Search

Present work introduces the fabrication of antibacterial nanofibers composite of poly(vinyl acetate) doped with in situ-synthesized rice grain-shaped ZnS nanoparticles using electrospinning technique. FE-SEM and TEM analyses revealed that the ZnS nanoparticles were uniformly incorporated inside the polymer nanofibers. The antibacterial activity of as-fabricated nanofibers composite was investigated under indoor light activation towards Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. Such strategy for immobilizing ceramic nanoparticles inside polymer nanofibers might be helpful to overcome the photocorrosion and recovery problems of ZnS-based materials.

For the first time, heterostructures of electrospun carbon nanofibers decorated with Ag3PO4 nanoparticles (Ag3PO4/CNFs) were successfully fabricated by the combination of simple and versatile electrospinning technique followed by carbonization and incorporation of Ag3PO4 nanoparticles via colloidal and precipitation synthesis approaches. The as-fabricated heterostructures were characterized by FESEM with EDS, XRD, TEM with HRTEM, FTIR and UV-vis diffuse reflectance spectroscopy. Experimental results revealed that the heterostructure obtained by colloidal synthesis approach (Ag3PO4/CNFs-1) was decorated with small-sized (~20 nm) and uniformly distributed Ag3PO4 nanoparticles on the surface of CNFs without any evident agglomeration, while in the heterostructure obtained by the precipitation synthesis approach (Ag3PO4/CNFs-2), CNFs were decorated with agglomerated and bigger-sized Ag3PO4 nanoparticles. The visible-light-driven photocatalytic investigation signified that the Ag3PO4/CNFs-1 heterostructure can exhibit higher performance towards the photodegradation of MB dye solution compared to the Ag3PO4/CNFs-2 heterostructure, which could be attributed to the synergistic effect between the uniformity and small size of Ag3PO4 nanoparticles and CNFs that can serve as a conductivity network to prevent the recombination of charge carriers. Moreover, the mechanism of the photocatalytic activity as-prepared heterostructure is proposed.

Mercuric (Hg

Mercuric (Hg2+) ions released from human activities, natural phenomena, and industrial sources are regarded as the global pollutant of world’s water. Hg2+ ions contaminated water has several adverse effects on human health and the environment even at low concentrations. Therefore, rapid and cost-effective method is urgently required for the detection of Hg2+ ions in water. Although, the current analytical methods applied for the detection of Hg2+ ions provide low detection limit, they are time consuming, require expensive equipment, and are not suitable for in-situ analysis. Metal nanoclusters (MNCs) consisting of several to ten metal atoms are important transition missing between single atoms and plasmonic metal nanoparticles. In addition, sub-nanometer sized MNCs possess unique electronic structures and the subsequent unusual optical, physical, and chemical properties. Because of these novel properties, MNCs as a promising material have attracted considerable attention for the construction of selective and sensitive sensors to monitor water quality. Hence this review is focused on recent advances on synthesis strategies, and optical and chemical properties of various MNCs including their applications to develop optical assay for Hg2+ ions in aqueous solutions.

Present work reports the enhancement in photocatalytic performance of Ag3PO4 nanoparticles through sulfate doping and anchoring on Polyacrylonitrile (PAN)-electrospun nanofibers (SO42&minus, Ag3PO4/PAN-electrospun nanofibers) via electrospinning followed by ion-exchange reaction. Morphology, structure, chemical composition, and optical properties of the prepared sample were characterized using XRD, FESEM, FTIR, XPS, and DRS. The anchoring of SO42&minus, Ag3PO4 nanoparticles on the surface of PAN-electrospun nanofibers was evidenced by the change in color of the PAN nanofibers mat from white to yellow after ion-exchange reaction. FESEM analysis revealed the existence of numerous SO42&minus, Ag3PO4 nanoparticles on the surface of PAN nanofibers. Photocatalytic activity and stability of the prepared sample was tested for the degradation of Methylene blue (MB) and Rhodamine B (RhB) dyes under visible light irradiation for three continuous cycles. Experimental results showed enhanced photodegradation activity of SO42&minus, Ag3PO4/PAN-electrospun nanofibers compared to that of sulfate undoped sample (Ag3PO4/PAN-electrospun nanofibers). Doping of SO42&minus, into Ag3PO4 crystal lattice could increase the photogenerated electron&ndash, hole separation capability, and PAN nanofibers served as support for nanoparticles to prevent from agglomeration.

Present study reports the synthesis of Ag3PO4 nano/mircoparticles by facile precipitation and colloidal synthesis approach in aqueous solution. Importantly, the presented approach does not require complicated instruments, difficult processes, and harsh conditions such as high temperature and high pressure. The obtained samples were characterized using SEM with EDS, XRD, TEM with HR-TEM and SAED, and FTIR. Their optical properties were studied using UV–vis diffusive reflectance spectra. Size dependent antibacterial activity towards Gram-positive (S. aureus) and Gram-negative (E. coli, K. pneumoniae and P. aeruginosa) bacteria. Experimental results showed that the antibacterial performances of nanoparticles obtained by mixing 0.01 M of each reactant (colloidal synthesis approach) were found to be much higher than that of other formulation under identical conditions.

Titanium dioxide nanoparticles using lysozyme (L:TiO2) were prepared through a facile synthesis. Structural, morphological and optical properties of L: TiO2 were compared with synthesized TiO2 nanoparticles prepared without lysozyme. X-Ray Diffraction (XRD) patterns showed dominance of anatase phase in L:TiO2 whereas rutile phase in TiO2. Their grain size was reduced from 38 to 17 nm on using lysozyme. Fourier Transform Infra Red (FTIR) study revealed the existence of chemical bonding of Titanium and Oxygen in both phases. The band gap energy was decreased from 3.3 to 3.1 eV on employing lysozyme. L:TiO2 nanoparticles showed better performance than TiO2 in photocatalytic degradation of Methylene Blue (MB) and Methyl Orange (MO) under ultraviolet irradiation.

In the present study, Ag nanoparticles decorated Mn2O3 hybrid nanofibers were fabricated by calcination of electrospun PVP/AgNO3/Mn(NO3)2 precursor nanofibers and characterized by FESEM, EDS, XRD, TEM. It was found that the prepared hybrid nanofibers included tiny Ag nanoparticles (from several to 15 nm) distributed uniformly in the Mn2O3 matrix. The investigation of bactericidal activity towards gram-positive and gram-negative bacteria showed that Ag/Mn2O3 hybrid nanofibers could exhibit enhanced efficiency than that of bare Mn2O3 nanofibers. Therefore, this result suggests that the as prepared Ag/Mn2O3 hybrid nanofibers can be a promising nanomaterial as a good alternative for the development of new bactericides.

Ag 3 PO 4 /PAN composite nanofibers have been fabricated by simple and low cost electrospinning technique followed by surface modification of PAN nanofibers with amidoxime ( C(CN 2 ) NOH) groups to utilize as anchoring sites for Ag + ions through coordinate bonding. Subsequently, the coordinated Ag + ions were allowed to react with PO 4 3− ions in order to form Ag 3 PO 4 /PAN composite nanofibers. Thus obtained composites were characterized by FESEM, XRD, TEM, FTIR, XPS and UV–vis. Experimental results revealed that composite nanofibers prepared by reacting ( C(CN 2 ) NOH) functionalized PAN nanofibers with 0.02 M solutions of AgNO 3 and Na 2 HPO 4 have higher efficiency towards the photodegradation and bactericidal activities under visible light.

In this work, flexible ternary composites of cobalt-doped cadmium selenide/electrospun carbon nanofibers (Co-CdSe@ECNFs) for photocatalytic applications were fabricated successfully via electrospinning, followed by carbonization. For the fabrication of the proposed photocatalysts, Co-CdSe nanoparticles were grown in situ on the surface of ECNFs during the carbonization of precursor electrospun nanofibers obtained by dispersing Se powder in the electrospinning solution of polyacrylonitrile/N,N-Dimethylformamide (PAN/DMF) containing Cd2+ and Co2+. The photocatalytic performance of synthesized samples is investigated in the photodegradation of methylene blue (MB) and rhodamine B (RhB) dyes. Experimental results revealed the superior photocatalytic efficiency of Co-CdSe@ECNFs over undoped samples (CdSe@ECNFs) due to the doping effect of cobalt, which is able to capture the photogenerated electrons to prevent electron&ndash, hole recombination, thereby improving photocatalytic performance. Moreover, ECNFs could play an important role in enhancing electron transfer and optical absorption of the photocatalyst. This type of fabrication strategy may be a new avenue for the synthesis of other ECNF-based ternary composites.

Heterojunction nanofibers of PAN decorated with sulfate doped Ag3PO4 nanoparticles (SO42&minus, Ag3PO4/PAN electrospun nanofibers) were successfully fabricated by combining simple and versatile electrospinning technique with ion exchange reaction. The novel material possessing good flexibility could exhibit superior antibacterial property over sulfate undoped species (Ag3PO4/PAN electrospun nanofibers). FESEM, XRD, FTIR, XPS and DRS were applied to characterize the morphology, phase structure, bonding configuration, elemental composition, and optical properties of the as fabricated samples. FESEM characterization confirmed the successful incorporation of SO42&minus, Ag3PO4 nanoparticles on PAN electrospun nanofibers. The doping of SO42&minus, ions into Ag3PO4 crystal lattice by replacing PO43&minus, ions can provide sufficient electron-hole separation capability to the SO42&minus, Ag3PO4/PAN heterojunction to generate reactive oxygen species (ROS) under visible light irradiation and enhances its antibacterial performance. Finally, we hope this work may offer a new paradigm to design and fabricate other types of flexible self-supporting negative-ions-doped heterojunction nanofibers using electrospinning technique for bactericidal applications.

Highly photocatalytic and antibacterial Ag2CO3 nanoparticles were incorporated into PAN nanofibers by electrospinning technique followed by ion exchange reaction between silver nitrate and sodium bicarbonate at room temperature. The samples were characterized by field-emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), photoluminescence (PL), and Fourier transformed infrared (FT-IR) spectroscopy. The as prepared sample was found to exhibit an excellent photocatalytic activity toward degradation of methylene blue (MB) in aqueous solution and antibacterial properties against Escherichia coli (E. coli) under visible light. The perfect recovery of catalyst after reaction and its unchanged efficiency for cyclic use showed that it will be an economically and environmentally friendly photocatalyst for the water purification.

First time, polyacrylonitrile (PAN)/Ag2CO3 composite nanofibers (NFs) with uniformly distributed Ag2CO3 nanoparticles (NPs) inside polyacrylonitrile NFs were fabricated via simple and versatile technique; electrospinning of colloidal solution of PAN and Ag2CO3 NPs. In this work, Ag2CO3 NPs were synthesized by ion-exchange method between Ag(NH3)2+ and NaHCO3. The experimental result demonstrated that PAN/Ag2CO3 composite NFs with average diameter of approximately 430 nm can exhibit good photocatalytic activity for the photodegradation of methyl red under visible light irradiation. In addition, thus obtained composite NFs displayed enhanced antibacterial activities toward both gram-positive and gram-negative bacteria due to its photogenerated electron–hole pairs indicating that this sort of material may represent a new, promising alternative with a wide range of potential application in the field of water treatment.

Use of nanostructured materials in powder form for various applications might show excellent performances, however they create serious problem due to separation difficulty, loss and photocorrosion during use, and their reusability in the case of large scale processes. This review presents the research that has been focused on the fabrication of composite NFs in which nanostructured materials are encapsulated in polymeric matrix by means of simple, effective, low cost, high yield technique; electrospinning in order to overcome the afore mentioned problems. Polymer NFs not only act as supporter but also prevent the aggregation and leaching of nanostructures improving their performances.

In this paper, we presented the fabrication of human hair derived keratin/poly(vinyl alcohol) composite nanofibers exhibiting high optical transmittance by using simple and versatile electrospinnig technique. Keratin was extracted from human hair by sulphitolysis process and glyoxal solution was used as crosslinking agent in the system. More interestingly, the high optical transmittance (∼88% at a wave length of 600 nm) of the composite was achieved by simply immersing it in water without adding any additive. Furthermore, the tensile strength and Young's Modulus of the transparent composite nanofibers were also found to be increased (19 and 272.8 MPa) as compared to the PVA nanofibers (10.7 and 72.4 MPa).

This paper presents fabrication of polyacrylonitrile (PAN) electrospun nanofibers (NFs) reinforced with Ag2CO3 nanoparticles (NPs) as highly efficient visible light photocatalyst. Preparation of the introduced NFs was accomplished by using simple, effective, high yield, and low cost process; electrospinning of Ag2CO3/PAN colloidal solution at different applied electric voltages. Photocatalytic efficiency of the introduced nanofiber mats was investigated by photodegradation of three dyes (Methyl orange, Methylene blue, and RhodamineB) under visible light irradiation. Experimental results indicated that the nanofiber mat obtained at applied electric voltage of 18 kV could show higher performance towards the photodegradation of organic contaminants. Moreover, field emission scanning electron microscopy (FE-SEM) and transmission electron microscope (TEM) analysis confirmed the confinement of Ag2CO3 NPs inside polymeric NFs, which can overcome the serious problems of photocorrosion of photocatalyst and secondary pollution. Overall, the introduced NFs can be used as efficient, low cost, and healthily safe visible light driven photocatalyst in the field of water treatment and can promote its industrial application, especially in the open water surfaces.

Heterogeneous photocatalysis involving zinc oxide (ZnO) nanofibers (NFs) has emerged as a new promising route for the cost-effective treatment of organic pollutants and the transformation of hazardous substances into benign forms. In general, it involves the development of smart approaches to reduce the harmful effects of highly toxic pollutants, which are difficult to treat. This review presents research that has been focused on the fabrication of electrospun ZnO hybrid NFs and their applications in the photodegradation of different organic pollutants that are discharged into wastewater from textile and other industrial processes. Furthermore, a short discussion on charge transfer mechanisms during photocatalytic reactions is also presented.

Effective PdS/ZnS NPs doped PVAc hybrid electrospun nanofiber mat is introduced as an efficient and reusable photocatalyst. The NPs were synthesized in situ by addition of (NH4)2S to PVAc/ZnAc/PdAc solution. Fabrication of good morphology nanofibers containing PdS/ZnS NPs was achieved by simple, effective, low cost and high yield technology; electrospinning of PVAc/PdS/ZnS colloid. Besides the effective photocatalytic activity, the introduced immobilization strategy of NPs is considered an acceptable methodology to solve the problems of secondary pollution of nanostructural photocatalyst. Overall, the introduced mat can be used as low cost, efficient, and reusable healthily safe photocatalyst to overcome the aforementioned problem.

In this study, a novel polyurethane (PU) nanofibrous mat doped with Ag-CoF NPs has been synthesized by electrospinning technique in which the in situ reduction of Ag+ into Ag NPs was achieved by utilizing the reduction ability of N,N-dimethylformamide (DMF), which played dual roles as a solvent and reducing agent. Typically, solgel consisting of CoF/PU and AgNO3 was stirred for 3 h and electrospun. The crystalline structure and uniform distribution of Ag-CoF NPs in/on PU NFs were demonstrated by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. Two organic dyes, MB and RhB, were used to investigate the photocatalytic activity of the nanofibrous mat under visible light irradiation.

Easy fabrication, porosity, good mechanical properties, and composition controllable of the electrospun nanofiber mat make this material a promising candidate for wound dressing applications. In the present study, nylon6/gelatin electrospun nanofiber mats are introduced as novel wound dressing materials. The introduced mats were synthesized by electrospinning of nylon6 and gelatin mixtures, three mats containing different gelatin content were prepared; 10, 20 and 30 wt%. Interestingly, addition of the gelatin did not affect the mechanical properties of the nylon 6, moreover the mat containing 10 wt% gelatin revealed higher mechanical properties due to formation of spider-net like structure from very thin nanofibers (∼10 nm diameter) bonding the main nanofibers. Biologically study indicates that gelatin incorporation strongly enhances the bioactivity performance as increasing the gelatin content linearly increases the MC3T3-E1 cell attachment. Overall, the obtained results recommend exploiting the introduced mats as wound dressing material.

Composite nanofibers consisting of Mn 2 O 3 and TiO 2 were prepared by the electrospinning process, and tested as Gram-class-independent antibacterial agent and photocatalyst for organic pollutants degradation. Initially, electrospinning of a sol–gel consisting of titanium isopropoxide, manganese acetate tetrahydrate and poly(vinyl pyrrolidone) was used to produce hybrid polymeric nanofibers. Calcination of the obtained nanofibers in air at 650 °C led to produce good morphology Mn 2 O 3 /TiO 2 nanofibers. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the as-spun nanofibers and the calcined product. X-ray powder diffractometry (XRD) analysis was also used to characterize the chemical composition and the crystallographic structure of the sintered nanofibers. The antibacterial activity of Mn 2 O 3 /TiO 2 nanofibers against Gram negative and Gram positive bacteria was investigated by calculating the minimum inhibitory concentration after treatment with the nanofibers. Investigations revealed that the lowest concentration of Mn 2 O 3 /TiO 2 nanofibers solution inhibiting the growth of Staphylococcus aureus ATCC 29231 and Escherichia coli ATCC 52922 strains is 0.4 and 0.8 μg/ml, respectively. Incorporation of Mn 2 O 3 significantly improved the photodegradation of methylene blue (MB) dye under the visible light irradiation due to enhancing rutile phase formation in the TiO 2 nanofibers matrix.

In this study, the effective cobalt sulfide NPs were successfully encapsulated inside polyacrylonitrile (PAN) electrospun nanofibers. Typically, the solid NPs were in-situ synthesized by addition of ammonium sulfide drops to PAN/cobalt acetate solution. Electrospinning of the obtained colloid led to obtain good morphology polymeric nanofibers containing CoS NPs. Complete sheathing of the active nanoparticles did not affect their catalytic activity as the prepared mats revealed high performance toward hydrogen release from ammonia borane hydrolysis. Moreover, as a photocatalyst, a mat containing 2 wt% CoS could catalyze oxidation of methylene blue dye to be completely eliminated within 15 min. Furthermore, the introduced nanofibers photocatalytically enhanced complete degradation of the methyl red dye within relatively short time. The experimental results indicated that the optimum CoS content is 2 wt%, more increase in the concentration of the solid NPs leads to particles aggregation and consequently decrease the surface area. Beside the good activity obtained, the introduced immobilization strategy is considered an acceptable methodology to overcome the secondary pollution of the nanostructural photocatalysts because of the easy separation feasibility.

Doping of the polymeric electrospun nanofibers by metal oxides nanoparticles is usually performed by electrospinning of a colloidal solution containing the metal oxide nanoparticles. Besides the economical aspects, electrospinning of colloids is not efficient compared with spinning of sol–gels, moreover well attachment of the solid nanoparticles is not guaranteed. In this study, reduction of zinc acetate could be performed inside the nylon-6 electrospun nanofibers; so polymeric nanofibers embedding ZnO nanoflakes were obtained. Typically, zinc acetate/nylon-6 electrospun nanofibers were treated hydrothermally at 150°C for 1 h. Besides the utilized characterization techniques, PL study affirmed formation of ZnO. The produced nanofibers showed a good antibacterial activity which improves with increasing ZnO content. Overall, the present study opens new avenue to synthesize hybrid nanofibers by a facile procedure. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

A facile one-step approach to fabricate nylon-6 nanofibers decorated with silver nanoparticles by electrospinning has been reported. The method did not need post-treatments and could be carried out at ambient room condition. It employed the electrospinning solvents [formic acid and methoxy poly(ethylene glycol)] as a reducing agent for the conversion of AgNO 3 into Ag NPs during the solution preparation for electrospinning. The resultant Ag/nylon-6 hybrid nanofibers showed a smooth fibrous structure, with controlled size of Ag NPs uniformly dispersed throughout the nylon-6 matrix. The size of Ag NPs could be controlled by regulating the standing time duration of electrospinning solution. These hybrid nylon-6 composite nanofibers exhibited antibacterial activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus . Therefore, the obtained nylon-6 nanofibrous mats loaded with Ag NPs can be used in different areas such as wound dressing, water filters etc.

Human hair-based biocomposite nanofibers (NFs) have been fabricated by an electrospinning technique. Aqueous keratin extracted from human hair was successfully blended with poly(vinyl alcohol) (PVA). The focus here is on transforming into keratin/PVA nanofibrous membranes and insoluble property of electrospun NFs. The resulting hair-based NFs were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning colorimetry (DSC), and thermogravimetric analysis (TGA). Toward the potential use of these NFs after cross-linking with various weight fractions of glyoxal, its physicochemical properties, such as morphology, mechanical strength, crystallinity, and chemical structure were investigated. Keratin/PVA ratio of 2/1 NFs with 6 wt%-glyoxal showed good uniformity in fiber morphology and suitable mechanical properties, and excellent antibacterial activity providing a potential application of hair-based NFs in biomedical field.

In this work, different fractions of solvent-induced polymer degraded solution were mixed with freshly prepared solution of same polymer, and its effect on fiber morphology of electrospun mats was investigated. Nylon-6 solution in formic acid was allowed to degrade for 3 weeks and different fractions of it were mixed with freshly prepared nylon-6 solution to get the electrospun mats. FE-SEM images of the mats indicated that the a large amount of sub-nanofibers (

Highly porous fibers were prepared by water-bath electrospinning from pure poly(ɛ-caprolactone) (PCL), and its blends with methoxy poly(ethylene glycol) (MPEG). These fibers were further analyzed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and gravimetric as well as contact angle measurement. SEM images showed that the fibers diameters as well as pores diameter on the fibers were affected by the weight ratio of MPEG/PCL. DSC and XRD not only revealed suppression of crystallinity of PCL but also indicated the presence of trace amount of MPEG in PCL water-bath collected fibers. The potential use of these hydrophilic porous electrospun fibrous mats as scaffolding materials was evaluated in vitro using mouse osteoblasts (MC3T3-E1) as reference cell lines. Cytotoxicity assessment of the fiber mats indicated that the porous electrospun mat containing trace amount of MPEG was nontoxic to the cell. Cell culture results showed that porous fibrous mats were good in promoting the cell attachment and proliferation. This novel electrospun matrix could be used as potential tissue scaffold material.