrease the preferred orientation and the crystal size. According to the Raman spectra, the bandwidths of the G mode became wider in the cases of preoxidized samples, while the G mode intensities belonging to the crystalline regions were decreased. According to the TGA studies, the weight losses in the preoxidized samples were severe due to the permanganate attack. [ABSTRACT FROM PUBLISHER]

Electrospun carbon nanofibers (ECNFs) have many qualities that make them attractive for applications in various fields of technology. For many applications, it is necessary to modify the surface of CNFs by chemical functionalization. Here, a systematic functionalization of polyacrylonitrile (PAN)-based ECNFs by oxidation in concentrated nitric acid was examined. The effects of oxidation on the microstructural, electrical, and mechanical characteristics have been studied. The Fourier transform infrared spectroscopy results revealed the time-dependent functionalization of ECNFs. However, according to the scanning electron microscopy, there was no considerable change in the surface morphology of CNFs due to functionalization. The microstructures as well as electrical and mechanical properties were severely dependent on oxidation duration according to X-ray diffraction and Raman spectroscopies as well as conductivity and mechanical strength measurements, respectively. Increase in oxidation duration led to more structural disorders and noticeable decrease in electrical conductivity and mechanical strength. [ABSTRACT FROM AUTHOR]

In this work, three different methods of preparation of polyacrylonitrille (PAN) with carbon black (CB) solutions further used in electrospinning for producing conductive fiber mats are discussed. CB is used as conductive filler. Content of CB in polymer matrix is varied, CB/PAN = 1/2, 1/1, and 3/2. The solution properties and obtained fiber morphology are analyzed. The effect of preparation on fiber morphology and conductivity is analyzed, as well as the effect of sonication on solution properties, morphology, and conductivity of PAN+CB samples. [ABSTRACT FROM PUBLISHER]