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Materials Research Bulletin 02/2013; 47:2140–2147.. · 2.11 Impact Factor
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Colloids and Surfaces A Physicochemical and Engineering Aspects 11/2012; · 2.24 Impact Factor
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Journal of Luminescence 09/2012; · 2.10 Impact Factor
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Macromolecular Research 09/2012; · 1.15 Impact Factor
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Colloids and Surfaces A Physicochemical and Engineering Aspects 06/2012; · 2.24 Impact Factor
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Journal of Molecular Catalysis A Chemical 06/2012; · 2.95 Impact Factor
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ABSTRACT: In this study, a new hierarchical nanostructure consisting of zinc oxide (ZnO) and titanium dioxide (TiO2) was prepared by an electrospinning process followed by a hydrothermal technique for use as a photocatalyst for dye degradation.
First, the electrospinning of a colloidal solution consisting of titanium isopropoxide/poly(vinyl acetate)/zinc nanoparticles
was performed to produce polymeric nanofibers embedded in solid nanoparticles. Calcination of the obtained electrospun nanofiber
mats in air at 600 °C produced TiO2 nanofibers containing ZnO nanoparticles (i.e., ZnO-doped TiO2 nanofibers). The ZnO nanoparticles formed were then exploited as seeds to produce the outgrowth ZnO branches around the TiO2 nanofibers using the hydrothermal technique. Photodegradation of methyl red and rhodamine B (RB) dyes was examined individually
using four photocatalysts: ZnO nanoparticles prepared by the same hydrothermal technique, pristine TiO2 nanofibers, ZnO-doped TiO2 nanofibers and the produced nanostructure. The results showed that the introduced ZnO-TiO2 hierarchical nanostructure can eliminate all the methyl red dye within 90 min and the rhodamine B dye within 105 min. However,
the other three nanostructures could not totally remove any of the dyes, even after 3 h. Therefore, the introduced nanostructure
has higher photocatalytic activity than any of its ingredients individually, which highlights the advantages of synthesizing
this novel structure.
Keywordszinc oxide-titanium dioxide-nanofibers-photocatalytic reactions-electrospinning-hydrothermal-methyl red-rhodamine B
Macromolecular Research 05/2012; 18(3):233-240. · 1.15 Impact Factor
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ABSTRACT: As titanium oxide is a well-known photocatalyst, we investigated the effects of silver content and nanostructural morphology
on the photocatalytic degradation of two dyes, methylene blue and rhodamine B. Two nano-formulations were utilized, including
nanofibers and nanoparticles. Silver-grafted titanium oxide nanofibers were synthesized using the electrospinning of silver
nitrate/titanium isopropoxide/poly(vinyl acetate) sol-gel. The nanoparticulate form was obtained by calcination of a ground
powder prepared from the same electrospun sol-gel. The results affirmed the advantage of the silver-grafted titanium oxide
nanostructures over the silver-free ones. Increasing the silver content in the nanofibers led to increases in their surface
area, which is an important parameter in heterogeneous catalytic chemical reactions. Therefore, the results strongly suggest
the use of silver-grafted titanium oxide in a nanofibrous form. These results further support utilizing Agloaded titanium
oxide nanofibers as a photocatalyst.
KeywordsSliver-grafted titanium oxide-Nanofibers-Electrospinning-Photocatalytic reactions-Methylene blue-Rhodamine B
Fibers and Polymers 05/2012; 11(5):700-709. · 0.84 Impact Factor
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ABSTRACT: Titanium dioxide-cadmium oxide (TiO2/CdO) nanofibers were prepared by the electrospinning technique followed by a single-step calcination from a solution of titanium
isopropoxide and cadmium acetate dihydrate. Scanning electron microscopy, transmission electron microscopy, and the Brunauer–Emmett–Teller
technique were employed to characterize the as-spun nanofibers as well as the calcined product. The specific surface area
of the calcined product was calculated to be 65.3067m2g−1. X-ray powder diffractometry analysis was conducted on the samples to study their chemical composition as well as their crystallographic
structure. The results obtained indicated that the prepared nanostructure product can eliminate all of the methyl orange dye
within about 75min, whereas the pristine titanium dioxide nanofibers could not eliminate more than 50% even after 180min.
Journal of Materials Science 05/2012; 45(5):1272-1279. · 2.02 Impact Factor
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ABSTRACT: Gallium arsenide (GaAs) does have superior electronic properties compared with silicon. For instant, it has a higher saturated
electron velocity and higher electron mobility. Weak mechanical properties and high production cost are the main drawbacks
of this interesting semiconductor. In this study, we are introducing production of GaAs nanofibers by electrospinning methodology
as a very low cost and yielding distinct product technique. In general, nano-fibrous shape is strongly improving the physical
properties due to the high surface area to volume ratio of this nanostructure. The mechanical and environmental properties
of the GaAs compound have been modified since GaAs nanofibers have been produced as a core inside a poly(vinyl alcohol) (PVA)
shell. GaAs/PVA nanofibers were prepared by electrospinning of gallium nitrate/PVA solution in presence of arsenic vapor.
The whole process was carried out in a closed hood equipped with nitrogen environment. FT-IR, XPS, TGA and UV-Vis spectroscopy
analyses were utilized to confirm formation of GaAs compound. Transmission electron microscope (TEM) analysis has revealed
that the synthesized GaAs compound is crystalline and does have nano-fibrous shape as a core inside PVA nanofibers. To precisely
recommend the prepared GaAs nanofiber mats to be utilized in different applications, we have measured the electric conductivity
and the band gap energies of the prepared nanofiber mats. Overall, the obtained results affirmed that the proposed strategy
successfully remedied the drawbacks of the reported GaAs structures and did not affect the main physical properties of this
important semiconductor.
KeywordsOptical materials-Gallium arsenide-Nanostructured materials-Sol-gel processes-Semiconductors
Fibers and Polymers 04/2012; 11(3):384-390. · 0.84 Impact Factor
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ABSTRACT: In this study, nanofiber mats consisting of two potential metal oxides were produced by electrospinning technique. An aqueous
solution of zinc acetate dihydrate and germanium isopropoxide was mixed with polyvinyl alcohol solution to prepare a sol–gel
that was electrospun at 20kV. The obtained nanofiber mats were dried under a vacuum at 80°C for 24h and then calcined in
air at different temperatures and soaking times. Physiochemical characterizations have affirmed that nanofibers composed of
zinc oxide-germanium dioxide (ZnO–GeO2) can be prepared by calcination at different temperatures. Scanning electron microscopy (SEM), transmission electron microscopy
(TEM), and the Brunauer–Emmett–Teller (BET) technique were employed to characterize the as-spun nanofibers and the calcined
product. The specific surface area of the calcined product decreased with increases in temperature. X-ray powder diffractometery
(XRD) analysis was used to study the chemical composition and the crystallographic structure. The optical properties of the
as-prepared ZnO–GeO2 nanofibers were also studied.
Journal of Materials Science 04/2012; 45(14):3833-3840. · 2.02 Impact Factor
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ABSTRACT: In the present study, nanofibers consisting of manganese monoxide (MnO), which is hard to prepare because of the chemical
activity of the manganese metal, and the popular Mn3O4 have been synthesized via the electrospinning technique. The nanofibers were obtained by electrospinning of an aqueous sol–gel
consisting of manganese acetate tetra-hydrate and poly(vinyl alcohol). The obtained nanofiber mats were dried in vacuum at
80°C for 24h and then calcined in argon atmosphere at 900°C for 5h. According to X-ray diffraction results, the obtained
nanofibers contain 65% MnO. Transmission electron microscope analysis reveals good crystallinity of the produced nanofibers.
UV–visible spectroscopic analysis has indicated that the produced nanofibers have two band-gap energies, 2 and 3.7eV, which
enhances utilizing of the nanofibers in different applications.
Applied Physics A 04/2012; 95(3):769-776. · 1.63 Impact Factor
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Ceramics International 04/2012; · 1.75 Impact Factor
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ABSTRACT: Dextran is a versatile biomacromolecule for preparing electrospun nanofibrous membranes by blending with either water-soluble bioactive agents or hydrophobic biodegradable polymers for biomedical applications. In this study, an antibacterial electrospun scaffold was prepared by electrospinning of a solution composed of dextran, polyurethane (PU) and ciprofloxacin HCl (CipHCl) drug. The obtained nanofiber mats have good morphology. The mats were characterized by various analytical techniques. The interaction parameters between fibroblasts and the PU-dextran and PU-dextran-drug scaffolds such as viability, proliferation, and attachment were investigated. The results indicated that the cells interacted favorably with the scaffolds especially the drug-containing one. Moreover, the composite mat showed good bactericidal activity against both of Gram-positive and Gram-negative bacteria. Overall, our results conclude that the introduced scaffold might be an ideal biomaterial for wound dressing applications.
Carbohydrate Polymers 01/2012; 90(4):1786-1793. · 3.63 Impact Factor
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ABSTRACT: a b s t r a c t The role of lactic acid (LA) on the polymer crystallization chain conformation and the surface modifi-cation of the electrospun nylon-6 fibers were examined. The effect of different amounts of LA on the polymer crystallization chain conformation of nylon-6 mat was evaluated using XRD, FT-IR and Raman spectroscopy whereas the surface modification of the electrospun mats was examined by FE-SEM, contact angle and mechanical properties measurement. It was found that the transition of meta-stable g-form into the thermodynamically stable a-form was achieved by increasing the amounts of LA in the blend mixture. The adhesive property of LA was found to be responsible for the transformation from non-bonded to the point-bonded structure of nanofibers in the electrospun nylon-6 mat. The resultant LA/nylon-6 hybrid mat with improved hydrophilicity and mechanical properties may be a potential candidate for tissue scaffold.
Polymer 10/2011; 52(2011):4851-4856. · 3.44 Impact Factor
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ABSTRACT: In this study, nanobranched TiO2 nanofibers and silver loaded nanobranched TiO2 nanofibers were prepared by electrospinning technique followed by TiCl4 aqueous solution treatment and silver photodeposition method. Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were employed to investigate the morphology of the products. X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS) were conducted on the samples to study their chemical composition as well as crystallographic structure. The photocatalytic activities of these produced nanofibers were examined with two organic dyes, methylene blue and methyl orange, under ultraviolet (UV) light irradiation. The effect of nanobranches and silver modification on TiO2 nanofibers was revealed in the photocatalysis process. The photocatalytic degradation rates of silver loaded on nanobranched TiO2 nanofibers were 1.6 and 1.7 times as that of pure TiO2 nanofibers in the presence of methylene blue and methyl orange, respectively, which indicated silver nanoparticles combined nanobranches modified on the surface of TiO2 nanofibers could enhance the photocatalytic ability.
Journal of Nanoscience and Nanotechnology 08/2011; 11(8):6886-92. · 1.56 Impact Factor
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ABSTRACT: In this study, a biological evaluation of the antimicrobial activity of Zn-doped titania nanofibers was carried out using Escherichia coli ATCC 52922 (Gram negative) and Staphylococcus aureus ATCC 29231 (Gram positive) as model organisms. The utilized Zn-doped titania nanofibers were prepared by the electrospinning of a sol-gel composed of zinc nitrate, titanium isopropoxide, and polyvinyl acetate; the obtained electrospun nanofibers were vacuum dried at 80°C and then calcined at 600°C. The physicochemical properties of the synthesized nanofibers were determined by X-ray diffraction pattern, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron probe microanalysis, thermogravimetry, and transmission electron microscopy (TEM). The antibacterial activity and the acting mechanism of Zn-doped titania nanofibers against bacteria were investigated by calculation of minimum inhibitory concentration and analyzing the morphology of the bacterial cells following the treatment with nanofibers solution. Our investigations reveal that the lowest concentration of Zn-doped titania nanofibers solution inhibiting the growth of S. aureus ATCC 29231 and E. coli ATCC 52922 strains is found to be 0.4 and 1.6 μg/ml, respectively. Furthermore, Bio-TEM analysis demonstrated that the exposure of the selected microbial strains to the nanofibers led to disruption of the cell membranes and leakage of the cytoplasm. In conclusion, the combined results suggested doping promotes antimicrobial effect; synthesized nanofibers possess a very large surface-to-volume ratio and may damage the structure of the bacterial cell membrane, as well as depress the activity of the membranous enzymes which cause bacteria to die in due course.
Applied Microbiology and Biotechnology 07/2011; 93(2):743-51. · 3.42 Impact Factor
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ABSTRACT: In this study, a good combination consisting of electrospun titanium dioxide (TiO(2)) nanofibers incorporated with high purity hydroxyapatite (HAp) nanoparticles (NPs) and antimicrobial silver NPs is introduced for hard tissue engineering applications. The synthesized nanofibers were characterized by various state of art techniques like; SEM, XRD, TEM, TEM EDS and XPS analyses. SEM results confirmed well oriented nanofibers and good dispersion of HAp and silver NPs, respectively. XRD results demonstrated well crystalline feature of three components used for electrospinning. Silver NPs were having a diameter in range of 5-8 nm indicated by TEM analysis. Moreover, TEM EDS analysis demonstrated the presence of each component with good dispersion over TiO(2) nanofiber. The surface analyses of nanofibers were investigated by XPS which indicated the presence of silver NPs on the surfaces of nanofibers. The obtained nanofibers were checked for antimicrobial activity by using two model organisms E. coli and S. aureus. Subsequently, antimicrobial tests have indicated that the prepared nanofibers do possess high bactericidal effect. Accordingly, these results strongly recommend the use of obtained nanofiber mats as future implant materials.
Journal of Materials Science Materials in Medicine 09/2010; 21(9):2551-9. · 2.32 Impact Factor
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ABSTRACT: Recently, bimetallic nanostructures have received special interest due to their promising chemical and physical properties. In the literature, various complicated processes have been reported for the preparation of several bimetallic materials in a nanoparticulate shape. In this study, nanofibers, rather than nanoparticles, composed of cobalt and nickel are introduced; these nanofibers have been prepared by a facile technique, electrospinning. Typically, calcination of electrospun mats originating from nickel acetate, cobalt acetate, and poly(vinyl alcohol) in argon atmosphere led to complete elimination of the utilized polymer and abnormal decomposition of the metallic acetates to produce CoNi nanofibers. Physiochemical characterization indicated that both Ni and Co are uniformly distributed along the obtained nanofibers in the same profile which indicates that Ni and Co have been combined at the crystalline level. The prepared CoNi nanofibers revealed better magnetic properties compared with those of Co-doped Ni and pristine Ni nanofibers and have potential for use as nickel-based soft magnetic materials.
08/2010;
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ABSTRACT: First, electrospinning of colloidal solution consisting of titanium isopropoxide/poly(vinyl acetate) zinc nanoparticles has been achieved to produce polymeric nanofibers embedding solid nanoparticles. Calcination of the obtained electrospun nanofiber mats in air at 600°C has been revealed to produce TiO₂ nanofibers containing ZnO nanoparticles; ZnO-doped TiO₂ nanofibers. The formed ZnO nanoparticles have been exploited as seeds to outgrow ZnO branches around the TiO₂ nanofibers using a hydrothermal technique. As anode in lithium ion battery, the prepared nanostructure exhibited a high rate capacity of 1232mAhg⁻¹.
Bioceramics Development and Applications. 01/2010;
