Search

Nanofibers can be interleaved into polymers and improvements in mechanical properties such as resistance to impact, delamination and debonding as well as enhanced ductility can be obtained. In this work, GFRP laminated composites were interleaved to non-woven nylon 6,6 nanofiber mats which were generated by the electrospinning method. Four kinds of configurations were considered; two pure configurations where GFRP had two and four glass fiber layers and the other two kinds of nanofiber modified configurations that had one and three nylon 6,6 nanofiber mats being interleaved in GFRP. Those specimens were then investigated for their impact resistance, energy absorption and tensile strength capabilities in regard to low-velocity impact and tensile tests. The results showed that adding nylon 6,6 nanofiber mats can increase energy absorption values of the modified specimens, but some decrease in load capacities could be observed.

WOS: 000519806700073, In this study, composites composed of glass fiber reinforced-epoxy laminates interleaved with electrospun polyvinylchloride (PVC) nano-fibres were designed for radar absorption investigations. The laminated composites which were produced in special molds were obtained by placing woven glass fibers between each of PVC nanofiber mats, and the composites were produced in three different forms as pure, multi-walled carbon nanotubes doped and graphene doped. The morphologies of the PVC nanofiber mats were analyzed by scanning electron microscope. The radar absorption efficiencies of the composites in the individual and different combinations were measured in the 3-8 GHz frequency band. Experimental results show that the produced graphene-added composite material has improvable microwave absorption effect at several points in 3-8 GHz band to provide excellent absorption in future studies. The graphene doped structure was found to have a certain absorption characteristic up to 33.82% at a constant frequency. Besides, various strong absorption frequency points have been obtained in the related frequency range. The cascaded graphene doped composite layers can provide broadband absorption for stealth technology.

WOS: 000343613000026 PubMed ID: 25256476 We report on a facile and robust method by which surface of electrospun cellulose acetate (CA) nanofibers can be chemically modified with cationic polymer brushes for DNA adsorption. The surface of CA nanofibers was functionalized by growing poly[(ar-vinylbenzyl)trimethylammonium chloride)] [poly(VBTAC)] brushes through a multi-step chemical sequence that ensures retention of mechanically robust nanofibers. Initially, the surface of the CA nanofibers was modified with RAFT chain transfer agent. Poly(VBTAC) brushes were then prepared via RAFT-mediated polymerization from the nanofiber surface. DNA adsorption capacity of CA nanofibrous web surface functionalized with cationic poly(VBTAC) brushes was demonstrated. The reusability of these webs was investigated by measuring the adsorption capacity for target DNA in a cyclic manner. In brief, CA nanofibers surface-modified with cationic polymer brushes can be suitable as membrane materials for filtration, purification, and/or separation processes for DNA. (C) 2014 Elsevier Ltd. All rights reserved. EU FP7-PEOPLE-RG Marie Curie-IRG (NANOWEB) [PIRG06-GA-2009-256428]; Turkish Academy of Sciences - Outstanding Young Scientists Award Program (TUBA-GEBIP); TUBITAK-BIDEB Dr T. Uyar acknowledges EU FP7-PEOPLE-2009-RG Marie Curie-IRG (NANOWEB, PIRG06-GA-2009-256428) and The Turkish Academy of Sciences - Outstanding Young Scientists Award Program (TUBA-GEBIP) for partial funding. A. Celebioglu acknowledges TUBITAK-BIDEB for the national PhD study scholarship.

In this report, morphology and fiber diameter differences of electrospun polysulfone (PSU) fibers on bacterial immobilization and bioremediation performance were evaluated. PSU fibers were produced with aligned or randomly oriented morphologies, and PSU fibers with thinner and thicker diameters were also produced. PSU fibers were utilized as carrier matrices for bacterial integration and the sample showing highest bacterial immobilization was tested for bioremediation of ammonium and methylene blue dye in water. It was found that randomly oriented and thinner PSU fibers are the optimal system for bacterial immobilization, hence bioremediation studies were performed with this sample. The results demonstrated that bacteria immobilized PSU fibers are promising candidates for simultaneous removal of ammonium and methylene blue dye, and they have a potential to be used in remediation of water systems. (C) 2017 Elsevier Ltd. All rights reserved.

In this report, ZnO nanoparticles embedded cellulose acetate (CA) fibrous membrane with multifunctional properties have been prepared through electrospinning method. The morphology of the electrospun composite membrane was analyzed by scanning electron microscope (SEM). It was found that the polymer concentration in the solution has a significant effect on the morphology of the fibers. The optical property of the sample was tested using photo luminescence (PL) spectra. There is no significant change in the emission features of cellulose acetate with the addition of ZnO. The anti-bacterial property of the sample was studied using disk diffusion method. The wettability of the pure and composite fibrous membrane was also studied by measuring the contact angle of water on the membrane. It was observed that the embedded ZnO in the CA was responsible for the hydrophobic nature of the surface. � 2013 Elsevier Ltd. All rights reserved.

Background: Glycosaminoglycans influence stem cell fate but their combination with biomaterials remains to be optimized. Results: GAG bound to scaffolds presented essential sulfation epitopes and proved biologically active. Conclusion: Use of plasma polymerized allylamine proved effective in functionalizing a fibrous extracellular matrix mimic. Significance: The biomaterial has broad applicability to stem cell culture and has potential future applications in regenerative medicine., As our understanding of what guides the behavior of multi- and pluripotent stem cells deepens, so too does our ability to utilize certain cues to manipulate their behavior and maximize their therapeutic potential. Engineered, biologically functionalized materials have the capacity to influence stem cell behavior through a powerful combination of biological, mechanical, and topographical cues. Here, we present the development of a novel electrospun scaffold, functionalized with glycosaminoglycans (GAGs) ionically immobilized onto the fiber surface. Bound GAGs retained the ability to interact with GAG-binding molecules and, crucially, presented GAG sulfation motifs fundamental to mediating stem cell behavior. Bound GAG proved to be biologically active, rescuing the neural differentiation capacity of heparan sulfate-deficient mouse embryonic stem cells and functioning in concert with FGF4 to facilitate the formation of extensive neural processes across the scaffold surface. The combination of GAGs with electrospun scaffolds creates a biomaterial with potent applicability for the propagation and effective differentiation of pluripotent stem cells.

An attempt has been made to prepare and characterise ammonium thiocyanate (NH4SCN) salt and a multiwall carbon nanotube (MWNT)-doped polyvinyl alcohol-based nanofibre mats using an electrospinning process. The X-ray diffraction result shows an improvement in the amorphous nature of composite electrolyte fibre mats with increasing concentrations of the MWNT filler. The DSC behaviour of these nanofibre mat exhibits better thermal response upon dispersal of the filler. Composite electrolyte nanofibre mat doped with 6 wt% MWNT shows optimum conductivity, viz., 5.8 � 10-4 Scm-1. The temperature dependence of the bulk electrical conductivity displays a combination of Arrhenius and Vogel-Tammam-Fulcher nature. Dielectric loss studies have also been used to understand the conduction process in the system. Jonscher power law seems to be obeyed during ac conductivity measurements of the fibre mats. � 2012 Springer-Verlag.

To examine the feasibility of developing flame-retardant-textile coated fabric systems with electrospun polyamide/boric acid nanocomposites, fiber webs coated on cotton substrates were developed to impart-fire retardant properties. The morphology of the polyamide/boric acid nanocomposite fibers was examined with scanning electron microscopy. The flame-retardant properties of coated fabric systems with different nanoparticle contents were assessed. The flame retardancy of the boric acid coated fabric systems was evaluated quantitatively with a flammability test apparatus fabricated on the basis of Consumer Product Safety Commission 16 Code of Federal Regulations part 1610 standard and also by thermogravimetric analysis. The 0.05 wt % boric acid nanocomposite fiber web coated on pure cotton fabric exhibited an increment in flame-spreading time of greater than 80%, and this indicated excellent fire protection. Also, the coated fabric systems with 0.05% boric acid nanocomposite fiber webs exhibited a distinct shift in the peak value in the thermal degradation profile and a 75% increase in char formation in the thermooxidative degradation profile, as indicated by the results of thermogravimetric analysis. The results show the feasibility of successfully imparting flame-retardant properties to cotton fabrics through the electrospinning of the polymer material with boric acid nanoparticles. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A highly deacetylated (97.5%) chitosan in 50% acetic acid was electrospun at moderate temperatures (25-70 °C) in the presence of a low content of polyethylene oxide (10 wt% PEO) to beadless nanofibers of 60-80 nm in diameter. A systematic quantitative analysis of the solution properties such as surface tension, conductivity, viscosity and acid concentration was conducted in order to shed light on the electrospinnability of this polysaccharide. Rheological properties of chitosan and PEO solutions were studied in order to explain how PEO improves the electrospinnability of chitosan. Positive charges on the chitosan molecule and its chain stiffness were considered as the main limiting factors for electrospinability of neat chitosan as compared to PEO, since surface tension and viscosity of the respective solutions were similar. Various blends of chitosan and PEO solutions with different component ratios were prepared (for 4 wt% total polymer content). A significant positive deviation from the additivity rule in the zero shear viscosity of chitosan/PEO blends was observed and believed to be a proof for strong hydrogen bonding between chitosan and PEO chains, making their blends electrospinnable. The impact of temperature and blend composition on the morphology and diameter of electrospun fibers was also investigated. Electrospinning at moderate temperatures (40-70 °C) helped to obtain beadless nanofibers with higher chitosan content. Additionally, it was found that higher chitosan content in the precursor blends led to thinner nanofibers. Increasing chitosan/PEO ratio from 50/50 to 90/10 led to a diameter reduction from 123 to 63 nm. Producing defect free nanofibrous mats from the electrospinning process and with high chitosan content is particularly promising for antibacterial film packaging and filtration applications. © 2011 Elsevier Ltd. All rights reserved.

Cerium doped SnO2 hollow nanofibers were synthesized by electrospinning. High resolution scanning electron microscope (HRSEM) and transmission electron microscopy (TEM) analysis showed hollow nanofibers with diameters around ?200 nm. The optimized substitution of Ce ion into SnO 2 lattices happened above 6 mol. % doping as confirmed by Powder X-ray diffraction (XRD) studies. Optical band gap was decreased by the doping confirming the direct energy transfer between f-electrons of rare earth ion and the SnO2 conduction or valence band. The compound also exhibited room temperature ferromagnetism with the saturation magnetization of 19 � 10-5 emu/g at 6 mol. %. This study demonstrates the Ce doped SnO 2 hollow nanofibers for applications in magneto-optoelectronic devices. � 2014 AIP Publishing LLC.

Cataloged from PDF version of article. We report on the suitability of water-soluble non-polymeric electrospun cyclodextrin (CD) nanofiber templates by using atomic layer deposition (ALD) to yield metal oxide tubes. To demonstrate this, water-soluble electrospun CD nanofibers were chosen as template to produce metal oxide tubes where we have tested two examples of ALD coatings, namely, Al2O3 and ZnO. After the ALD coating on the CD nanofibers, the CD core is simply dissolved in water to yield metal oxide tubes. Morphological investigations suggested that Al2O3 is smoother in contrast to ZnO which shows a grainy structure. Structural characterization evidenced amorphous Al2O3 and highly crystalline ZnO. Given the applicability of Al2O3 and ZnO in various contexts the ionic states of Al, Zn and O are also investigated. After the washing step to remove the CD core, Al2O3 developed some hydroxylation, while ZnO hosts various oxygen related functional groups. © The Royal Society of Chemistry 2014.

Silk fibroin from Bombyx mori silk cocoons was electrospun into silk nanofibers (SNFs). SEM images show that 9% w/v of SNFs was smooth and beadless having an average diameter in the range 30-150 nm. Curcumin (0.5-1.5 wt%) was incorporated into the silk fibroin solution and electrospun to obtain curcumin incorporated silk nanofibers (CSNFs) with diameters between 50 and 200 nm. The dispersion of curcumin in the SNFs was confirmed by TEM. The amorphous nature of curcumin upon incorporation into SNFs was confirmed by XRD. The functional groups of SNF and CSNF were confirmed by Fourier transform infrared spectroscopy. The SNFs and CSNFs were thermally stable up to ca 350 �C as evidenced by TGA. The glass transition temperature (Tg) of SNFs (168 �C) increased to 184 �C in the case of CSNFs as confirmed by DSC. The storage modulus, loss modulus and tan ? were determined by dynamic mechanical analysis. The percentages of porosity and water uptake of SNFs were 85% and 150%, respectively. The percentage in vitro cumulative release of curcumin at the end of the tenth day for 0.5, 1 and 1.5 wt% formulations was 82%, 84% and 80%, respectively. � 2013 Society of Chemical Industry.

Cyclodextrins are one of the most promising materials for the development of products with advanced properties due to inclusion complex formation ability with a wide variety of substances. More specifically, incorporation of cyclodextrins into electrospun nanofibrous materials is considered as potential candidates for functional textile applications. This study examines the electrospinning of thermoplastic polyurethane (TPU) nanofibres including β-cyclodextrin and investigates the effects of β-cyclodextrin (β-CD) on resultant fibre properties. TPU/CD nanofibres were characterized by scanning electron microscopy, FTIR, TGA and DSC analysis. Additionally phenolphthalein absorption tests were applied. It was observed that the incorporation of β-CD increased the mean fibre diameter and heterogeneity of nanofibrous membranes. The effects of β-CD on the thermal properties of TPU membranes were shown. It was proven that β-CD within TPU nanostructure could be able to form inclusion complexes. TPU/CD nanofibres are believed to have good potentials for functional textile applications. © 2013 Elsevier Ltd.

We produced functional nanowebs, containing vanillin, having prolonged shelf-life and high temperature stability facilitated by cyclodextrin (CD) inclusion complexation. Polyvinyl alcohol (PVA) nanowebs incorporating vanillin/cyclodextrin inclusion complex (vanillin/CD-IC) were produced via electrospinning technique. The vanillin/CD-IC was prepared with three types of CDs; alpha-CD, beta-CD and gamma-CD to find out the most favourable CD type for the stabilization of vanillin. PVA/vanillin/CD-IC nanofibres, having fibre diameters around similar to 200 nm, were successfully electrospun from aqueous mixture of PVA and vanillin/CD-IC. Our results indicated that vanillin with enhanced durability and high temperature stability was achieved for PVA/vanillin/CD-IC nanowebs due to complexation of vanillin with CD, whereas the PVA nanofibres without CD-IC could not effectively preserve the vanillin. Additionally, we observed that PVA/vanillin/gamma-CD-IC nanoweb was more effective for the stabilization and slow release of vanillin suggesting that the strength of interaction between vanillin and the gamma-CD cavity is stronger when compared to alpha-CD and beta-CD. (C) 2012 Elsevier Ltd. All rights reserved.

Conference name: Materials Research Society Symposium (MRS) Proceedings, 2011 Materials Research Society (MRS) Fall Meeting & Exhibit, Date of Conference: November 28-December 2, 2011 Al 2O 3 and AlN nanotubes were fabricated by depositing conformal thin films via atomic layer deposition (ALD) on electrospun nylon 66 (PA66) nanofiber templates. Depositions were carried out at 200°C, using trimethylaluminum (TMAl), water (H 2O), and ammonia (NH 3) as the aluminum, oxygen, and nitrogen precursors, respectively. Deposition rates of Al 2O 3 and AlN at this temperature were ∼1.05 and 0.86 Å/cycle. After the depositions, Al 2O 3- and AlN-coated nanofibers were calcinated at 500°C for 2 h in order to remove organic components. Nanotubes were characterized by using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). AlN nanotubes were polycrystalline as determined by high resolution TEM (HR-TEM) and selected area electron diffraction (SAED). TEM images of all the samples reported in this study indicated uniform wall thicknesses. © 2012 Materials Research Society.

In this study, we aimed to produce functional polyvinyl alcohol (PVA) electrospun nanowebs containing essential oil; eugenol (EG), that have long-term durability and high temperature stability due to cyclodextrin (CD) inclusion complexation.

The aim of this study is to produce electrospun cyclodextrin (CD) nanofibers without using a carrier polymer matrix.

Magnetoresponsive polymer-based fibrous nanocomposites belonging to the broad category of stimuli-responsive materials, is a relatively new class of “soft” composite materials, consisting of magnetic nanoparticles embedded within a polymeric fibrous matrix. The presence of an externally applied magnetic field influences the properties of these materials rendering them useful in numerous technological and biomedical applications including sensing, magnetic separation, catalysis and magnetic drug delivery. This study deals with the fabrication and characterization of magnetoresponsive nanocomposite fibrous membranes consisting of methacrylic random copolymers based on methyl methacrylate (MMA) and 2-(acetoacetoxy)ethyl methacrylate (AEMA) (MMA-co-AEMA) and oleic acid-coated magnetite (OA·Fe3O4) nanoparticles. The AEMA moieties containingβ-ketoester side-chain functionalities were introduced for the first time in this type of materials, because of their inherent ability to bind effectively onto inorganic surfaces providing an improved stabilization. For membrane fabrication the electrospinning technique was employed and a series of nanocomposite membranes was prepared in which the polymer content was kept constant and only the inorganic (OA·Fe3O4) content varied. Further to the characterization of these materials in regards to their morphology, composition and thermal properties, assessment of their magnetic characteristics disclosed tunable superparamagnetic behaviour at ambient temperature.

[EN] Fibronectin (FN) assembles into fibrillar networks by cells through an integrin-dependent mechanism. We have recently shown that simple FN adsorption onto poly(ethyl acrylate) surfaces (PEA), but not control polymer (poly(methyl acrylate), PMA), also triggered FN organization into a physiological fibrillar network. FN fibrils exhibited enhanced biological activities in terms of myogenic differentiation compared to individual FN molecules. In the present study, we investigate the influence of topological cues on the material-driven FN assembly and the myogenic differentiation process. Aligned and random electrospun fibers were prepared. While FN fibrils assembled on the PEA fibers as they do on the smooth surface, the characteristic distribution of globular FN molecules observed on flat PMA transformed into non-connected FN fibrils on electrospun PMA, which significantly enhanced cell differentiation. The direct relationship between the fibrillar organization of FN at the material interface and the myogenic process was further assessed by preparing FN gradients on smooth PEA and PMA films. Isolated FN molecules observed at one edge of the substrate gradually interconnected with each other, eventually forming a fully developed network of FN fibrils on PEA. In contrast, FN adopted a globular-like conformation along the entire length of the PMA surface, and the FN gradient consisted only of increased density of adsorbed FN. Correspondingly, the percentage of differentiated cells increased monotonically along the FN gradient on PEA but not on PMA. This work demonstrates an interplay between material chemistry and topology in modulating material-driven FN fibrillogenesis and cell differentiation. © 2011 Springer Science+Business Media, LLC., The support of the Spanish Ministry of Science and Innovation through project MAT2009-14440-C02-01 is acknowledged. CIBER-BBN is an initiative funded by the VI National R&D&i Plan 2008–2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. This work was supported by funds for research in the field of Regenerative Medicine through the collaboration agreement from the Conselleria de Sanidad (Generalitat Valenciana), and the Instituto de Salud Carlos III.

Electrospinning is a desired method to produce ultrathin fibers for tissue engineering. In order to mimic the nanofibrous structure of the extracellular matrix (ECM) poly(propylene carbonate) ultrathin fibers were electrospun using N,N-dimethyl acetamide as solvent. Cationic surfactant, cetyl trimethyl ammonium bromide, was found to aid in the formation of beadless fibers of poly(propylene carbonate). Electrospinning parameters viz. concentration of polymer and that of the surfactant used as an additive, flow rate, electrostatic field, and effect of inner diameter of the needle were investigated and optimized. Scanning electron microscopy showed porous scaffold and fibers of diameter ranging from nano- to submicron range. FTIR spectroscopy and thermal analysis of the obtained fibers ensured the complete evaporation of solvent and optimal thermal stability of fibers for tissue engineering applications. The prepared fibers possess Young's modulus of 10.19 and 26.39 GPa with the tensile strengths of 22.11 and 21.29 MPa under dry and wet conditions, respectively. The fiber mat was measured to have a porosity of 48% and exhibited competent water retention capacity of 64%. Furthermore the scaffold was found to support the adhesion of mouse NIH 3T3 fibroblasts proving its mettle as a potential scaffold for tissue engineering applications. � 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The present work reports the preparation of Poly L-Lactide (PLLA) and Curcumin loaded Poly L-Lactide (CPLLA) nanofibers by electrospinning. A series of PLLA solution (12 wt%) and C-PLLA (12 wt% PLLA) solution containing Curcumin (0. 5 wt% and 1 wt%)) were electrospun into nanofibers. SEM images showed the average diameter of PLLA and C-PLLA in the range of 50-200 nm. The TEM images showed the dispersion of Curcumin on C-PLLA nanofibers. The XRD pattern indicated decreases of crystallinity with the increase in the amount of Curcumin. The characteristic peak of Curcumin was confirmed by FTIR. The TGA results showed the degradation of PLLA and C-PLLA close to 300 �C. The percentage porosity and the contact angle of PLLA were found to be 90. 2% and 115�3 � with deionised water, respectively. The water uptake percentage was found to be 17. 6%. The percentage cumulative release of Curcumin at the end of 8th day for 0. 5 and 1. 0 wt% formulations was 81. 4�1. 3 and 86. 7�1. 7% respectively. The in-vitro biological cytotoxicity studies were performed using C6 glioma cells and NIH 3T3 fibroblast by MTT assay and SEM analysis. � 2012 The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Zein nanofibers containing cyclodextrins (zein/CD) were produced via electrospinning. Three types of CDs (alpha-CD, beta-CD and gamma-CD) having 10%, 25% and 50% (w/w) were individually incorporated into zein nanofibers. SEM imaging elucidated that the morphologies of the electrospun zein/CD nanofibers depended on the CD type and weight percentage. The incorporation of CDs in zein improved the electrospinnability and bead-free nanofibers were obtained at lower zein concentrations. Zein/CD nanofibers having fiber diameters similar to 100-400 nm were obtained depending on the zein concentrations, types and weight percentages of CD. XRD studies revealed that CDs were mostly distributed without forming crystalline aggregates for zein/CD nanofibers containing lower weight percentage of CDs. The surface analyses of zein/CD nanofibers by ATR-FTIR and XPS indicated that some of the CDs were present on the fiber surface. Thermal analyses showed that zein/beta-CD nanofibers have shown higher glass transition temperatures and higher degradation temperature with increasing CD content. (C) 2012 Elsevier Ltd. All rights reserved.

This work evaluates the influence of electrospinning process parameters on the mean diameter and standard deviation of fiber diameters in electrospun poly(ethyl methacrylate) (PEMA). Processing conditions were selected using Taguchi's statistical method. Oriented and unoriented electrospun mats with good mechanical properties were produced and demonstrated with tensile stress-strain diagrams. Differential scanning calorimetry (DSC) experiments showed that the polymer chains were forced into non-equilibrium conformations due to electrospinning. Enthalpic recovery during a heating scan is shown by an endothermic peak in the initial DSC heating scan that disappears in subsequent heating scans. An increase in the glass transition temperature with respect to PEMA films shows that the polymer is not equilibrated by heating above glass transition. Cell attachment was tested with MC3T3-E1 pre-osteoblastic cells cultured for short time periods on the electrospun mats. It is shown that the cells present less extended morphology with more diffuse perimetral focal adhesions than cells cultured on flat substrates. A tendency of cells to align in the direction of the substrate fibers in oriented electrospun membranes was also found. © 2010 Elsevier Ltd. All rights reserved., The language revision of this paper was funded by the Universidad Politecnica de Valencia, Spain.

In this study, polymeric nanofibrous composites containing anatase TiO 2 short nanofibers (TiO2-SNF) were successfully produced via electrospinning. The fabrication of the nanofibrous composite structure includes two steps. First, anatase TiO2 nanofibers were obtained by calcination of electrospun PVP/TiO2 nanofibers and then crushed into short nanofibers ranging from few microns in length. Second, these TiO 2-SNF were dispersed into polymer solutions and then electrospun into nanofibrous composites. We obtained nanofibers containing TiO2-SNF from different polymer types including PMMA, PAN, PET and PC. The SEM and TEM imaging indicated that some of the TiO2-SNF were fully covered by the polymeric matrix whereas some TiO2-SNF were partially covered and/or stick on the surface of the fibers. The photocatalytic activity of nanofibrous composites containing TiO2-SNF was evaluated by monitoring the photocatalytic decomposition of a model dye (rhodamine-6G) under UV irradiation. © 2011 Elsevier B.V. All rights reserved.

Cataloged from PDF version of article. Poly(methyl methacrylate) (PMMA) nanofibers containing the inclusion complex forming beta-cyclodextrin (β-CD) were successfully produced by means of electrospinning in order to develop functional nanofibrous webs for organic vapor waste treatment. Electrospinning of uniform PMMA nanofibers containing different loadings of β-CD (10%, 25% and 50% (w/w)) was achieved. The surface sensitive spectroscopic techniques; X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) showed that some of the β-CD molecules are present on the surface of the PMMA nanofibers, which is essential for the trapping of organic vapors by inclusion complexation. Direct pyrolysis mass spectrometry (DP-MS) studies showed that PMMA nanowebs containing β-CD can entrap organic vapors such as aniline, styrene and toluene from the surroundings due to inclusion complexation with β-CD that is present on the fiber surface. Our study showed that electrospun nanowebs functionalized with cyclodextrins may have the potential to be used as molecular filters and/or nanofilters for the treatment of organic vapor waste and air filtration purposes.

We reported fabrication of electrospun nano-fibrous ion-exchange membrane (IEM) composed of sulfonated poly(ether ether ketone) (SPEEK). Prepared membrane was employed for electro-dialytic separation of Na+ from Mg 2+ or Ca2+, which is an urgent problem for the production potable water from brackish water and chlor-alkali industries. Nano-fibrous membrane was successfully fabricated onto spun-bonded non-woven polypropylene fabric. Electrospun SPEEK (ESPEEK) and SPEEK thin film membrane's suitability, for the electro-dialytic separation of cations, was assessed by their conductivity measurements under different electrolytic environment using electrochemical impedance spectroscopy. Counter-ion transport number and membrane permselectivity were strongly depended on the nature of counter-ions. ESPEEK membrane showed very low selectivity (about negligible) for Mg 2+ and Ca2+, because formation of nano-fibrous pore or channels, which restricted the migration of bi-valent cations. Additionally, very low flux and electro-transport efficiency for bi-valent cations in compare with Na+ across ESPEEK membrane, suggested its possible application for electro-driven separation of mono-valent and bi-valent electrolytes. Electrospun nano-fibrous IEMs may be the promising candidate for electro-dialytic selective separation of ions depending on their charge and hydrated ionic size. � 2010 Elsevier B.V. All rights reserved.

Electrospinning has been used to successfully create polystyrene (PS) nanofibers containing either of three different types of cyclodextrin (CD); α-CD, β-CD, and γ-CD. These three CDs are chosen because they have different sized cavities that potentially allow for selective inclusion complex (IC) formation with molecules of different size or differences in affinity of IC formation with one type of molecule. The CD containing electrospun PS nanofibers (PS/CD) were initially characterized by scanning electron microscopy (SEM) to determine the uniformity of the fibers and their fiber diameter distributions. X-ray photoelectron spectroscopy (XPS) was used to quantitatively determine the concentration of each CD on the different fiber surfaces. Static time-of-flight secondary ion mass spectrometry (static-ToF-SIMS) showed the presence of each type of CD on the PS nanofibers by the detection of both the CD sodium adduct molecular ions (M + Na+) and lower molecular weight oxygen containing fragment ions. The comparative efficiency of the PS/CD nanofibers/nanoweb for removing phenolphthalein, a model organic compound, from solution was determined by UV-vis spectrometry, and the kinetics of phenolphthalein capture was shown to follow the trend PS/α-CD > PS/β-CD > PS/γ-CD. Direct pyrolysis mass spectrometry (DP-MS) was also performed to ascertain the relative binding strengths of the phenolphthalein for the CD cavities, and the results showed the trend in the interaction strength was β-CD > γ-CD > α-CD. Our results demonstrate that nanofibers produced by electrospinning that incorporate cyclodextrins with different sized cavities can indeed filter organic molecules and can potentially be used for filtration, purification, and/or separation processes. © 2010 American Chemical Society.

Composite materials based on poly(e-caprolactone) (PCL) and carbon nanofibres (CNFs) were processed by solvent casting and electrospinning. The main objective was to investigate the effects of the CNFs on the microstructural, thermal and mechanical properties of the PCL matrix composites processed by two different routes. The hybrid materials obtained with different CNF content (1, 3 and 7 wt%) were analysed by electron microscopy (FESEM), differential scanning calorimeter (DSC), thermogravimetry (TGA) and mechanical testing. The composite films showed a good dispersion in the PCL matrix while electrospun samples were consisted of homogeneous and uniform fibres up to 3 wt% CNFs with average fibre diameter ranged between 0.5 and 1 μm. Composite films and mats revealed an increased crystallization temperature with respect to the neat PCL matrix. Mechanical properties of solvent cast films and electrospun mats were assessed by uniaxial tensile tests. A stiffness increase was achieved in PCL films depending on the CNF content, while mechanical properties of mats were only slightly affected by CNF introduction.

BiOCl and Bi2O3 nanosheet like structures were produced by electrospinning. The morphological changes were observed by changing precursor (BiOCl3 and Bi(NO3)3·5H 2O) concentrations. These nanosheets were analyzed by XRD, which reveals that the crystal structures of BiOCl and Bi2O3 belonged to tetragonal and beta-phase systems respectively. Both nanostructures were employed for the photodegradation of Alizarin Red S (ARS) dye under UV light (

Date of Conference: 18-21 June 2012 Conference name: Technical Proceedings of the 2012 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2012 Organic-inorganic core-shell nanofibers were fabricated by combining electrospinning and atomic layer deposition (ALD). In the first step, nylon66 (polymeric organic core) nanofibers having different average fiber diameters (∼100 nm, ∼250 nm and ∼650 nm) were electrospun by using different solvent systems and polymer concentrations. In the second step, uniform and conformal layer of zinc oxide (ZnO) (inorganic shell) with precise thickness (∼90 nm) and composition on the round surface of the nylon nanofibers were deposited by ALD. The core-shell nylon66-ZnO nanofibers have shown unique properties such as structural flexibility due to the polymeric core and photocatalytic activity due to the ZnO shell layer.

Electrospinning has been used to produce micrometer size fibers, both solid and hollow from non-covalently associating small molecules of a low grade hydrocarbon reject of crude oil, asphaltene. Asphaltene defined as a solubility class of crude oil is by no means a polymer but relatively large organic molecule of molecular weight ranging from 500 to 1000 Dalton. The production of asphaltene fibers is feasible by electrospinning because of its unique molecular structure which allows molecular aggregation. Fibers with diameter ranging from 2–20 μm were successfully spun from an asphaltene in toluene solution. Adding 2% hydrogen peroxide enhances electrospinning, leading to formation of hollow fibers, whereas adding 2% water inhibits electrospinning. The structure and morphology of the electrospun fibers were investigated with optical microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and time-of-flight secondary ion mass spectroscopy. The electrospun asphaltene fibers offer the potential for direct fabrication of membranes without use of multiple synthetic steps, complex electrospinning designs, or post processing surface treatments.

Our purpose was to produce functional polyvinyl alcohol (PVA) electrospun nanowebs containing vanillin having prolonged shelf-life and high temperature stability facilitated by cyclodextrin inclusion complexation.