WorldWideScience

Sample records for hybrid nanofiber sheets

  1. Precisely Assembled Nanofiber Arrays as a Platform to Engineer Aligned Cell Sheets for Biofabrication

    Directory of Open Access Journals (Sweden)

    Vince Beachley

    2014-08-01

    Full Text Available A hybrid cell sheet engineering approach was developed using ultra-thin nanofiber arrays to host the formation of composite nanofiber/cell sheets. It was found that confluent aligned cell sheets could grow on uniaxially-aligned and crisscrossed nanofiber arrays with extremely low fiber densities. The porosity of the nanofiber sheets was sufficient to allow aligned linear myotube formation from differentiated myoblasts on both sides of the nanofiber sheets, in spite of single-side cell seeding. The nanofiber content of the composite cell sheets is minimized to reduce the hindrance to cell migration, cell-cell contacts, mass transport, as well as the foreign body response or inflammatory response associated with the biomaterial. Even at extremely low densities, the nanofiber component significantly enhanced the stability and mechanical properties of the composite cell sheets. In addition, the aligned nanofiber arrays imparted excellent handling properties to the composite cell sheets, which allowed easy processing into more complex, thick 3D structures of higher hierarchy. Aligned nanofiber array-based composite cell sheet engineering combines several advantages of material-free cell sheet engineering and polymer scaffold-based cell sheet engineering; and it represents a new direction in aligned cell sheet engineering for a multitude of tissue engineering applications.

  2. Fabrication of Carbon Nanotube Polymer Actuator Using Nanofiber Sheet

    Science.gov (United States)

    Kato, Hayato; Shimizu, Akikazu; Sato, Taiga; Kushida, Masahito

    2017-11-01

    Carbon nanotube polymer actuators were developed using composite nanofiber sheets fabricated by multi-walled carbon nanotubes(MWCNTs) and poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). Nanofiber sheets were fabricated by electrospinning method. The effect of flow rate and polymer concentration on nanofiber formation were verified for optimum condition for fabricating nanofiber sheets. We examined the properties of MWCNT/PVDF-HFP nanofiber sheets, as follows. Electrical conductivity and mechanical strength increased as the MWCNT weight ratio increased. We fabricated carbon nanotube polymer actuators using MWCNT/PVDF-HFP nanofiber sheets and succeeded in operating of our actuators.

  3. Single clay sheets inside electrospun polymer nanofibers

    Science.gov (United States)

    Sun, Zhaohui

    2005-03-01

    Nanofibers were prepared from polymer solution with clay sheets by electrospinning. Plasma etching, as a well controlled process, was used to supply electrically excited gas molecules from a glow discharge. To reveal the structure and arrangement of clay layers in the polymer matrix, plasma etching was used to remove the polymer by controlled gasification to expose the clay sheets due to the difference in reactivity. The shape, flexibility, and orientation of clay sheets were studied by transmission and scanning electron microscopy. Additional quantitative information on size distribution and degree of exfoliation of clay sheets were obtained by analyzing electron micrograph of sample after plasma etching. Samples in various forms including fiber, film and bulk, were thinned by plasma etching. Morphology and dispersion of inorganic fillers were studied by electron microscopy.

  4. A novel electrospun silk fibroin/hydroxyapatite hybrid nanofibers

    International Nuclear Information System (INIS)

    Ming, Jinfa; Zuo, Baoqi

    2012-01-01

    A novel electrospinning of silk fibroin/hydroxyapatite hybrid nanofibers with different composition ratios was performed with methanoic acid as a spinning solvent. The silk fibroin/hydroxyapatite hybrids containing up to 30% hydroxyapatite nanoparticles could be electrospun into the continuous fibrous structure. The electrospun silk fibroin/hydroxyapatite hybrid nanofibers showed bigger diameter and wider diameter distribution than pure silk fibroin nanofibers, and the average diameter gradually increased from 95 to 582 nm. At the same time, the secondary structure of silk fibroin/hydroxyapatite nanofibers was characterized by X-ray diffraction, Fourier transform infrared analysis, and DSC measurement. Comparing with the pure silk fibroin nanofibers, the crystal structure of silk fibroin was mainly amorphous structure in the hybrid nanofibers. X-ray diffraction results demonstrated the hydroxyapatite crystalline nature remained as evidenced from the diffraction planes (002), (211), (300), and (202) of the hydroxyapatite crystallites, which was also confirmed by Fourier transform infrared analysis. The thermal behavior of hybrid nanofibers exhibited the endothermic peak of moisture evaporation ranging from 86 to 113 °C, and the degradation peak at 286 °C appeared. The SF/HAp nanofibers mats containing 30% HAp nanoparticles showed higher breaking tenacity and extension at break for 1.1688 ± 0.0398 MPa and 6.55 ± 1.95%, respectively. Therefore, the electrospun silk fibroin/hydroxyapatite hybrid nanofibers should be provided potentially useful options for the fabrication of biomaterial scaffolds for bone tissue engineering. -- Highlights: ► The novel SF/HAp nanofibers were directly prepared by electrospinning method. ► The nanofiber diameter had significant related to the content of HAp. ► The crystal structure of silk fibroin was mainly amorphous structure in the hybrid nanofibers. ► The HAp crystals existing in the hybrid nanofibers were characterized

  5. 3D tissue formation by stacking detachable cell sheets formed on nanofiber mesh.

    Science.gov (United States)

    Kim, Min Sung; Lee, Byungjun; Kim, Hong Nam; Bang, Seokyoung; Yang, Hee Seok; Kang, Seong Min; Suh, Kahp-Yang; Park, Suk-Hee; Jeon, Noo Li

    2017-03-23

    We present a novel approach for assembling 3D tissue by layer-by-layer stacking of cell sheets formed on aligned nanofiber mesh. A rigid frame was used to repeatedly collect aligned electrospun PCL (polycaprolactone) nanofiber to form a mesh structure with average distance between fibers 6.4 µm. When human umbilical vein endothelial cells (HUVECs), human foreskin dermal fibroblasts, and skeletal muscle cells (C2C12) were cultured on the nanofiber mesh, they formed confluent monolayers and could be handled as continuous cell sheets with areas 3 × 3 cm 2 or larger. Thicker 3D tissues have been formed by stacking multiple cell sheets collected on frames that can be nested (i.e. Matryoshka dolls) without any special tools. When cultured on the nanofiber mesh, skeletal muscle, C2C12 cells oriented along the direction of the nanofibers and differentiated into uniaxially aligned multinucleated myotube. Myotube cell sheets were stacked (upto 3 layers) in alternating or aligned directions to form thicker tissue with ∼50 µm thickness. Sandwiching HUVEC cell sheets with two dermal fibroblast cell sheets resulted in vascularized 3D tissue. HUVECs formed extensive networks and expressed CD31, a marker of endothelial cells. Cell sheets formed on nanofiber mesh have a number of advantages, including manipulation and stacking of multiple cell sheets for constructing 3D tissue and may find applications in a variety of tissue engineering applications.

  6. Hybrid electrospun chitosan-phospholipids nanofibers for transdermal drug delivery

    DEFF Research Database (Denmark)

    Mendes, Ana Carina Loureiro; Gorzelanny, Christian; Halter, Natalia

    2016-01-01

    Chitosan (Ch) polysaccharide was mixed with phospholipids (P) to generate electrospun hybrid nanofibers intended to be used as platforms for transdermal drug delivery. Ch/P nanofibers exibithed average diameters ranging from 248 +/- 94 nm to 600 +/- 201 nm, depending on the amount of phospholipids...... used. Fourier Transformed Infra-Red (FTIR) spectroscopy and Dynamic Light Scattering (DLS) data suggested the occurrence of electrostatic interactions between amine groups of chitosan with the phospholipid counterparts. The nanofibers were shown to be stable for at least 7 days in Phosphate Buffer...... culture plate (control). The release of curcumin, diclofenac and vitamin B12, as model drugs, from Ch/P hybrid nanofibers was investigated, demonstrating their potential utilization as a transdermal drug delivery system....

  7. Hybrid electrospun chitosan-phospholipids nanofibers for transdermal drug delivery.

    Science.gov (United States)

    Mendes, Ana C; Gorzelanny, Christian; Halter, Natalia; Schneider, Stefan W; Chronakis, Ioannis S

    2016-08-20

    Chitosan (Ch) polysaccharide was mixed with phospholipids (P) to generate electrospun hybrid nanofibers intended to be used as platforms for transdermal drug delivery. Ch/P nanofibers exibithed average diameters ranging from 248±94nm to 600±201nm, depending on the amount of phospholipids used. Fourier Transformed Infra-Red (FTIR) spectroscopy and Dynamic Light Scattering (DLS) data suggested the occurrence of electrostatic interactions between amine groups of chitosan with the phospholipid counterparts. The nanofibers were shown to be stable for at least 7days in Phosphate Buffer Saline (PBS) solution. Cytotoxicity studies (WST-1 and LDH assays) demonstrated that the hybrid nanofibers have suitable biocompatibility. Fluorescence microscopy, also suggested that L929 cells seeded on top of the CH/P hybrid have similar metabolic activity comparatively to the cells seeded on tissue culture plate (control). The release of curcumin, diclofenac and vitamin B12, as model drugs, from Ch/P hybrid nanofibers was investigated, demonstrating their potential utilization as a transdermal drug delivery system. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Formation of inorganic nanofibers by heat-treatment of poly(vinyl alcohol-zirconium compound hybrid nanofibers

    Directory of Open Access Journals (Sweden)

    Nakane K.

    2013-01-01

    Full Text Available Poly(vinyl alcohol-zirconium compound hybrid nanofibers (precursors were formed by electrospinning employing water as a solvent for the spinning solution. The precursors were converted into oxide (ZrO2, carbide (ZrC or nitride (ZrN nanofibers by heating them in air, Ar or N2 atmospheres. Monoclinic ZrO2 nanofibers with high-specific surface area were obtained by heat-treatment of the precursors in air. ZrC and ZrN nanofibers could be obtained below theoretical temperatures calculated from thermodynamics data.

  9. Post-Heat Treatment and Mechanical Assessment of Polyvinyl Alcohol Nanofiber Sheet Fabricated by Electrospinning Technique

    Directory of Open Access Journals (Sweden)

    Mahir Es-saheb

    2014-01-01

    Full Text Available Polyvinyl alcohol (PVA sheets based nanofibers were produced by electrospinning technique. Postheat treatment of the produced PVA sheets with temperatures both below and above Tg to improve the mechanical properties of this material is conducted. The morphology, microstructures, and thermal degradation of the nanofibers sheets produced were investigated using scanning electron microscopy (SEM, transmission electron microscope (TEM, and thermal gravimetric analysis (TGA. Produced nanofibers are compact, and entangled with each other, with diameters from around 150 to 210. Some mechanical characteristics of the successfully produced PVA sheets, and heat-treated, are then conducted and assessed employing uniaxial tensile tests at different speeds ranging from 1 mm/min to 100 mm/min. The tensile test results obtained show that the PVA sheets are strain rate sensitive with increasing strength as the speed (i.e., strain rate increases. The yield tensile stress ranges from 2.411 to 6.981 MPa, the ductility (i.e., elongation percent from ∼21 to 60%, and Young modulus ranges from 103 to 0.137 KPa. However, for heat-treated samples, it is found that the yield strength increases almost by ∼35–40% more than the values of untreated cases with values reaching up to about 3.627–9.63 MPa.

  10. Platelet graphite nanofibers for electrochemical sensing and biosensing: the influence of graphene sheet orientation.

    Science.gov (United States)

    Ambrosi, Adriano; Sasaki, Toshio; Pumera, Martin

    2010-02-01

    Here, we demonstrate that platelet graphite nanofibers (PGNFs) exhibit fast heterogeneous electron-transfer rates for a wide variety of compounds such as FeCl(3), ferrocyanide, dopamine, uric acid, ascorbic acid, and the reduced form of beta-nicotinamide adenine dinucleotide. The electrochemical properties of PGNFs are superior to those of multiwalled carbon nanotubes (MWCNTs) or graphite microparticles (GMPs). Transmission electron microscopy and Raman spectroscopy reveal that this arises from the unique graphene sheet orientation of such platelet nanofibers, which accounts for their unparalleled high ratio of graphene edge planes versus basal planes.

  11. Piezoelectric and optoelectronic properties of electrospinning hybrid PVDF and ZnO nanofibers

    Science.gov (United States)

    Ma, Jian; Zhang, Qian; Lin, Kabin; Zhou, Lei; Ni, Zhonghua

    2018-03-01

    Polyvinylidene fluoride (PVDF) is a unique ferroelectric polymer with significant promise for energy harvesting, data storage, and sensing applications. ZnO is a wide direct band gap semiconductor (3.37 eV), commonly used as ultraviolet photodetectors, nanoelectronics, photonicsand piezoelectric generators. In this study, we produced high output piezoelectric energy harvesting materials using hybrid PVDF/ZnO nanofibers deposited via electrospinning. The strong electric fields and stretching forces during the electrospinning process helps to align dipoles in the nanofiber crystal such that the nonpolar α-phase (random orientation of dipoles) is transformed into polar β-phase in produced nanofibers. The effect of the additional ZnO nanowires on the nanofiber β-phase composition and output voltage are investigated. The maximum output voltage generated by a single hybrid PVDF and ZnO nanofiber (33 wt% ZnO nanowires) is over 300% of the voltage produced by a single nanofiber made of pure PVDF. The ZnO NWs served not only as a piezoelectric material, but also as a semiconducting material. The electrical conductivity of the hybrid PVDF/ZnO nanofibers increased by more than a factor of 4 when exposed under ultraviolet (UV) light.

  12. MnO-carbon hybrid nanofiber composites as superior anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang, Jian-Gan; Yang, Ying; Huang, Zheng-Hong; Kang, Feiyu

    2015-01-01

    MnO-carbon hybrid nanofiber composites are fabricated by electrospinning polyimide/manganese acetylacetonate precursor and a subsequent carbonization process. The composition, phase structure and morphology of the composites are characterized by scanning and transmission electron microscopy, X-ray diffraction and thermogravimetric analysis. The results indicate that the composites exhibit good nanofibrous morphology with MnO nanoparticles uniformly encapsulated by carbon nanofibers. The hybrid nanofiber composites are used directly as freestanding anodes for lithium-ion batteries to evaluate their electrochemical properties. It is found that the optimized MnO-carbon nanofiber composite can deliver a high reversible capacity of 663 mAh g −1 , along with excellent cycling stability and good rate capability. The superior performance enables the composites to be promising candidates as an anode alternative for high-performance lithium-ion batteries

  13. Synergistic tungsten oxide/organic framework hybrid nanofibers for electrochromic device application

    Science.gov (United States)

    Dulgerbaki, Cigdem; Komur, Ali Ihsan; Nohut Maslakci, Neslihan; Kuralay, Filiz; Uygun Oksuz, Aysegul

    2017-08-01

    We report the first successful applications of tungsten oxide/conducting polymer hybrid nanofiber assemblies in electrochromic devices. Poly(3,4-ethylenedioxythiophene)/tungsten oxide (PEDOT/WO3) and polypyrrole/tungsten oxide (PPy/WO3) composites were prepared by an in situ chemical oxidative polymerization of monomers in different ionic liquids; 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide (BMIMTFSI) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMPTFSI). Electrospinning process was used to form hybrid nanofibers from chemically synthesized nanostructures. The electrospun hybrid samples were compared from both morphological and electrochemical perspectives. Importantly, deposition of nanofibers from chemically synthesized hybrids can be achieved homogenously, on nanoscale dimensions. The morphologies of these assemblies were evaluated by SEM, whereas their electroactivity was characterized by cyclic voltammetry. Electrochromic devices made from hybrid nanofiber electrodes exhibited highest chromatic contrast of 37.66% for PEDOT/WO3/BMIMPF6, 40.42% for PPy/WO3/BMIMBF4 and show a strong electrochromic color change from transparent to light brown. Furthermore, the nanofiber devices exhibit outstanding stability when color switching proceeds, which may ensure a versatile platform for color displays, rear-view mirrors and smart windows.

  14. Biotemplated preparation of CdS nanoparticles/bacterial cellulose hybrid nanofibers for photocatalysis application

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jiazhi; Yu, Junwei [Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094 (China); Fan, Jun [School of Environment, Nanjing University, Nanjing 210093 (China); Sun, Dongping [Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094 (China); Tang, Weihua [Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094 (China); Yang, Xuejie [Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094 (China)

    2011-05-15

    In this work, we describe a novel facile and effective strategy to prepare micrometer-long hybrid nanofibers by deposition of CdS nanoparticles onto the substrate of hydrated bacterial cellulose nanofibers (BCF). Hexagonal phase CdS nanocrystals were achieved via a simple hydrothermal reaction between CdCl{sub 2} and thiourea at relatively low temperature. The prepared pristine BCF and the CdS/BCF hybrid nanofibers were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV-vis absorption spectroscopy (UV-vis), and X-ray photoelectron spectroscopy (XPS). The results reveal that the CdS nanoparticles were homogeneously deposited on the BCF surface and stabilized via coordination effect. The CdS/BCF hybrid nanofibers demonstrated high-efficiency photocatalysis with 82% methyl orange (MO) degradation after 90 min irradiation and good recyclability. The results indicate that the CdS/BCF hybrid nanofibers are promising candidate as robust visible light responsive photocatalysts.

  15. Biotemplated preparation of CdS nanoparticles/bacterial cellulose hybrid nanofibers for photocatalysis application

    International Nuclear Information System (INIS)

    Yang, Jiazhi; Yu, Junwei; Fan, Jun; Sun, Dongping; Tang, Weihua; Yang, Xuejie

    2011-01-01

    In this work, we describe a novel facile and effective strategy to prepare micrometer-long hybrid nanofibers by deposition of CdS nanoparticles onto the substrate of hydrated bacterial cellulose nanofibers (BCF). Hexagonal phase CdS nanocrystals were achieved via a simple hydrothermal reaction between CdCl 2 and thiourea at relatively low temperature. The prepared pristine BCF and the CdS/BCF hybrid nanofibers were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV-vis absorption spectroscopy (UV-vis), and X-ray photoelectron spectroscopy (XPS). The results reveal that the CdS nanoparticles were homogeneously deposited on the BCF surface and stabilized via coordination effect. The CdS/BCF hybrid nanofibers demonstrated high-efficiency photocatalysis with 82% methyl orange (MO) degradation after 90 min irradiation and good recyclability. The results indicate that the CdS/BCF hybrid nanofibers are promising candidate as robust visible light responsive photocatalysts.

  16. Biotemplated preparation of CdS nanoparticles/bacterial cellulose hybrid nanofibers for photocatalysis application.

    Science.gov (United States)

    Yang, Jiazhi; Yu, Junwei; Fan, Jun; Sun, Dongping; Tang, Weihua; Yang, Xuejie

    2011-05-15

    In this work, we describe a novel facile and effective strategy to prepare micrometer-long hybrid nanofibers by deposition of CdS nanoparticles onto the substrate of hydrated bacterial cellulose nanofibers (BCF). Hexagonal phase CdS nanocrystals were achieved via a simple hydrothermal reaction between CdCl(2) and thiourea at relatively low temperature. The prepared pristine BCF and the CdS/BCF hybrid nanofibers were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV-vis absorption spectroscopy (UV-vis), and X-ray photoelectron spectroscopy (XPS). The results reveal that the CdS nanoparticles were homogeneously deposited on the BCF surface and stabilized via coordination effect. The CdS/BCF hybrid nanofibers demonstrated high-efficiency photocatalysis with 82% methyl orange (MO) degradation after 90 min irradiation and good recyclability. The results indicate that the CdS/BCF hybrid nanofibers are promising candidate as robust visible light responsive photocatalysts. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Hybrid Piezoelectric/Fiber-Optic Sensor Sheets

    Science.gov (United States)

    Lin, Mark; Qing, Xinlin

    2004-01-01

    Hybrid piezoelectric/fiber-optic (HyPFO) sensor sheets are undergoing development. They are intended for use in nondestructive evaluation and long-term monitoring of the integrity of diverse structures, including aerospace, aeronautical, automotive, and large stationary ones. It is anticipated that the further development and subsequent commercialization of the HyPFO sensor systems will lead to economic benefits in the form of increased safety, reduction of life-cycle costs through real-time structural monitoring, increased structural reliability, reduction of maintenance costs, and increased readiness for service. The concept of a HyPFO sensor sheet is a generalization of the concept of a SMART Layer(TradeMark), which is a patented device that comprises a thin dielectric film containing an embedded network of distributed piezoelectric actuator/sensors. Such a device can be mounted on the surface of a metallic structure or embedded inside a composite-material structure during fabrication of the structure. There is has been substantial interest in incorporating sensors other than piezoelectric ones into SMART Layer(TradeMark) networks: in particular, because of the popularity of the use of fiber-optic sensors for monitoring the "health" of structures in recent years, it was decided to incorporate fiber-optic sensors, giving rise to the concept of HyPFO devices.

  18. Gas diffusion electrode based on electrospun Pani/CNF nanofibers hybrid for proton exchange membrane fuel cells (PEMFC) applications

    Energy Technology Data Exchange (ETDEWEB)

    Hezarjaribi, M.; Jahanshahi, M., E-mail: mjahan@nit.ac.ir; Rahimpour, A.; Yaldagard, M.

    2014-03-01

    A novel hybrid system has been investigated based on polyaniline/carbon nanofiber (Pani/CNF) electrospun nanofibers for modification of gas diffusion electrode (GDE) in proton exchange membrane fuel cells (PEMFC). Pani/CNF hybrid nanofibers were synthesized directly on carbon paper by electrospinning method. For preparation of catalyst ink, 20 wt.% Pt/C electrocatalyst with a platinum loading of 0.4 mg cm{sup −2} was prepared by polyol technique. SEM studies applied for morphological study of the modified GDE with hybrid nanofibers. This technique indicated that the electrospun nanofibers had a diameter of roughly 100 nm. XRD patterns also showed that the average size of Pt nanoparticles was about 2 nm. Subsequently, comparison of the hybrid electrode electrochemical behavior and 20 wt.% Pt/C commercial one was studied by cyclic voltammetry experiment. The electrochemical data indicated that the hybrid electrode exhibited higher current density (about 15 mA cm{sup −2}) and ESA (160 m{sup 2} gr{sup −1}) than commercial Pt/C with amount of about 10 mA cm{sup −2} and 114 m{sup 2} gr{sup −1}, respectively. The results herein demonstrate that Pani/CNF nanofibers can be used as a good alternative electrode material for PEMFCs.

  19. Chitosan(PEO)/silica hybrid nanofibers as a potential biomaterial for bone regeneration.

    Science.gov (United States)

    Toskas, Georgios; Cherif, Chokri; Hund, Rolf-Dieter; Laourine, Ezzeddine; Mahltig, Boris; Fahmi, Amir; Heinemann, Christiane; Hanke, Thomas

    2013-05-15

    New hybrid nanofibers prepared with chitosan (CTS), containing a total amount of polyethylene oxide (PEO) down to 3.6wt.%, and silica precursors were produced by electrospinning. The solution of modified sol-gel particles contained tetraethoxysilane (TEOS) and the organosilane 3-glycidyloxypropyltriethoxysilane (GPTEOS). This is rending stable solution toward gelation and contributing in covalent bonding with chitosan. The fibers encompass advantages of biocompatible polymer template silicate components to form self-assembled core-shell structure of the polymer CTS/PEO encapsulated by the silica. Potential applicability of this hybrid material to bone tissue engineering was studied examining its cellular compatibility and bioactivity. The nanofiber matrices were proved cytocompatible when seeded with bone-forming 7F2-cells, promoting attachment and proliferation over 7 days. These found to enhance a fast apatite formation by incorporation of Ca(2+) ions and subsequent immersion in modified simulated body fluid (m-SBF). The tunable properties of these hybrid nanofibers can find applications as active biomaterials in bone repair and regeneration. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Polyaniline-coated freestanding porous carbon nanofibers as efficient hybrid electrodes for supercapacitors

    Science.gov (United States)

    Tran, Chau; Singhal, Richa; Lawrence, Daniel; Kalra, Vibha

    2015-10-01

    Three-dimensional, free-standing, hybrid supercapacitor electrodes combining polyaniline (PANI) and porous carbon nanofibers (P-CNFs) were fabricated with the aim to integrate the benefits of both electric double layer capacitors (high power, cyclability) and pseudocapacitors (high energy density). A systematic investigation of three different electropolymerization techniques, namely, potentiodynamic, potentiostatic, and galvanostatic, for electrodeposition of PANI on freestanding carbon nanofiber mats was conducted. It was found that the galvanostatic method, where the current density is kept constant and can be easily controlled facilitates conformal and uniform coating of PANI on three-dimensional carbon nanofiber substrates. The electrochemical tests indicated that the PANI-coated P-CNFs exhibit excellent specific capacitance of 366 F g-1 (vs. 140 F g-1 for uncoated porous carbon nanofibers), 140 F cm-3 volumetric capacitance, and up to 2.3 F cm-2 areal capacitance at 100 mV s-1 scan rate. Such excellent performance is attributed to a thin and conformal coating of PANI achieved using the galvanostatic electrodeposition technique, which not only provides pseudocapacitance with high rate capability, but also retains the double-layer capacitance of the underlying P-CNFs.

  1. Preparation of Pd/Bacterial Cellulose Hybrid Nanofibers for Dopamine Detection

    Directory of Open Access Journals (Sweden)

    Dawei Li

    2016-05-01

    Full Text Available Palladium nanoparticle-bacterial cellulose (PdBC hybrid nanofibers were synthesized by in-situ chemical reduction method. The obtained PdBC nanofibers were characterized by a series of analytical techniques. The results revealed that Pd nanoparticles were evenly dispersed on the surfaces of BC nanofibers. Then, the as-prepared PdBC nanofibers were mixed with laccase (Lac and Nafion to obtain mixture suspension, which was further modified on electrode surface to construct novel biosensing platform. Finally, the prepared electrochemical biosensor was employed to detect dopamine. The analysis result was satisfactory, the sensor showed excellent electrocatalysis towards dopamine with high sensitivity (38.4 µA·mM−1, low detection limit (1.26 µM, and wide linear range (5–167 µM. Moreover, the biosensor also showed good repeatability, reproducibility, selectivity and stability and was successfully used in the detection of dopamine in human urine, thus providing a promising method for dopamine analysis in clinical application.

  2. Multifunctional ZnO/Nylon 6 nanofiber mats by an electrospinning-electrospraying hybrid process for use in protective applications

    Energy Technology Data Exchange (ETDEWEB)

    Vitchuli, Narendiran; Shi Quan; McCord, Marian; Zhang Xiangwu [Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, NC 27695-8301 (United States); Nowak, Joshua; Bourham, Mohamed [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695-7909 (United States); Kay, Kathryn [Department of Microbiology, North Carolina State University, Raleigh, NC 27695-7610 (United States); Caldwell, Jane M; Breidt, Frederick, E-mail: bourham@ncsu.edu, E-mail: mmccord@ncsu.edu, E-mail: xiangwu_zhang@ncsu.edu [Department of Food Science, North Carolina Agricultural Research Service, North Carolina State University, Raleigh, NC 27695-7624 (United States)

    2011-10-15

    ZnO/Nylon 6 nanofiber mats were prepared by an electrospinning-electrospraying hybrid process in which ZnO nanoparticles were dispersed on the surface of Nylon 6 nanofibers without becoming completely embedded. The prepared ZnO/Nylon 6 nanofiber mats were evaluated for their abilities to kill bacteria or inhibit their growth and to catalytically detoxify chemicals. Results showed that these ZnO/Nylon 6 nanofiber mats had excellent antibacterial efficiency (99.99%) against both the Gram-negative Escherichia coli and Gram-positive Bacillus cereus bacteria. In addition, they exhibited good detoxifying efficiency (95%) against paraoxon, a simulant of highly toxic chemicals. ZnO/Nylon 6 nanofiber mats were also deposited onto nylon/cotton woven fabrics and the nanofiber mats did not significantly affect the moisture vapor transmission rates and air permeability values of the fabrics. Therefore, ZnO/Nylon 6 nanofiber mats prepared by the electrospinning-electrospraying hybrid process are promising material candidates for protective applications.

  3. Multifunctional ZnO/Nylon 6 nanofiber mats by an electrospinning–electrospraying hybrid process for use in protective applications

    Directory of Open Access Journals (Sweden)

    Narendiran Vitchuli, Quan Shi, Joshua Nowak, Kathryn Kay, Jane M Caldwell, Frederick Breidt, Mohamed Bourham, Marian McCord and Xiangwu Zhang

    2011-01-01

    Full Text Available ZnO/Nylon 6 nanofiber mats were prepared by an electrospinning–electrospraying hybrid process in which ZnO nanoparticles were dispersed on the surface of Nylon 6 nanofibers without becoming completely embedded. The prepared ZnO/Nylon 6 nanofiber mats were evaluated for their abilities to kill bacteria or inhibit their growth and to catalytically detoxify chemicals. Results showed that these ZnO/Nylon 6 nanofiber mats had excellent antibacterial efficiency (99.99% against both the Gram-negative Escherichia coli and Gram-positive Bacillus cereus bacteria. In addition, they exhibited good detoxifying efficiency (95% against paraoxon, a simulant of highly toxic chemicals. ZnO/Nylon 6 nanofiber mats were also deposited onto nylon/cotton woven fabrics and the nanofiber mats did not significantly affect the moisture vapor transmission rates and air permeability values of the fabrics. Therefore, ZnO/Nylon 6 nanofiber mats prepared by the electrospinning–electrospraying hybrid process are promising material candidates for protective applications.

  4. Biologically Active Polycaprolactone/Titanium Hybrid Electrospun Nanofibers for Hard Tissue Engineering

    DEFF Research Database (Denmark)

    Barakat, Nasser A. M.; Sheikh, Faheem A.; Al-Deyab, Salem S.

    2011-01-01

    In this study, a novel strategy to improve the bioactivity of polycaprolactone nanofibers is proposed. Incorporation of pure titanium nanoparticles into polycaprolactone nanofibers strongly enhances the precipitation of bone-like apatite materials when the doped nanofibers are soaked in a simulat...... nanofiber mats and the successful incorporation of the titanium nanoparticles make the prepared polycaprolactone nanofiber mat a proper candidate for the hard-tissue engineering applications....

  5. Analysis of alternative flow sheets for the hybrid chlorine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Gooding, Charles H. [Department of Chemical and Biomolecular Engineering, 209 Earle Hall, Clemson University, Clemson, SC 29634-0909 (United States)

    2009-05-15

    This paper reports the results of the most complete conceptual study conducted to date on hydrogen production using the hybrid chlorine cycle. Three alternative process flow sheets were developed, each capable of producing hydrogen at 35 C (308 K) and 21 bar. The alternative approaches differ primarily in the way HCl is isolated and converted to hydrogen and chlorine gases. Aspen Plus trademark simulation software was used to model the unit processes, supplemented where necessary by custom Excel spreadsheets. Major equipment was sized for a 200-million kg/yr plant; feasible materials of construction were identified; fixed capital investments and variable costs were estimated. Estimated net thermal efficiencies of the flow sheets range from 30% to 36%, based on the lower heating value of the hydrogen produced. With electrical power valued at $0.05/kWh, the cost of hydrogen produced by the hybrid chlorine cycle would be at least $3/kg. These results indicate that direct electrolysis of water is a more attractive way to produce hydrogen than any presently conceived version of the hybrid chlorine cycle. (author)

  6. Functionalized hybrid nanofibers to mimic native ECM for tissue engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Karuppuswamy, Priyadharsini [Center for Nanofibers and Nanotechnology, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, Singapore (Singapore); Department Physics and Nanotechnology, SRM University, Kattankulathur, Chennai (India); Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Venugopal, Jayarama Reddy, E-mail: nnijrv@nus.edu.sg [Center for Nanofibers and Nanotechnology, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, Singapore (Singapore); Navaneethan, Balchandar [Center for Nanofibers and Nanotechnology, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, Singapore (Singapore); Department Physics and Nanotechnology, SRM University, Kattankulathur, Chennai (India); Laiva, Ashang Luwang; Sridhar, Sreepathy; Ramakrishna, Seeram [Center for Nanofibers and Nanotechnology, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, Singapore (Singapore)

    2014-12-15

    Highlights: • Functionalized hybrid polymer mats fabricated for tissue engineering. • Hybrid polymer mats showed high surface area, high porosity and good wettability. • Incorporation of natural polymers modified the properties of nanofiber mats more biologically favorable for biomedical applications. - Abstract: Nanotechnology being one of the most promising technologies today shows an extremely huge potential in the field of tissue engineering to mimic the porous topography of natural extracellular matrix (ECM). Natural polymers are incorporated into the synthetic polymers to fabricate functionalized hybrid nanofibrous scaffolds, which improve cell and tissue compatibility. The present study identified the biopolymers – aloe vera, silk fibroin and curcumin incorporated into polycaprolactone (PCL) as suitable substrates for tissue engineering. Different combinations of PCL with natural polymers – PCL/aloe vera, PCL/silk fibroin, PCL/aloe vera/silk fibroin, PCL/aloe vera/silk fibroin/curcumin were electrospun into nanofibrous scaffolds. The fabricated two dimensional nanofibrous scaffolds showed high surface area, appropriate mechanical properties, hydrophilicity and porosity, required for the regeneration of diseased tissues. The nanofibrous scaffolds were characterized by Scanning electron microscope (SEM), porometry, Instron tensile tester, VCA optima contact angle measurement and FTIR to analyze the fiber diameter and morphology, porosity and pore size distribution, mechanical strength, wettability, chemical bonds and functional groups, respectively. The average fiber diameter of obtained fibers ranged from 250 nm to 350 nm and the tensile strength of PCL scaffolds at 4.49 MPa increased upto 8.3 MPa for PCL/silk fibroin scaffolds. Hydrophobicity of PCL decreased with the incorporation of natural polymers, especially for PCL/aloe vera scaffolds. The properties of as-spun nanofiber scaffolds showed their potential as promising scaffold materials in

  7. Functionalized hybrid nanofibers to mimic native ECM for tissue engineering applications

    International Nuclear Information System (INIS)

    Karuppuswamy, Priyadharsini; Venugopal, Jayarama Reddy; Navaneethan, Balchandar; Laiva, Ashang Luwang; Sridhar, Sreepathy; Ramakrishna, Seeram

    2014-01-01

    Highlights: • Functionalized hybrid polymer mats fabricated for tissue engineering. • Hybrid polymer mats showed high surface area, high porosity and good wettability. • Incorporation of natural polymers modified the properties of nanofiber mats more biologically favorable for biomedical applications. - Abstract: Nanotechnology being one of the most promising technologies today shows an extremely huge potential in the field of tissue engineering to mimic the porous topography of natural extracellular matrix (ECM). Natural polymers are incorporated into the synthetic polymers to fabricate functionalized hybrid nanofibrous scaffolds, which improve cell and tissue compatibility. The present study identified the biopolymers – aloe vera, silk fibroin and curcumin incorporated into polycaprolactone (PCL) as suitable substrates for tissue engineering. Different combinations of PCL with natural polymers – PCL/aloe vera, PCL/silk fibroin, PCL/aloe vera/silk fibroin, PCL/aloe vera/silk fibroin/curcumin were electrospun into nanofibrous scaffolds. The fabricated two dimensional nanofibrous scaffolds showed high surface area, appropriate mechanical properties, hydrophilicity and porosity, required for the regeneration of diseased tissues. The nanofibrous scaffolds were characterized by Scanning electron microscope (SEM), porometry, Instron tensile tester, VCA optima contact angle measurement and FTIR to analyze the fiber diameter and morphology, porosity and pore size distribution, mechanical strength, wettability, chemical bonds and functional groups, respectively. The average fiber diameter of obtained fibers ranged from 250 nm to 350 nm and the tensile strength of PCL scaffolds at 4.49 MPa increased upto 8.3 MPa for PCL/silk fibroin scaffolds. Hydrophobicity of PCL decreased with the incorporation of natural polymers, especially for PCL/aloe vera scaffolds. The properties of as-spun nanofiber scaffolds showed their potential as promising scaffold materials in

  8. Studies on soy protein isolate/polyvinyl alcohol hybrid nanofiber membranes as multi-functional eco-friendly filtration materials

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Qun; Zhu, Ming; Yu, Siruo; Sui, Gang, E-mail: suigang@mail.buct.edu.cn; Yang, Xiaoping

    2016-12-15

    Highlights: • Biodegradable filtration membranes were prepared. • Polar groups in the membrane surface helped capture fine particles. • Loading filtration efficiency can reach 99.99% in the case of small pressure drop. • Filtration membrane showed antimicrobial activity to Escherichia coli. - Abstract: A biodegradable and multifunctional air filtration membrane was prepared by electrospinning of soy protein isolate (SPI)/polyvinyl alcohol (PVA) system in this paper. The optimized SPI/PVA proportion in the spinning solution was determined according to the analyses of microstructure, surface chemical characteristic and mechanical property of the hybrid nanofiber membranes. Under the preferred preparation condition, two kinds of polymer materials displayed a good compatibility in the hybrid nanofibers, and a large number of polar groups existed in the membrane surface. The loading filtration efficiency of the nanofiber membrane with optimal material ratio and areal density can reach 99.99% after test of 30 min for fine particles smaller than 2.5 μm in the case of small pressure drop. Besides, this kind of filtration membrane showed an antimicrobial activity to Escherichia coli in the study. The SPI/PVA hybrid nanofiber membrane with proper material composition and microstructure can be used as a new type of high performance eco-friendly filtration materials.

  9. Studies on soy protein isolate/polyvinyl alcohol hybrid nanofiber membranes as multi-functional eco-friendly filtration materials

    International Nuclear Information System (INIS)

    Fang, Qun; Zhu, Ming; Yu, Siruo; Sui, Gang; Yang, Xiaoping

    2016-01-01

    Highlights: • Biodegradable filtration membranes were prepared. • Polar groups in the membrane surface helped capture fine particles. • Loading filtration efficiency can reach 99.99% in the case of small pressure drop. • Filtration membrane showed antimicrobial activity to Escherichia coli. - Abstract: A biodegradable and multifunctional air filtration membrane was prepared by electrospinning of soy protein isolate (SPI)/polyvinyl alcohol (PVA) system in this paper. The optimized SPI/PVA proportion in the spinning solution was determined according to the analyses of microstructure, surface chemical characteristic and mechanical property of the hybrid nanofiber membranes. Under the preferred preparation condition, two kinds of polymer materials displayed a good compatibility in the hybrid nanofibers, and a large number of polar groups existed in the membrane surface. The loading filtration efficiency of the nanofiber membrane with optimal material ratio and areal density can reach 99.99% after test of 30 min for fine particles smaller than 2.5 μm in the case of small pressure drop. Besides, this kind of filtration membrane showed an antimicrobial activity to Escherichia coli in the study. The SPI/PVA hybrid nanofiber membrane with proper material composition and microstructure can be used as a new type of high performance eco-friendly filtration materials.

  10. Facile Synthesis of Coaxial CNTs/MnOx-Carbon Hybrid Nanofibers and Their Greatly Enhanced Lithium Storage Performance.

    Science.gov (United States)

    Yang, Zunxian; Lv, Jun; Pang, Haidong; Yan, Wenhuan; Qian, Kun; Guo, Tailiang; Guo, Zaiping

    2015-12-01

    Carbon nanotubes (CNTs)/MnOx-Carbon hybrid nanofibers have been successfully synthesized by the combination of a liquid chemical redox reaction (LCRR) and a subsequent carbonization heat treatment. The nanostructures exhibit a unique one-dimensional core/shell architecture, with one-dimensional CNTs encapsulated inside and a MnOx-carbon composite nanoparticle layer on the outside. The particular porous characteristics with many meso/micro holes/pores, the highly conductive one-dimensional CNT core, as well as the encapsulating carbon matrix on the outside of the MnOx nanoparticles, lead to excellent electrochemical performance of the electrode. The CNTs/MnOx-Carbon hybrid nanofibers exhibit a high initial reversible capacity of 762.9 mAhg(-1), a high reversible specific capacity of 560.5 mAhg(-1) after 100 cycles, and excellent cycling stability and rate capability, with specific capacity of 396.2 mAhg(-1) when cycled at the current density of 1000 mAg(-1), indicating that the CNTs/MnOx-Carbon hybrid nanofibers are a promising anode candidate for Li-ion batteries.

  11. Carbon Nanofiber/3D Nanoporous Silicon Hybrids as High Capacity Lithium Storage Materials.

    Science.gov (United States)

    Park, Hyeong-Il; Sohn, Myungbeom; Kim, Dae Sik; Park, Cheolho; Choi, Jeong-Hee; Kim, Hansu

    2016-04-21

    Carbon nanofiber (CNF)/3D nanoporous (3DNP) Si hybrid materials were prepared by chemical etching of melt-spun Si/Al-Cu-Fe alloy nanocomposites, followed by carbonization using a pitch. CNFs were successfully grown on the surface of 3DNP Si particles using residual Fe impurities after acidic etching, which acted as a catalyst for the growth of CNFs. The resulting CNF/3DNP Si hybrid materials showed an enhanced cycle performance up to 100 cycles compared to that of the pristine Si/Al-Cu-Fe alloy nanocomposite as well as that of bare 3DNP Si particles. These results indicate that CNFs and the carbon coating layer have a beneficial effect on the capacity retention characteristics of 3DNP Si particles by providing continuous electron-conduction pathways in the electrode during cycling. The approach presented here provides another way to improve the electrochemical performances of porous Si-based high capacity anode materials for lithium-ion batteries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Carbon nanofibers with radially grown graphene sheets derived from electrospinning for aqueous supercapacitors with high working voltage and energy density

    Science.gov (United States)

    Zhao, Lei; Qiu, Yejun; Yu, Jie; Deng, Xianyu; Dai, Chenglong; Bai, Xuedong

    2013-05-01

    Improvement of energy density is an urgent task for developing advanced supercapacitors. In this paper, aqueous supercapacitors with high voltage of 1.8 V and energy density of 29.1 W h kg-1 were fabricated based on carbon nanofibers (CNFs) and Na2SO4 electrolyte. The CNFs with radially grown graphene sheets (GSs) and small average diameter down to 11 nm were prepared by electrospinning and carbonization in NH3. The radially grown GSs contain between 1 and a few atomic layers with their edges exposed on the surface. The CNFs are doped with nitrogen and oxygen with different concentrations depending on the carbonizing temperature. The supercapacitors exhibit excellent cycling performance with the capacity retention over 93.7% after 5000 charging-discharging cycles. The unique structure, possessing radially grown GSs, small diameter, and heteroatom doping of the CNFs, and application of neutral electrolyte account for the high voltage and energy density of the present supercapacitors. The present supercapacitors are of high promise for practical application due to the high energy density and the advantages of neutral electrolyte including low cost, safety, low corrosivity, and convenient assembly in air.

  13. Preparation of an amide group-connected graphene-polyaniline nanofiber hybrid and its application in supercapacitors.

    Science.gov (United States)

    Jianhua, Liu; Junwei, An; Yecheng, Zhou; Yuxiao, Ma; Mengliu, Li; Mei, Yu; Songmei, Li

    2012-06-27

    Polyaniline (PANI) nanofiber is grafted onto graphene to obtain a novel graphene-polyaniline (GP) hybrid. Graphene is activated using SOCl2 and reacts with PANI to form an amide group that intimately connects graphene and PANI. The existence of the amide group and its anchoring effect in the GP hybrid are confirmed and characterized by SEM, TEM, FT-IR, Raman, XPS and quantum chemistry analyses. Electrochemical tests reveal that the GP hybrid has high capacitance performances of 579.8 and 361.9 F g(-1) at current densities of 0.3 and 1 A g(-1). These values indicate superiority to materials interacted by van der Waals force. Long-term charge/discharge tests at high current densities show that the GP hybrid preserves 96% of its initial capacitance, demonstrating good electrochemical stability. The improved electrochemical performance suggests promising application of the GP hybrid in high-performance supercapacitors.

  14. Impact Energy Absorbing Capability of Metal/Polymer Hybrid Sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Kyungil; Kwon, O Bum; Park, Hyung Wook [Ulsan Nat’l Institute of Science and Technology, Ulsan (Korea, Republic of)

    2017-02-15

    Recently, the reduction of vehicle weight has been increasingly studied, in order to enhance the fuel efficiency of passenger cars. In particular, the seat frame is being studied actively, owing to considerations of driver safety from external impact damage. Therefore, this study focuses on high strength steel sheet (SPFC980)/polymer heterojunction hybrid materials, and their performance in regards to impact energy absorption. The ratio of impact energy absorption was observed to be relatively higher in the SPFC980/polymer hybrid materials under the impact load. This was found by calculating the equivalent flexural rigidity, which is the bending effect, according to the Castigliano theorem. An efficient wire-web structure was investigated through the simulation of different wire-web designs such as triangular, rectangular, octagonal, and hexagonal structures. The hexagonal wire-web structure was shown to have the least impact damage, according to the simulations. This study can be utilized for seat frame design for passengers’ safety, owing to efficient impact absorption.

  15. Flexible Hybrid Membranes with Ni(OH)2 Nanoplatelets Vertically Grown on Electrospun Carbon Nanofibers for High-Performance Supercapacitors.

    Science.gov (United States)

    Zhang, Longsheng; Ding, Qianwei; Huang, Yunpeng; Gu, Huahao; Miao, Yue-E; Liu, Tianxi

    2015-10-14

    The practical applications of transition metal oxides and hydroxides for supercapacitors are restricted by their intrinsic poor conductivity, large volumetric expansion, and rapid capacitance fading upon cycling, which can be solved by optimizing these materials to nanostructures and confining them within conductive carbonaceous frameworks. In this work, flexible hybrid membranes with ultrathin Ni(OH)2 nanoplatelets vertically and uniformly anchored on the electrospun carbon nanofibers (CNF) have been facilely prepared as electrode materials for supercapacitors. The Ni(OH)2/CNF hybrid membranes with three-dimensional macroporous architectures as well as hierarchical nanostructures can provide open and continuous channels for rapid diffusion of electrolyte to access the electrochemically active Ni(OH)2 nanoplatelets. Moreover, the carbon nanofiber can act both as a conductive core to provide efficient transport of electrons for fast Faradaic redox reactions of the Ni(OH)2 sheath, and as a buffering matrix to mitigate the local volumetric expansion/contraction upon long-term cycling. As a consequence, the optimized Ni(OH)2/CNF hybrid membrane exhibits a high specific capacitance of 2523 F g(-1) (based on the mass of Ni(OH)2, that is 701 F g(-1) based on the total mass) at a scan rate of 5 mV s(-1). The Ni(OH)2/CNF hybrid membranes with high mechanical flexibility, superior electrical conductivity, and remarkably improved electrochemical capacitance are condsidered as promising flexible electrode materials for high-performance supercapacitors.

  16. A multi-scaled hybrid orthopedic implant: bone ECM-shaped Sr-HA nanofibers on the microporous walls of a macroporous titanium scaffold

    Energy Technology Data Exchange (ETDEWEB)

    Han Yong; Zhou Jianhong; Zhang Lan; Xu Kewei, E-mail: yonghan@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2011-07-08

    We report here, for the first time, a novel multi-scaled hybrid orthopedic implant material consisting of a macroporous Ti scaffold, whose macropores' walls have a microporous titania layer which is fully covered with nanofibers of Sr-doped hydroxyapatite (Sr-HA). The microporous titania layer is formed on and within the Ti scaffold by micro-arc oxidation, which firmly binds to the Ti substrate and contains Ca{sup 2+}, Sr{sup 2+} and PO{sub 4}{sup 3-} ions. It is then hydrothermally treated to form Sr-HA nanofibers. During the hydrothermal treatment, Sr-HA nanoprisms nucleate from Ca{sub 0.5}Sr{sub 0.5}TiO{sub 3} pre-formed on the TiO{sub 2} and grow in length to nanofibers at the expense of Ca{sup 2+}, Sr{sup 2+} and PO{sub 4}{sup 3-} ions that migrate from the TiO{sub 2}. These Sr-HA nanofibers construct a network structure similar to the hierarchical organization of bone extracellular matrix (ECM), and the resulting nanofibrous surface displays a firm adhesion to substrate, superhydrophilicity and apatite-inducing ability. The induced apatite prefers to nucleate on the basal-faceted surfaces of Sr-HA nanofibers. The nanofiber-walled scaffold has a great potential for load-bearing orthotopic use.

  17. A multi-scaled hybrid orthopedic implant: bone ECM-shaped Sr-HA nanofibers on the microporous walls of a macroporous titanium scaffold.

    Science.gov (United States)

    Han, Yong; Zhou, Jianhong; Zhang, Lan; Xu, Kewei

    2011-07-08

    We report here, for the first time, a novel multi-scaled hybrid orthopedic implant material consisting of a macroporous Ti scaffold, whose macropores' walls have a microporous titania layer which is fully covered with nanofibers of Sr-doped hydroxyapatite (Sr-HA). The microporous titania layer is formed on and within the Ti scaffold by micro-arc oxidation, which firmly binds to the Ti substrate and contains Ca2+, Sr2+ and PO4(3-) ions. It is then hydrothermally treated to form Sr-HA nanofibers. During the hydrothermal treatment, Sr-HA nanoprisms nucleate from Ca0.5Sr0.5TiO3 pre-formed on the TiO2 and grow in length to nanofibers at the expense of Ca2+, Sr2+ and PO4(3-) ions that migrate from the TiO2. These Sr-HA nanofibers construct a network structure similar to the hierarchical organization of bone extracellular matrix (ECM), and the resulting nanofibrous surface displays a firm adhesion to substrate, superhydrophilicity and apatite-inducing ability. The induced apatite prefers to nucleate on the basal-faceted surfaces of Sr-HA nanofibers. The nanofiber-walled scaffold has a great potential for load-bearing orthotopic use.

  18. Hybrid matrices of TiO2 and TiO2–Ag nanofibers with silicone for high water flux photocatalytic degradation of dairy effluent

    DEFF Research Database (Denmark)

    Kanjwal, Muzafar Ahmad; Alm, Martin; Thomsen, Peter

    2016-01-01

    TiO2 and TiO2–Ag nanofibers were produced by electrospinning technique and surface coated on silicone elastomer (diameter: 10.0 mm; thickness: 2.0 mm) by dipcoating method. These coated hybrid nanoporous matrices were characterized by various morphological and physicochemical techniques (like SEM...

  19. A hybrid nanostructure of platinum-nanoparticles/graphitic-nanofibers as a three-dimensional counter electrode in dye-sensitized solar cells.

    Science.gov (United States)

    Hsieh, Chien-Kuo; Tsai, Ming-Chi; Su, Ching-Yuan; Wei, Sung-Yen; Yen, Ming-Yu; Ma, Chen-Chi M; Chen, Fu-Rong; Tsai, Chuen-Horng

    2011-11-07

    We directly synthesized a platinum-nanoparticles/graphitic-nanofibers (PtNPs/GNFs) hybrid nanostructure on FTO glass. We applied this structure as a three-dimensional counter electrode in dye-sensitized solar cells (DSSCs), and investigated the cells' photoconversion performance. This journal is © The Royal Society of Chemistry 2011

  20. Electrospun Fe3O4/TiO2 hybrid nanofibers and their in vitro biocompatibility: prospective matrix for satellite cell adhesion and cultivation.

    Science.gov (United States)

    Amna, Touseef; Hassan, M Shamshi; Van Ba, Hoa; Khil, Myung-Seob; Lee, Hak-Kyo; Hwang, I H

    2013-03-01

    We report the fabrication of novel Fe3O4/TiO2 hybrid nanofibers with the improved cellular response for potential tissue engineering applications. In this study, Fe3O4/TiO2 hybrid nanofibers were prepared by facile sol-gel electrospinning using titanium isopropoxide and iron(III) nitrate nonahydrate as precursors. The obtained electrospun nanofibers were vacuum dried at 80 °C and then calcined at 500 °C. The physicochemical characterization of the synthesized composite nanofibers was carried out by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray diffraction pattern. To examine the in vitro cytotoxicity, satellite cells were treated with as-prepared Fe3O4/TiO2 and the viability of cells was analyzed by Cell Counting Kit-8 assay at regular time intervals. The morphological features of unexposed satellite cells and exposed to Fe3O4/TiO2 composite were examined with a phase contrast microscope whereas the quantification of cell viability was carried out via confocal laser scanning microscopy. The morphology of the cells attached to hybrid matrix was observed by Bio-SEM. Cytotoxicity experiments indicated that the satellite cells could attach to the Fe3O4/TiO2 composite nanofibers after being cultured. We observed that Fe3O4-TiO2 composite nanofibers could support cell adhesion and growth. Results from this study therefore suggest that Fe3O4/TiO2 composite scaffold with small diameters (approximately 200 nm) can mimic the natural extracellular matrix well and provide possibilities for diverse applications in the field of tissue engineering and regenerative medicine. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Lower hybrid drift instability in modified Harris current sheet with negative ions

    International Nuclear Information System (INIS)

    Huang Feng; Chen, Y-H; Shi Guifen; Hu, Z-Q; Yu, M Y

    2008-01-01

    The lower hybrid drift instability (LHDI) in a Harris current sheet with negative ions is investigated using the kinetic theory. Numerical results show that the negative ions have considerable effect on the LHDI. With increase of the negative-ion concentration, the growth rate of the LHDI increases and its real frequency decreases for any wave length. The Harris current sheet can thus be significantly modified

  2. Electrospun Fe3O4/TiO2 hybrid nanofibers and their in vitro biocompatibility: Prospective matrix for satellite cell adhesion and cultivation

    International Nuclear Information System (INIS)

    Amna, Touseef; Hassan, M. Shamshi; Van Ba, Hoa; Khil, Myung-Seob; Lee, Hak-Kyo; Hwang, I.H.

    2013-01-01

    We report the fabrication of novel Fe 3 O 4 /TiO 2 hybrid nanofibers with the improved cellular response for potential tissue engineering applications. In this study, Fe 3 O 4 /TiO 2 hybrid nanofibers were prepared by facile sol–gel electrospinning using titanium isopropoxide and iron(III) nitrate nonahydrate as precursors. The obtained electrospun nanofibers were vacuum dried at 80 °C and then calcined at 500 °C. The physicochemical characterization of the synthesized composite nanofibers was carried out by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray diffraction pattern. To examine the in vitro cytotoxicity, satellite cells were treated with as-prepared Fe 3 O 4 /TiO 2 and the viability of cells was analyzed by Cell Counting Kit-8 assay at regular time intervals. The morphological features of unexposed satellite cells and exposed to Fe 3 O 4 /TiO 2 composite were examined with a phase contrast microscope whereas the quantification of cell viability was carried out via confocal laser scanning microscopy. The morphology of the cells attached to hybrid matrix was observed by Bio-SEM. Cytotoxicity experiments indicated that the satellite cells could attach to the Fe 3 O 4 /TiO 2 composite nanofibers after being cultured. We observed that Fe 3 O 4 –TiO 2 composite nanofibers could support cell adhesion and growth. Results from this study therefore suggest that Fe 3 O 4 /TiO 2 composite scaffold with small diameters (approximately 200 nm) can mimic the natural extracellular matrix well and provide possibilities for diverse applications in the field of tissue engineering and regenerative medicine. Highlights: ► We report fabrication of novel Fe 3 O 4 /TiO 2 hybrid nanofibers by facile electrospinning. ► The utilized satellite cells were isolated from native Korean Hanwoo cattle. ► Fe 3 O 4 /TiO 2 composite with small diameters (∼ 200 nm) can mimic the natural ECM well. ► Fe 3 O 4 /TiO 2

  3. Hepatocyte growth on polycapronolactone and 2-hydroxyethylmethacrylate nanofiber sheets enhanced by bone marrow-derived mesenchymal stromal cells

    Czech Academy of Sciences Publication Activity Database

    Mareková, Dana; Lesný, Petr; Jendelová, Pavla; Michálek, Jiří; Kostecká, Petra; Přádný, Martin; Martinová, L.; Pantoflíček, T.; Ryska, M.; Syková, Eva

    2013-01-01

    Roč. 60, č. 125 (2013), s. 1156-1163 ISSN 0172-6390 R&D Projects: GA ČR GA304/07/1129; GA AV ČR KAN200520804; GA MŠk 1M0538 Institutional research plan: CEZ:AV0Z50390703 Institutional support: RVO:61389013 ; RVO:68378041 Keywords : nanofibers * hepatocytes * Bioartificial Liver Assist Device Subject RIV: FH - Neurology Impact factor: 0.907, year: 2013

  4. Nucleation and Growth of Ordered Arrays of Silver Nanoparticles on Peptide Nanofibers: Hybrid Nanostructures with Antimicrobial Properties.

    Science.gov (United States)

    Pazos, Elena; Sleep, Eduard; Rubert Pérez, Charles M; Lee, Sungsoo S; Tantakitti, Faifan; Stupp, Samuel I

    2016-05-04

    Silver nanoparticles have been of great interest as plasmonic substrates for sensing and imaging, catalysts, or antimicrobial systems. Their physical properties are strongly dependent on parameters that remain challenging to control such as size, chemical composition, and spatial distribution. We report here on supramolecular assemblies of a novel peptide amphiphile containing aldehyde functionality in order to reduce silver ions and subsequently nucleate silver metal nanoparticles in water. This system spontaneously generates monodisperse silver particles at fairly regular distances along the length of the filamentous organic assemblies. The metal-organic hybrid structures exhibited antimicrobial activity and significantly less toxicity toward eukaryotic cells. Metallized organic nanofibers of the type described here offer the possibility to create hydrogels, which integrate the useful functions of silver nanoparticles with controllable metallic content.

  5. Highly efficient hybrid energy generator: coupled organic photovoltaic device and randomly oriented electrospun poly(vinylidene fluoride) nanofiber.

    Science.gov (United States)

    Park, Boongik; Lee, Kihwan; Park, Jongjin; Kim, Jongmin; Kim, Ohyun

    2013-03-01

    A hybrid architecture consisting of an inverted organic photovoltaic device and a randomly-oriented electrospun PVDF piezoelectric device was fabricated as a highly-efficient energy generator. It uses the inverted photovoltaic device with coupled electrospun PVDF nanofibers as tandem structure to convert solar and mechanical vibrations energy to electricity simultaneously or individually. The power conversion efficiency of the photovoltaic device was also significantly improved up to 4.72% by optimized processes such as intrinsic ZnO, MoO3 and active layer. A simple electrospinning method with the two electrode technique was adopted to achieve a high voltage of - 300 mV in PVDF piezoelectric fibers. Highly-efficient HEG using voltage adder circuit provides the conceptual possibility of realizing multi-functional energy generator whenever and wherever various energy sources are available.

  6. Local sustained delivery of acetylsalicylic acid via hybrid stent with biodegradable nanofibers reduces adhesion of blood cells and promotes reendothelialization of the denuded artery

    Directory of Open Access Journals (Sweden)

    Lee CH

    2014-01-01

    Full Text Available Cheng-Hung Lee,1,2 Yu-Huang Lin,3 Shang-Hung Chang,1 Chun-Der Tai,3 Shih-Jung Liu,2 Yen Chu,4 Chao-Jan Wang,5 Ming-Yi Hsu,5 Hung Chang,6 Gwo-Jyh Chang,7 Kuo-Chun Hung,1 Ming-Jer Hsieh,1 Fen-Chiung Lin,1 I-Chang Hsieh,1 Ming-Shien Wen,1 Yenlin Huang81Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, 2Department of Mechanical Engineering, 3Graduate Institute of Medical Mechatronics, Chang Gung University, 4Laboratory of Cardiovascular Physiology, Division of Thoracic and Cardiovascular Surgery, 5Department of Medical Imaging and Intervention, 6Hematology-Oncology Division, Department of Internal Medicine, Chang Gung Memorial Hospital, Linkou, 7Graduate Institute of Clinical Medicinal Sciences, Chang Gung University College of Medicine, Linkou, 8Department of Anatomical Pathology, Chang Gung Memorial Hospital, Linkou, Tao-Yuan, TaiwanAbstract: Incomplete endothelialization, blood cell adhesion to vascular stents, and inflammation of arteries can result in acute stent thromboses. The systemic administration of acetylsalicylic acid decreases endothelial dysfunction, potentially reducing thrombus, enhancing vasodilatation, and inhibiting the progression of atherosclerosis; but, this is weakened by upper gastrointestinal bleeding. This study proposes a hybrid stent with biodegradable nanofibers, for the local, sustained delivery of acetylsalicylic acid to injured artery walls. Biodegradable nanofibers are prepared by first dissolving poly(D,L-lactide-co-glycolide and acetylsalicylic acid in 1,1,1,3,3,3-hexafluoro-2-propanol. The solution is then electrospun into nanofibrous tubes, which are then mounted onto commercially available bare-metal stents. In vitro release rates of pharmaceuticals from nanofibers are characterized using an elution method, and a high-performance liquid chromatography assay. The experimental results suggest that biodegradable nanofibers

  7. Hedging Life and Pension Company Balance Sheets with Hybrid Derivatives

    DEFF Research Database (Denmark)

    Jørgensen, Peter Løchte

    2009-01-01

    Life and Pension companies are facing enhanced risks of market due to dynamic interest rates and unprecedented volatility in equities, jeopardising guarantee of performance to policyholders and shareholders. Evolving statutory requirements and financial reporting standards, add to the challenges...... for these companies. This paper highlights the utility of "Hybrid Derivatives" and the new risk based solvency reporting system, know as "Traffic Light System" adopted by the Danish Financial Supervisory Authority, as an answer to the challenges posed....

  8. Upper Hybrid Resonance of Microwaves with a Large Magnetized Plasma Sheet

    International Nuclear Information System (INIS)

    Huo Wenqing; Guo Shijie; Ding Liang; Xu Yuemin

    2013-01-01

    A large magnetized plasma sheet with size of 60 cm × 60 cm × 2 cm was generated by a linear hollow cathode discharge under the confinement of a uniform magnetic field generated by a Helmholtz Coil. The microwave transmission characteristic of the plasma sheet was measured for different incident frequencies, in cases with the electric field polarization of the incident microwave either perpendicular or parallel to the magnetic field. In this measurement, parameters of the plasma sheet were changed by varying the discharge current and magnetic field intensity. In the experiment, upper hybrid resonance phenomena were observed when the electric field polarization of the incident wave was perpendicular to the magnetic field. These resonance phenomena cannot be found in the case of parallel polarization incidence. This result is consistent with theoretical consideration. According to the resonance condition, the electron density values at the resonance points are calculated under various experimental conditions. This kind of resonance phenomena can be used to develop a specific method to diagnose the electron density of this magnetized plasma sheet apparatus. Moreover, it is pointed out that the operating parameters of the large plasma sheet in practical applications should be selected to keep away from the upper hybrid resonance point to prevent signals from polarization distortion

  9. Electrical bistability in conductive hybrid composites of doped polyaniline nanofibers-gold nanoparticles capped with dodecane thiol.

    Science.gov (United States)

    Borriello, A; Agoretti, P; Cassinese, A; D'Angelo, P; Mohanraj, G T; Sanguigno, L

    2009-11-01

    A novel electrical bistable hybrid nanocomposite based on doped Polyaniline nanofibers with 1-Dodecanethiol-protected Gold nanoparticle (PAni.AuDT), 3-4 nm in size, as the conductive component and polystyrene as polymer matrix was prepared. The structural morphology of the composite and the dispersion of nanoparticles inside it were evaluated using Transmission Electron Microscopy (TEM). The thermal stability and the ratio Polyaniline/Gold nanoparticles in the composite were determined by using thermogravimetric analysis. The electrical bistability of the PAni.AuDT-PS composite, the influence of the dispersion of the PAni.AuDT conductive network and the basic operation mechanism, have been assessed by measuring the electrical response of planar device architectures, also as a function of the environmental temperature (in the range 200 K K). The basic operation mechanism of the hybrid compound has been then correlated to the combined action of the thermally-induced scattering of charge carriers and the thermal contraction of the hosting polymeric matrix. Moreover, the right compromise between these two effects in terms of the most efficient bistability has been studied, founding the concentration of the conductive component which optimizes the device on-off ratio (I(on)/ I(off)).

  10. Studying the Properties of Polyvinyl Alcohol/Cellulose Nanofiber/Hydroxyapatite Hybrid Nanocomposite

    Directory of Open Access Journals (Sweden)

    Mostafa Yahyavi

    2015-06-01

    Full Text Available Nanocomposite materials have recently attracted much attention because of their desirable and unique physical and mechanical properties. Today, many studies have focused on the preparation of high performance new nanocomposites made of biobased and biodegradable materials as both the matrix and reinforcement phases. Because of biocompatibility, biofunctionality, and biological safety in the body, hydroxyapatite-polyvinyl alcohol composites are vastly used in medical applications, specially in the bone tissue regeneration. The properties of a new generation of nanocomposites consisting of hydroxyapatite nanoparticles and cellulose nanofibers, dispersed in polyvinyl alcohol matrix, were investigated. The percentage by weight of each component in the final formulation and the time of ultrasonication were studied as factors affecting the physical and mechanical properties. Tensile strength, elastic modulus and resistance to water dissolution were evaluated. The results showed that by increasing the percentage by weight of PVA and cellulose nanofibers and ultrasonication time, the tensile strength and elastic modulus increased and the resistance to water dissolution and weight loss decreased. On the other hand, with increasing the amount of hydroxyapatite nanoparticles in the final formulation, the elastic modulus and resistance to water solubility increased, while the tensile strength decreased significantly. Scanning electron microscopy (SEM micrographs were used to find exact correlations between the observed physical and mechanical properties and the structural morphology.

  11. Controllable preparation of multi-dimensional hybrid materials of nickel-cobalt layered double hydroxide nanorods/nanosheets on electrospun carbon nanofibers for high-performance supercapacitors

    International Nuclear Information System (INIS)

    Lai, Feili; Huang, Yunpeng; Miao, Yue-E; Liu, Tianxi

    2015-01-01

    Graphical Abstract: Multi-dimensional hybrid materials of nickel-cobalt layered double hydroxide nanorods/nanosheets grown on electrospun carbon nanofiber membranes were prepared via electrospinning combined with solution co-deposition for high-performance supercapacitor electrodes. - Highlights: • Ni-Co LDH@CNFhybridswerepreparedbyelectrospinningandsolutionco-deposition. • Ni-Co LDH@CNF hybrids show high electrochemical performance for supercapacitors. • This method can be extended to other bimetallic@CNF hybrids for electrode materials. - Abstract: Hybrid nanomaterials with hierarchical structures have been considered as one kind of the most promising electrode materials for high-performance supercapacitors with high capacity and long cycle lifetime. In this work, multi-dimensional hybrid materials of nickel-cobalt layered double hydroxide (Ni-Co LDH) nanorods/nanosheets on carbon nanofibers (CNFs) were prepared by electrospinning technique combined with one-step solution co-deposition method. Carbon nanofiber membranes were obtained by electrospinning of polyacrylonitrile (PAN) followed by pre-oxidation and carbonization. The successful growth of Ni-Co LDH with different morphologies on CNF membrane by using two kinds of auxiliary agents reveals the simplicity and universality of this method. The uniform and immense growth of Ni-Co LDH on CNFs significantly improves its dispersion and distribution. Meanwhile the hierarchical structure of carbon nanofiber@nickel-cobalt layered double hydroxide nanorods/nanosheets (CNF@Ni-Co LDH NR/NS) hybrid membranes provide not only more active sites for electrochemical reaction but also more efficient pathways for electron transport. Galvanostatic charge-discharge measurements reveal high specific capacitances of 1378.2 F g −1 and 1195.4 F g −1 (based on Ni-Co LDH mass) at 1 A g −1 for CNF@Ni-Co LDH NR and CNF@Ni-Co LDH NS hybrid membranes, respectively. Moreover, cycling stabilities for both hybrid membranes are

  12. Algae decorated TiO2/Ag hybrid nanofiber membrane with enhanced photocatalytic activity for Cr(VI) removal under visible light

    OpenAIRE

    Wang, L; Zhang, C; Gao, F; Mailhot, G; Pan, G

    2017-01-01

    Algae as an abundant natural biomass, more attention has been paid to explore its potential application in environmental pollutants treatment. This work prepared the algae-TiO2/Ag bionano hybrid material by loading algae cells on the ultrafine TiO2/Ag chitosan hybrid nanofiber mat. For the first time, the synergistic photocatalytic effect of fresh algae and TiO2/Ag nanomaterial was investigated by removal of Cr(VI). The addition of algae significantly improved the photo-removal of Cr(VI) in t...

  13. Impulse Hydroforming Method for Very Thin Sheets from Metallic or Hybrid Materials

    OpenAIRE

    Beerwald, C.; Beerwald, M.; Dirksen, U.; Henselek, A.

    2010-01-01

    Forming of very thin metallic and hybrid material foils is a demanding task in several application areas as for example in food or pharmaceutical packaging industries. Narrow forming limits of very thin sheet metals as well as minor process reliability due to necessary exact tool manufacturing (small punch-die clearance), both, causes abiding interest in new and innovative forming processes. In this contribution a new method using high pressure pulses will be introduced to form small geometry...

  14. Generalized lower-hybrid drift instabilities in current-sheet equilibrium

    International Nuclear Information System (INIS)

    Yoon, Peter H.; Lui, Anthony T. Y.; Sitnov, Mikhail I.

    2002-01-01

    A class of drift instabilities in one-dimensional current-sheet configuration, i.e., classical Harris equilibrium, with frequency ranging from low ion-cyclotron to intermediate lower-hybrid frequencies, are investigated with an emphasis placed on perturbations propagating along the direction of cross-field current flow. Nonlocal two-fluid stability analysis is carried out, and a class of unstable modes with multiple eigenstates, similar to that of the familiar quantum mechanical potential-well problem, are found by numerical means. It is found that the most unstable modes correspond to quasi-electrostatic, short-wavelength perturbations in the lower-hybrid frequency range, with wave functions localized at the edge of the current sheet where the density gradient is maximum. It is also found that there exist quasi-electromagnetic modes located near the center of the current sheet where the current density is maximum, with both kink- and sausage-type polarizations. These modes are low-frequency, long-wavelength perturbations. It turns out that the current-driven modes are low-order eigensolutions while the lower-hybrid-type modes are higher-order states, and there are intermediate solutions between the two extreme cases. Attempts are made to interpret the available simulation results in light of the present eigenmode analysis

  15. Drug loaded homogeneous electrospun PCL/gelatin hybrid nanofiber structures for anti-infective tissue regeneration membranes.

    Science.gov (United States)

    Xue, Jiajia; He, Min; Liu, Hao; Niu, Yuzhao; Crawford, Aileen; Coates, Phil D; Chen, Dafu; Shi, Rui; Zhang, Liqun

    2014-11-01

    Infection is the major reason for guided tissue regeneration/guided bone regeneration (GTR/GBR) membrane failure in clinical application. In this work, we developed GTR/GBR membranes with localized drug delivery function to prevent infection by electrospinning of poly(ε-caprolactone) (PCL) and gelatin blended with metronidazole (MNA). Acetic acid (HAc) was introduced to improve the miscibility of PCL and gelatin to fabricate homogeneous hybrid nanofiber membranes. The effects of the addition of HAc and the MNA content (0, 1, 5, 10, 20, 30, and 40 wt.% of polymer) on the properties of the membranes were investigated. The membranes showed good mechanical properties, appropriate biodegradation rate and barrier function. The controlled and sustained release of MNA from the membranes significantly prevented the colonization of anaerobic bacteria. Cells could adhere to and proliferate on the membranes without cytotoxicity until the MNA content reached 30%. Subcutaneous implantation in rabbits for 8 months demonstrated that MNA-loaded membranes evoked a less severe inflammatory response depending on the dose of MNA than bare membranes. The biodegradation time of the membranes was appropriate for tissue regeneration. These results indicated the potential for using MNA-loaded PCL/gelatin electrospun membranes as anti-infective GTR/GBR membranes to optimize clinical application of GTR/GBR strategies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Enhancement of chondrogenic differentiation of rabbit mesenchymal stem cells by oriented nanofiber yarn-collagen type I/hyaluronate hybrid

    International Nuclear Information System (INIS)

    Zheng, Xianyou; Wang, Wei; Liu, Shen; Wu, Jinglei; Li, Fengfeng; Cao, Lei; Liu, Xu-dong; Mo, Xiumei; Fan, Cunyi

    2016-01-01

    Cartilage defects cause joint pain and loss of mobility. It is crucial to induce the chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) by both biological and structural signals in cartilage tissue engineering. Sponge-like scaffolds fabricated using native cartilage extracellular matrix components can induce the BMSC differentiation by biological signals and limited structural signals. In this study, an oriented poly(L-lactic acid)-co-poly(ε-caprolactone) P(LLA-CL)/collagen type I (Col-I) nanofiber yarn mesh, fabricated by dynamic liquid electrospinning served as a skeleton for a freeze-dried Col-I/hyaluronate (HA) chondral phase (SPONGE) containing both structural and biological signals to guide BMSC chondrogenic differentiation. In vitro results show that the Yarn Col-I/HA hybrid scaffold (Yarn-CH) promotes orientation, adhesion and proliferation of BMSCs better than SPONGE. Furthermore, BMSCs seeded on the Yarn-CH scaffold demonstrated a large increase in the glycosaminoglycan content and expression of collagen type II following a 21-day culture. - Highlights: • An oriented yarn was used as the skeleton of the sponge-like scaffold. • Both structural and biological signals were given for BMSC chondrogenic differentiation. • Yarn-CH promotes orientation and chondrogenesis differentiation of BMSCs. • Yarn-CH reproduces the superficial zone of the cartilage.

  17. Osteogenesis of human adipose-derived stem cells on hydroxyapatite-mineralized poly(lactic acid) nanofiber sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kung, Fu-Chen [Department of Health Developing and Health Marketing, Kainan University, Taiwan (China); Lin, Chi-Chang, E-mail: chichang31@thu.edu.tw [Department of Chemical and Materials Engineering, Tunghai University, Taiwan (China); Lai, Wen-Fu T., E-mail: Laitw@tmu.edu.tw [Graduate Institute of Clinical Medicine, Taipei Medical University, Taiwan (China)

    2014-12-01

    Electrospun fiber sheets with various orientations (random, partially aligned, and aligned) and smooth and roughened casted membranes were prepared. Hydroxyapatite (HA) crystals were in situ formed on these material surfaces via immersion in 10 × simulated body fluid solution. The size and morphology of the resulting fibers were examined using scanning electron microscopy. The average diameter of the fibers ranged from 225 ± 25 to 1050 ± 150 nm depending on the electrospinning parameters. Biological experiment results show that human adipose-derived stem cells exhibit different adhesion and osteogenic differentiation on the three types of fiber. The cell proliferation and osteogenic differentiation were best on the aligned fibers. Similar results were found for phosphorylated focal adhesion kinase expression. Electrospun poly(lactic acid) aligned fibers mineralized with HA crystals provide a good environment for cell growth and osteogenic differentiation and thus have great potential in the tissue engineering field. - Highlights: • hADSCs show higher adhesion and proliferation on HA-precipitate electrospun fiber sheets than those of the control membranes. • HA-mineralized fiber groups greatly improve cell growth and increase FAK and p-FAK expressions. • HA-precipitate electrospun fiber sheets present higher ALP and OC activity through the study periods. • Electrospun PLA fiber mineralized with HA provides a good environment for cell growth and osteogenic differentiation. • A simple immersion of electrospun fibers in 10 × SBF are a potential matrix for bone tissue engineering.

  18. Nano/micro hybrid scaffold of PCL or P3HB nanofibers combined with silk fibroin for tendon and ligament tissue engineering.

    Science.gov (United States)

    Naghashzargar, Elham; Farè, Silvia; Catto, Valentina; Bertoldi, Serena; Semnani, Dariush; Karbasi, Saeed; Tanzi, Maria Cristina

    2015-07-04

    A novel biodegradable nano/micro hybrid structure was obtained by electrospinning P3HB or PCL nanofibers onto a twisted silk fibroin (SF) structure, with the aim of fabricating a suitable scaffold for tendon and ligament tissue engineering. The electrospinning (ES) processing parameters for P3HB and PCL were optimized on 2D samples, and applied to produce two different nano/micro hybrid constructs (SF/ES-PCL and SF/ES-P3HB).Morphological, chemico-physical and mechanical properties of the novel hybrid scaffolds were evaluated by SEM, ATR FT-IR, DSC, tensile and thermodynamic mechanical tests. The results demonstrated that the nanofibers were tightly wrapped around the silk filaments, and the crystallinity of the SF twisted yarns was not influenced by the presence of the electrospun polymers. The slightly higher mechanical properties of the hybrid constructs confirmed an increase of internal forces due to the interaction between nano and micro components. Cell culture tests with L929 fibroblasts, in the presence of the sample eluates or in direct contact with the hybrid structures, showed no cytotoxic effects and a good level of cytocompatibility of the nano/micro hybrid structures in term of cell viability, particularly at day 1. Cell viability onto the nano/micro hybrid structures decreased from the first to the third day of culture when compared with the control culture plastic, but appeared to be higher when compared with the uncoated SF yarns. Although additional in vitro and in vivo tests are needed, the original fabrication method here described appears promising for scaffolds suitable for tendon and ligament tissue engineering.

  19. Self-diagnosis of structures strengthened with hybrid carbon-fiber-reinforced polymer sheets

    Science.gov (United States)

    Wu, Z. S.; Yang, C. Q.; Harada, T.; Ye, L. P.

    2005-06-01

    The correlation of mechanical and electrical properties of concrete beams strengthened with hybrid carbon-fiber-reinforced polymer (HCFRP) sheets is studied in this paper. Two types of concrete beams, with and without reinforcing bars, are strengthened with externally bonded HCFRP sheets, which have a self-structural health monitoring function due to the electrical conduction and piezoresistivity of carbon fibers. Parameters investigated include the volume fractions and types of carbon fibers. According to the investigation, it is found that the hybridization of uniaxial HCFRP sheets with several different types of carbon fibers is a viable method for enhancing the mechanical properties and obtaining a built-in damage detection function for concrete structures. The changes in electrical resistance during low strain ranges before the rupture of carbon fibers are generally smaller than 1%. Nevertheless, after the gradual ruptures of carbon fibers, the electrical resistance increases remarkably with the strain in a step-wise manner. For the specimens without reinforcing bars, the electrical behaviors are not stable, especially during the low strain ranges. However, the electrical behaviors of the specimens with reinforcing bars are relatively stable, and the whole range of self-sensing function of the HCFRP-strengthened RC structures has realized the conceptual design of the HCFRP sensing models and is confirmed by the experimental investigations. The relationships between the strain/load and the change in electrical resistance show the potential self-monitoring capacity of HCFRP reinforcements used for strengthening concrete structures.

  20. Graphene oxide/oxidized carbon nanofiber/mineralized hydroxyapatite based hybrid composite for biomedical applications

    Science.gov (United States)

    Murugan, N.; Sundaramurthy, Anandhakumar; Chen, Shen-Ming; Sundramoorthy, Ashok K.

    2017-12-01

    Hydroxyapatite (Ca10(PO4)6(OH)2, HAP), a multi-mineral substituted calcium phosphate is the main mineral component of tooth enamel and bone, has become an important biomaterial for biomedical applications. However, as-synthesized HAP has poor mechanical properties and inferior wear resistance, so it is not suitable to use in bone tissue engineering applications. We report the successful incorporation of oxidized carbon nanofibers (O-CNF) and graphene oxide (GO) into the mineralized hydroxyapatite (M-HAP) which showed excellent mechanical and biological properties. GO improved the high mechanical strength and corrosion protection of the substrate in simulated body fluid (SBF) solution and promoted the viability of osteoblasts MG63 cells. As-prepared M-HAP/O-CNF/GO composite showed materials characteristics that similar to natural bone (M-HAP) with high mechanical strength. The resultant M-HAP/O-CNF/GO composite was characterized out by x-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and Fourier-transform infrared spectroscopy (FT-IR), respectively. The mechanical strength of the material was determined by Vicker’s micro-hardness method and it was found that M-HAP/O-CNF/GO (468  ±  4 Hv) composite has superior mechanical properties than M-HAP (330  ±  3 Hv) and M-HAP/GO (425  ±  5 Hv) samples. In addition, antibacterial activity of the composite was studied against Staphylococcus aureus and Escherichia coli. Furthermore, the cell viability of the composite was observed in vitro against osteoblast cells. All these studies confirmed that the M-HAP/O-CNF/GO composite can be considered as potential candidate for dental and orthopedic applications.

  1. Integrated fast assembly of free-standing lithium titanate/carbon nanotube/cellulose nanofiber hybrid network film as flexible paper-electrode for lithium-ion batteries.

    Science.gov (United States)

    Cao, Shaomei; Feng, Xin; Song, Yuanyuan; Xue, Xin; Liu, Hongjiang; Miao, Miao; Fang, Jianhui; Shi, Liyi

    2015-05-27

    A free-standing lithium titanate (Li4Ti5O12)/carbon nanotube/cellulose nanofiber hybrid network film is successfully assembled by using a pressure-controlled aqueous extrusion process, which is highly efficient and easily to scale up from the perspective of disposable and recyclable device production. This hybrid network film used as a lithium-ion battery (LIB) electrode has a dual-layer structure consisting of Li4Ti5O12/carbon nanotube/cellulose nanofiber composites (hereinafter referred to as LTO/CNT/CNF), and carbon nanotube/cellulose nanofiber composites (hereinafter referred to as CNT/CNF). In the heterogeneous fibrous network of the hybrid film, CNF serves simultaneously as building skeleton and a biosourced binder, which substitutes traditional toxic solvents and synthetic polymer binders. Of importance here is that the CNT/CNF layer is used as a lightweight current collector to replace traditional heavy metal foils, which therefore reduces the total mass of the electrode while keeping the same areal loading of active materials. The free-standing network film with high flexibility is easy to handle, and has extremely good conductivity, up to 15.0 S cm(-1). The flexible paper-electrode for LIBs shows very good high rate cycling performance, and the specific charge/discharge capacity values are up to 142 mAh g(-1) even at a current rate of 10 C. On the basis of the mild condition and fast assembly process, a CNF template fulfills multiple functions in the fabrication of paper-electrode for LIBs, which would offer an ever increasing potential for high energy density, low cost, and environmentally friendly flexible electronics.

  2. Springback prediction in sheet metal forming process based on the hybrid SA

    International Nuclear Information System (INIS)

    Guo Yuqin; Jiang Hong; Wang Xiaochun; Li Fuzhu

    2005-01-01

    In terms of the intensive similarity between the sheet metal forming-springback process and that of the annealing of metals, it is suggested that the simulation of the sheet metal forming process is performed with the Nonlinear FEM and the springback prediction is implemented by solving the large-scale combinational optimum problem established on the base of the energy descending and balancing in deformed part. The BFGS-SA hybrid SA approach is proposed to solve this problem and improve the computing efficiency of the traditional SA and its capability of obtaining the global optimum solution. At the same time, the correlative annealing strategies for the SA algorithm are determined in here. By comparing the calculation results of sample part with those of experiment measurement at the specified sections, the rationality of the schedule of springback prediction used and the validity of the BFGS-SA algorithm proposed are verified

  3. Surface plasmons excited by the photoluminescence of organic nanofibers in hybrid plasmonic systems

    DEFF Research Database (Denmark)

    Sobolewska, Elzbieta; Leißner, Till; Jozefowski, Leszek

    2016-01-01

    of the fibers. The experimental findings are complemented via finite-difference time-domain (FDTD) modeling. The presented results lead to a better understanding and control of hybrid-mode systems, which are crucial elements in future low-loss energy transfer devices. © (2016) COPYRIGHT Society of Photo...

  4. Research Update: Polyimide/CaCu3Ti4O12 nanofiber functional hybrid films with improved dielectric properties

    Directory of Open Access Journals (Sweden)

    Yang Yang

    2013-11-01

    Full Text Available This work reports the excellent dielectric properties of polyimide (PI embedded with CaCu3Ti4O12 (CCTO nanofibers. The dielectric behaviors were investigated over a frequency of 100 Hz–1 MHz. It is shown that embedding CCTO nanofibers with high aspect ratio (67 is an effective means to enhance the dielectric permittivity and reduce the percolation threshold. The dielectric permittivity of PI/CCTO nanofiber composites is 85 with 1.5 vol.% loading of filler, also the dielectric loss is only 0.015 at 100 Hz. Monte Carlo simulation was used to investigate the percolation threshold of CCTO nanofibers reinforced polyimide matrix by using excluded volume theory and soft, hard-core models. The results are in good agreement with the percolation theory and the hard-core model can well explain the percolation phenomena in PI/CCTO nanofiber composites. The dielectric properties of the composites will meet the practical requirements for the application in high dielectric constant capacitors and high energy density materials.

  5. Chromate-free Hybrid Coating for Corrosion Protection of Electrogalvanized Steel Sheets

    International Nuclear Information System (INIS)

    Jo, Duhwan; Kwon, Moonjae; Kim, Jongsang

    2012-01-01

    Both electrogalvanized and hot-dip galvanized steel sheets have been finally produced via organic-inorganic surface coating process on the zinc surface to enhance corrosion resistance and afford additional functional properties. Recently, POSCO has been developed a variety of chromate-free coated steels that are widely used in household, construction and automotive applications. New organic-inorganic hybrid coating solutions as chromate alternatives are comprised of surface modified silicate with silane coupling agent and inorganic corrosion inhibitors as an aqueous formulation. In this paper we have prepared new type of hybrid coatings and evaluated quality performances such as corrosion resistance, spot weldability, thermal tolerance, and paint adhesion property etc. The electrogalvanized steels with these coating solutions exhibit good anti-corrosion property compared to those of chromate coated steels. Detailed components composition of coating solutions and experimental results suggest that strong binding between organic-inorganic hybrid coating layer and zinc surface plays a key role in the advanced quality performances

  6. Flexible and freestanding supercapacitor based on nanostructured poly(m-aminophenol)/carbon nanofiber hybrid mats with high energy and power densities

    Science.gov (United States)

    Choudhury, Arup; Dey, Baban; Sinha Mahapatra, Susanta; Kim, Doo-Won; Yang, Kap-Seung; Yang, Duck-Joo

    2018-04-01

    Nanostructured poly(m-aminophenol) (PmAP) coated freestanding carbon nanofiber (CNF) mats were fabricated through simple in situ rapid-mixing polymerization of m-aminophenol in the presence of a CNF mat for flexible solid-state supercapacitors. The surface compositions, morphology and pore structure of the hybrid mats were characterized by using various techniques, e.g., FTIR, Raman, XRD, FE-SEM, TEM, and N2 absorption. The results show that the PmAP nanoparticles were homogeneously deposited on CNF surfaces and formed a thin flexible hybrid mat, which were directly used to made electrodes for electrochemical analysis without using any binders or conductive additives. The electrochemical performances of the hybrid mats were easily tailored by varying the PmAP loading on a hybrid electrode. The PmAP/CNF-10 hybrid electrode with a relatively low PmAP loading (> 42 wt%) showed a high specific capacitance of 325.8 F g-1 and a volumetric capacitance of 273.6 F cm-3 at a current density of 0.5 A g-1, together with a specific capacitance retention of 196.2 F g-1 at 20 A g-1. The PmAP/CNF-10 hybrid electrode showed good cycling stability with 88.2% capacitance retention after 5000 cycles. A maximum energy density of 45.2 Wh kg-1 and power density of 20.4 kW kg-1 were achieved for the PmAP/CNF-10 hybrid electrode. This facile and cost-effective synthesis of a flexible binder-free PmAP/CNF hybrid mat with excellent capacitive performances encourages its possible commercial exploitation.

  7. Lower hybrid drift instability in a current sheet with anisotropic temperature

    International Nuclear Information System (INIS)

    Huang Feng; Liu Guohong; Yan Fei; Deng Yan; Chen Yinhua; Yu, M Y; Chen Hanshuang

    2013-01-01

    The effect of the temperature anisotropy on the lower hybrid drift instability (LHDI) in a current sheet is investigated using local kinetic theory. It is found that the ratio r te of the perpendicular to parallel electron temperatures can significantly affect the instability. In fact, a critical value exists r te = r te * , such that when r te >r te * the LHD waves are unstable if the perpendicular wave vector k y is between two threshold values, and when r te te * the LHD mode is stable for any k y . It is also found that r te * increases and the unstable LHD regime shrinks as the parallel wave vector k z increases. That is, sufficiently low perpendicular electron temperature can stabilize the LHDI, especially that of short parallel wavelength. (paper)

  8. Application of YAG Laser TIG Arc Hybrid Welding to Thin AZ31B Magnesium Alloy Sheet

    Science.gov (United States)

    Kim, Taewon; Kim, Jongcheol; Hasegawa, Yu; Suga, Yasuo

    A magnesium alloy is said to be an ecological material with high ability of recycling and lightweight property. Especially, magnesium alloys are in great demand on account of outstanding material property as a structural material. Under these circumstances, research and development of welding process to join magnesium alloy plates are of great significance for wide industrial application of magnesium. In order to use it as a structure material, the welding technology is very important. TIG arc welding process is the most ordinary process to weld magnesium alloy plates. However, since the heat source by the arc welding process affects the magnesium alloy plates, HAZ of welded joint becomes wide and large distortion often occurs. On the other hand, a laser welding process that has small diameter of heat source seems to be one of the possible means to weld magnesium alloy in view of the qualitative improvement. However, the low boiling point of magnesium generates some weld defects, including porosity and solidification cracking. Furthermore, precise edge preparation is very important in butt-welding by the laser welding process, due to the small laser beam diameter. Laser/arc hybrid welding process that combines the laser beam and the arc is an effective welding process in which these two heat sources influence and assist each other. Using the hybrid welding, a synegistic effect is achievable and the disadvantages of the respective processes can be compensated. In this study, YAG laser/TIG arc hybrid welding of thin magnesium alloy (AZ31B) sheets was investigated. First of all, the effect of the irradiation point and the focal position of laser beam on the quality of a weld were discussed in hybrid welding. Then, it was confirmed that a sound weld bead with sufficient penetration is obtained using appropriate welding conditions. Furthermore, it was made clear that the heat absorption efficiency is improved with the hybrid welding process. Finally, the tensile tests

  9. Sol-gel electrospinning preparation of hybrid carbon silica nanofibers for extracting organophosphorus pesticides prior to analyzing them by gas chromatography-ion mobility spectrometry.

    Science.gov (United States)

    Jafari, Mohammad T; Saraji, Mohammad; Kermani, Mansoure

    2018-07-13

    Carbon-silica hybrid nanofibers as high performance coatings for solid-phase microextraction fibers were used for analyzing some pesticides by using gas chromatography-corona discharge ion mobility spectrometry. To that end, the fibers were prepared by carbonizing sol-gel based on electrospun polyacrylonitrile and tetraethyl orthosilicate nanofibers as carbon and silica precursors, respectively. Different parameters affecting the electrospinning and the extraction processes including spinning distance, voltage, feeding rate, stirring rate, salt concentration, temperature and extraction time were optimized by response surface methodology. The method involved deionized water samples spiked with pesticides at different concentration levels. The calibration curves were linear in the ranges of 0.1-20 and 0.05-20 μg L -1 with determination coefficients (R 2 ) of 0.9976 and 0.9928 for malathion and chlorpyrifos, respectively. The limits of detection of 0.032 and 0.019 μg L -1 and the limits of quantification of 0.1 and 0.05 μg L -1 were found for malathion and chlorpyrifos, respectively. Acceptable reproducibility values were obtained with relative standard deviations (RSD, n = 3) lower than 6 and 15%, for intra-day and inter-day precision, respectively. Finally, the relative recoveries of the proposed method were calculated in the range of 80-111% for real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. An Experimental Study on Hybrid Noncompression CF Bracing and GF Sheet Wrapping Reinforcement Method to Restore Damaged RC Structures

    Directory of Open Access Journals (Sweden)

    Kang Seok Lee

    2015-01-01

    Full Text Available We describe a novel technique for restoration of reinforced concrete (RC structures that have sustained damage during an earthquake. The reinforcement scheme described here is a hybrid seismic retrofitting technique that combines noncompression X-bracing using CF with externally bonded GF sheets to strengthen RC structures that have sustained damage following an earthquake. The GF sheet is used to improve the ductility of columns, and the noncompression CF X-bracing system, which consists of CF bracing and anchors to replace the conventional steel bracing and bolt connections, is used to increase the lateral strength of the framing system. We report seismic restoration capacity, which enables reuse of the damaged RC frames via the hybrid CF X-bracing and GF sheet wrapping system. Cyclic loading tests were carried out to investigate hysteresis of the lateral load-drift relations, as well as the ductility. The GF sheet significantly improved the ductility of columns, resulting in a change in failure mode. The strengthening effect of conventional CF sheets used in columns is not sufficient with respect to lateral strength and stiffness. However, this study results in a significant increase in the strength of the structure due to the use of CF X-bracing and inhibited buckling failure of the bracing. This result can be exploited to develop guidelines for the application of the reinforcement system to restore damaged RC structures.

  11. Hybrid Monolith of Graphene/TEMPO-Oxidized Cellulose Nanofiber as Mechanically Robust, Highly Functional, and Recyclable Adsorbent of Methylene Blue Dye

    Directory of Open Access Journals (Sweden)

    Asif Hussain

    2018-01-01

    Full Text Available Herein we demonstrate first report on fabrication, characterization, and adsorptive appraisal of graphene/cellulose nanofibers (GO/CNFs monolith for methylene blue (MB dye. Series of hybrid monolith (GO/CNFs were assembled via urea assisted self-assembly method. Hybrid materials were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction patterns, Raman spectroscopy, elemental analysis, thermogravimetric curve analysis, specific surface area, surface charge density measurement, and compressional mechanical analysis. It was proposed that strong chemical interaction (mainly hydrogen bonding was responsible for the formation of hybrid assembly. GO/CNFs monolith showed mechanically robust architecture with tunable pore structure and surface properties. GO/CNFs adsorbent could completely remove trace to moderate concentrations of MB dye and follow pseudo-second-order kinetics model. Adsorption isotherm behaviors were found in the following order: Langmuir isotherm > Freundlich isotherm > Temkin isotherm model. Maximum adsorption capacity of 227.27 mg g−1 was achieved which is much higher than reported graphene based monoliths and magnetic adsorbent. Incorporation of nanocellulose follows exponential relationship with dye uptake capacities. High surface charge density and specific surface area were main dye adsorptive mechanism. Regeneration and recycling efficiency was achieved up to four consecutive cycles with cost-effective recollection and zero recontamination of treated water.

  12. Superhydrophobic hybrid membranes by grafting arc-like macromolecular bridges on graphene sheets: Synthesis, characterization and properties

    Science.gov (United States)

    Mo, Zhao-Hua; Luo, Zheng; Huang, Qiang; Deng, Jian-Ping; Wu, Yi-Xian

    2018-05-01

    Grafting single end-tethered polymer chains on the surface of graphene is a conventional way to modify the surface properties of graphene oxide. However, grafting arc-like macromolecular bridges on graphene surfaces has been barely reported. Herein, a novel arc-like polydimethylsiloxane (PDMS) macromolecular bridges grafted graphene sheets (GO-g-Arc PDMS) was successfully synthesized via a confined interface reaction at 90 °C. Both the hydrophilic α- and ω-amino groups of linear hydrophobic NH2-PDMS-NH2 macromolecular chains rapidly reacted with epoxy and carboxyl groups on the surfaces of graphene oxide in water suspension to form arc-like PDMS macromolecular bridges on graphene sheets. The grafting density of arc-like PDMS bridges on graphene sheets can reach up to 0.80 mmol g-1 or 1.32 arc-like bridges per nm2 by this confined interface reaction. The water contact angle (WCA) of the hybrid membrane could be increased with increasing both the grafting density and content of covalent arc-like bridges architecture. The superhydrophobic hybrid membrane with a WCA of 153.4° was prepared by grinding of the above arc-like PDMS bridges grafted graphene hybrid, dispersing in ethanol and filtrating by organic filter membrane. This superhydrophobic hybrid membrane shows good self-cleaning and complete oil-water separation properties, which provides potential applications in anticontamination coating and oil-water separation. To the best of our knowledge, this is the first report on the synthesis of functional hybrid membranes by grafting arc-like PDMS macromolecular bridges on graphene sheets via a confined interface reaction.

  13. Material Behavior Based Hybrid Process for Sheet Draw-Forging Thin Walled Magnesium Alloys

    International Nuclear Information System (INIS)

    Sheng, Z.Q.; Shivpuri, R.

    2005-01-01

    Magnesium alloys are conventionally formed at the elevated temperatures. The thermally improved formability is sensitive to the temperature and strain rate. Due to limitations in forming speeds, tooling strength and narrow processing windows, complex thin walled parts cannot be made by traditional warm drawing or hot forging processes. A hybrid process, which is based on the deformation mechanism of magnesium alloys at the elevated temperature, is proposed that combines warm drawing and hot forging modes to produce an aggressive geometry at acceptable forming speed. The process parameters, such as temperatures, forming speeds etc. are determined by the FEM modeling and simulation. Sensitivity analysis under the constraint of forming limits of Mg alloy sheet material and strength of tooling material is carried out. The proposed approach is demonstrated on a conical geometry with thin walls and with bottom features. Results show that designed geometry can be formed in about 8 seconds, this cannot be formed by conventional forging while around 1000s is required for warm drawing. This process is being further investigated through controlled experiments

  14. A Novel High-Power Battery-Pseudocapacitor Hybrid Based on Fast Lithium Reactions in Silicon Anode and Titanium Dioxide Cathode Coated on Vertically Aligned Carbon Nanofibers

    International Nuclear Information System (INIS)

    Klankowski, Steven A.; Pandey, Gaind P.; Malek, Gary A.; Wu, Judy; Rojeski, Ronald A.; Li, Jun

    2015-01-01

    Highlights: • A unique battery-supercapacitor hybrid has been demonstrated. • Both Si anode and TiO_2 cathode are fabricated in the form of nanocolumnar shells coated on VACNFs. • Hybrid cells achieve stable charge-discharge cycles in the supercapacitor power regime. - Abstract: An electrochemical cell representing a battery-supercapacitor hybrid is demonstrated with a Si anode and a TiO_2 cathode based on Lithium chemistry. Both materials are fabricated as coaxial shells with an oblique nanocolumnar structure anchored on vertical aligned carbon nanofiber arrays. The Li"+ ion transport and electrical connection is greatly enhanced with such nanoporous core-shell architectures, leading to optimal Li storage properties. The full theoretical capacity of the shell materials has been obtained at normal C-rates (C/1 to C/2) for Si (∼3,000 to 3500 mA h g"−"1) and TiO_2 (∼170 mA h g"−"1) half-cells, respectively, with excellent cycling stability. More importantly, much higher rates (up to 4.7C_S_i for Si and 76C_T_i_O_2 for TiO_2) can be applied at relatively small capacity loss, approaching the properties of supercapacitors. The charge-discharge profiles show battery-supercapacitor hybrid features, which are attributed to the short Li"+ diffusion path across the solid materials and the large pseudocapacitive contribution from fast surface reactions. A full cell containing similar volume of Si and TiO_2 shows a high specific energy (103 W h kg"−"1) at low current rates, comparable to a decent battery, and a remarkable specific power (56,000 W kg"−"1) at high current rates, matching the state-of-the-art supercapacitors.

  15. Hairy Graphenes: Wrapping Nanocellulose Nets around Graphene Oxide Sheets.

    Science.gov (United States)

    Xiong, Rui; Kim, Ho Shin; Korolovych, Volodymyr F; Zhang, Shuaidi; Yingling, Yaroslava; Tsukruk, Vladimir V

    2018-04-17

    Constructing advanced functional nanomaterials with pre-designed organized morphologies from low-dimension synthetic and biological components is extremely challenging because of complex inter-component interactions, high-aspect ratios, flexible shapes, crumpling instabilities and limited common wet-chemistry processing conditions. Herein, we report an efficient and universal amphiphilicity-driven assembly strategy to construct "hairy" flexible hybrid nanosheets with the net of 1D cellulose nanofibers (CNFs) conformally wrapped around 2D graphene oxide (GO) monolayers. This interface-driven bio-synthetic assembly is facilitated by variable amphiphilic interfacial balance via tailoring the surface chemistry of flexible GO sheets as controllably pre-oxidized 2D template cores, resulting in individual sheets tightly surrounded by dense conformal nanocellulose network. These nanocellulose-net wrapped GO nanosheets demonstrate extremely high compressive elastic modulus above 180 GPa due to the strong bonding between nanofibers and GO sheets and arrest of the buckling events. This unique mechanical stability far exceeds the compressive instability limits of both individual components, 1D cellulose nanofibers and 2D graphene monolayers. Additionally, the presence of CNF reinforced nanocellulose network significantly enhances the wetting ability of initial hydrophobic reduced GO nanosheets, enabling the long-term stability of CNFs-rGO dispersion and allowing fast water transport combined with high filtration efficiency for CNFs-rGO membranes. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Carbon nanofibers (CNFs) supported cobalt- nickel sulfide (CoNi2S4) nanoparticles hybrid anode for high performance lithium ion capacitor.

    Science.gov (United States)

    Jagadale, Ajay; Zhou, Xuan; Blaisdell, Douglas; Yang, Sen

    2018-01-25

    Lithium ion capacitors possess an ability to bridge the gap between lithium ion battery and supercapacitor. The main concern of fabricating lithium ion capacitors is poor rate capability and cyclic stability of the anode material which uses sluggish faradaic reactions to store an electric charge. Herein, we have fabricated high performance hybrid anode material based on carbon nanofibers (CNFs) and cobalt-nickel sulfide (CoNi 2 S 4 ) nanoparticles via simple electrospinning and electrodeposition methods. Porous and high conducting CNF@CoNi 2 S 4 electrode acts as an expressway network for electronic and ionic diffusion during charging-discharging processes. The effect of anode to cathode mass ratio on the performance has been studied by fabricating lithium ion capacitors with different mass ratios. The surface controlled contribution of CNF@CoNi 2 S 4 electrode was 73% which demonstrates its excellent rate capability. Lithium ion capacitor fabricated with CNF@CoNi 2 S 4 to AC mass ratio of 1:2.6 showed excellent energy density of 85.4 Wh kg -1 with the power density of 150 W kg -1 . Also, even at the high power density of 15 kW kg -1 , the cell provided the energy density of 35 Wh kg -1 . This work offers a new strategy for designing high-performance hybrid anode with the combination of simple and cost effective approaches.

  17. High-rate nano-crystalline Li{sub 4}Ti{sub 5}O{sub 12} attached on carbon nano-fibers for hybrid supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Naoi, Katsuhiko; Isobe, Yusaku; Aoyagi, Shintaro [Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8558 (Japan); Ishimoto, Shuichi [Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8558 (Japan); Nippon Chemi-Con Corporation, 363 Arakawa, Takahagi-shi, Ibaraki 318-8505 (Japan)

    2010-09-15

    A lithium titanate (Li{sub 4}Ti{sub 5}O{sub 12})-based electrode which can operate at unusually high current density (300 C) was developed as negative electrode for hybrid capacitors. The high-rate Li{sub 4}Ti{sub 5}O{sub 12} electrode has a unique nano-structure consisting of unusually small nano-crystalline Li{sub 4}Ti{sub 5}O{sub 12} (ca. 5-20 nm) grafted onto carbon nano-fiber anchors (nc-Li{sub 4}Ti{sub 5}O{sub 12}/CNF). This nano-structured nc-Li{sub 4}Ti{sub 5}O{sub 12}/CNF composite are prepared by simple sol-gel method under ultra-centrifugal force (65,000 N) followed by instantaneous annealing at 900 C for 3 min. A model hybrid capacitor cell consisting of a negative nc-Li{sub 4}Ti{sub 5}O{sub 12}/CNF composite electrode and a positive activated carbon electrode showed high energy density of 40 Wh L{sup -1} and high power density of 7.5 kW L{sup -1} comparable to conventional EDLCs. (author)

  18. Determination of morphology and properties of carbon nanofibers and carbon nanofiber polymer nanocomposites

    Science.gov (United States)

    Lawrence, Joseph G.

    Vapor grown carbon nanofibers which resemble carbon nanotubes in structure and properties, have been extensively manufactured and investigated in recent years. Carbon nanofibers have been used for producing multifunctional materials due to their excellent properties and low cost of production. Since, commercially available vapor grown carbon nanofibers are subjected to different processing and post processing conditions, the morphology and properties of these nanofibers are not well-known. In this study, we focus on the characterization of the morphology and properties of these nanofibers and the polymer nanocomposites made using these nanofibers as reinforcements. The morphology of the nanofibers was studied employing high resolution Transmission Electron Microscopy (TEM) images. The analysis showed that the nanofibers consist primarily of conical nanofibers, but can contain a significant amount of bamboo nanofibers. Most of the conical nanofibers were found to consist of an ordered inner layer and a disordered outer layer, with the cone angle distribution of the inner layers indicating that these cannot have a stacked cone structure but are compatible with a cone-helix structure. Nanofibers that were heat treated to temperatures above 1,500°C undergo a structural transformation with the ordered inner layers changing from a cone-helix structure to a highly ordered multiwall stacked cone structure. Due to the complexity in the structure of these nanofibers, a novel method to study the elastic properties and corresponding morphology of individual nanofibers has been developed combining Atomic Force Microscopy (AFM), TEM and Focused Ion Beam (FIB) technology. Employing the developed method, the elastic modulus of individual nanofibers and their corresponding dimensions and morphology were determined. The dependence of elastic properties on the wall thickness and the orientation of graphene sheets in the nanofibers were studied. The elastic modulus of these

  19. Characterization of Tensile Mechanical Behavior of MSCs/PLCL Hybrid Layered Sheet

    Directory of Open Access Journals (Sweden)

    Azizah Intan Pangesty

    2016-06-01

    Full Text Available A layered construct was developed by combining a porous polymer sheet and a cell sheet as a tissue engineered vascular patch. The primary objective of this study is to investigate the influence of mesenchymal stem cells (MSCs sheet on the tensile mechanical properties of porous poly-(l-lactide-co-ε-caprolactone (PLCL sheet. The porous PLCL sheet was fabricated by the solid-liquid phase separation method and the following freeze-drying method. The MSCs sheet, prepared by the temperature-responsive dish, was then layered on the top of the PLCL sheet and cultured for 2 weeks. During the in vitro study, cellular properties such as cell infiltration, spreading and proliferation were evaluated. Tensile test of the layered construct was performed periodically to characterize the tensile mechanical behavior. The tensile properties were then correlated with the cellular properties to understand the effect of MSCs sheet on the variation of the mechanical behavior during the in vitro study. It was found that MSCs from the cell sheet were able to migrate into the PLCL sheet and actively proliferated into the porous structure then formed a new layer of MSCs on the opposite surface of the PLCL sheet. Mechanical evaluation revealed that the PLCL sheet with MSCs showed enhancement of tensile strength and strain energy density at the first week of culture which is characterized as the effect of MSCs proliferation and its infiltration into the porous structure of the PLCL sheet. New technique was presented to develop tissue engineered patch by combining MSCs sheet and porous PLCL sheet, and it is expected that the layered patch may prolong biomechanical stability when implanted in vivo.

  20. Multidimensional MnO2 nanohair-decorated hybrid multichannel carbon nanofiber as an electrode material for high-performance supercapacitors

    Science.gov (United States)

    Jun, Jaemoon; Lee, Jun Seop; Shin, Dong Hoon; Kim, Sung Gun; Jang, Jyongsik

    2015-09-01

    One-dimensional (1D)-structured nanomaterials represent one of the most attractive candidates for energy-storage systems due to their contribution to design simplicity, fast charge-transportation network, and their allowance for more accessible ion diffusion. In particular, 1D-structured nanomaterials with a highly complex inner-pore configuration enhance functionality by taking advantage of both the hollow and 1D structures. In this study, we report a MnO2 nanohair-decorated, hybrid multichannel carbon nanofiber (Mn_MCNF) fabricated via single-nozzle co-electrospinning of two immiscible polymer solutions, followed by carbonization and redox reactions. With improved ion accessibility, the optimized Mn_MCNF sample (Mn_MCNF_60 corresponding to a reaction duration time of 60 min for optimal MnO2 nanohair growth) exhibited a high specific capacitance of 855 F g-1 and excellent cycling performance with ~87.3% capacitance retention over 5000 cycles.One-dimensional (1D)-structured nanomaterials represent one of the most attractive candidates for energy-storage systems due to their contribution to design simplicity, fast charge-transportation network, and their allowance for more accessible ion diffusion. In particular, 1D-structured nanomaterials with a highly complex inner-pore configuration enhance functionality by taking advantage of both the hollow and 1D structures. In this study, we report a MnO2 nanohair-decorated, hybrid multichannel carbon nanofiber (Mn_MCNF) fabricated via single-nozzle co-electrospinning of two immiscible polymer solutions, followed by carbonization and redox reactions. With improved ion accessibility, the optimized Mn_MCNF sample (Mn_MCNF_60 corresponding to a reaction duration time of 60 min for optimal MnO2 nanohair growth) exhibited a high specific capacitance of 855 F g-1 and excellent cycling performance with ~87.3% capacitance retention over 5000 cycles. Electronic supplementary information (ESI) available: Experimental data includes

  1. Superhydrophilic graphene oxide@electrospun cellulose nanofiber hybrid membrane for high-efficiency oil/water separation.

    Science.gov (United States)

    Ao, Chenghong; Yuan, Wei; Zhao, Jiangqi; He, Xu; Zhang, Xiaofang; Li, Qingye; Xia, Tian; Zhang, Wei; Lu, Canhui

    2017-11-01

    Inspired from fishscales, membranes with special surface wettability have been applied widely for the treatment of oily waste water. Herein, a novel superhydrophilic graphene oxide (GO)@electrospun cellulose nanofiber (CNF) membrane was successfully fabricated. This membrane exhibited a high separation efficiency, excellent antifouling properties, as well as a high flux for the gravity-driven oil/water separation. Moreover, the GO@CNF membrane was capable to effectively separate oil/water mixtures in a broad pH range or with a high concentration of salt, suggesting that this membrane was quite promising for future real-world practice in oil spill cleanup and oily wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Mechanical properties and cellular response of novel electrospun nanofibers for ligament tissue engineering: Effects of orientation and geometry.

    Science.gov (United States)

    Pauly, Hannah M; Kelly, Daniel J; Popat, Ketul C; Trujillo, Nathan A; Dunne, Nicholas J; McCarthy, Helen O; Haut Donahue, Tammy L

    2016-08-01

    Electrospun nanofibers are a promising material for ligamentous tissue engineering, however weak mechanical properties of fibers to date have limited their clinical usage. The goal of this work was to modify electrospun nanofibers to create a robust structure that mimics the complex hierarchy of native tendons and ligaments. The scaffolds that were fabricated in this study consisted of either random or aligned nanofibers in flat sheets or rolled nanofiber bundles that mimic the size scale of fascicle units in primarily tensile load bearing soft musculoskeletal tissues. Altering nanofiber orientation and geometry significantly affected mechanical properties; most notably aligned nanofiber sheets had the greatest modulus; 125% higher than that of random nanofiber sheets; and 45% higher than aligned nanofiber bundles. Modifying aligned nanofiber sheets to form aligned nanofiber bundles also resulted in approximately 107% higher yield stresses and 140% higher yield strains. The mechanical properties of aligned nanofiber bundles were in the range of the mechanical properties of the native ACL: modulus=158±32MPa, yield stress=57±23MPa and yield strain=0.38±0.08. Adipose derived stem cells cultured on all surfaces remained viable and proliferated extensively over a 7 day culture period and cells elongated on nanofiber bundles. The results of the study suggest that aligned nanofiber bundles may be useful for ligament and tendon tissue engineering based on their mechanical properties and ability to support cell adhesion, proliferation, and elongation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. N-Doped Porous Carbon Nanofibers/Porous Silver Network Hybrid for High-Rate Supercapacitor Electrode.

    Science.gov (United States)

    Meng, Qingshi; Qin, Kaiqiang; Ma, Liying; He, Chunnian; Liu, Enzuo; He, Fang; Shi, Chunsheng; Li, Qunying; Li, Jiajun; Zhao, Naiqin

    2017-09-13

    A three-dimensional cross-linked porous silver network (PSN) is fabricated by silver mirror reaction using polymer foam as the template. The N-doped porous carbon nanofibers (N-PCNFs) are further prepared on PSN by chemical vapor deposition and treated by ammonia gas subsequently. The PSN substrate serving as the inner current collector will improve the electron transport efficiency significantly. The ammonia gas can not only introduce nitrogen doping into PCNFs but also increase the specific surface area of PCNFs at the same time. Because of its large surface area (801 m 2 /g), high electrical conductivity (211 S/cm), and robust structure, the as-constructed N-PCNFs/PSN demonstrates a specific capacitance of 222 F/g at the current density of 100 A/g with a superior rate capability of 90.8% of its initial capacitance ranging from 1 to 100 A/g while applied as the supercapacitor electrode. The symmetric supercapacitor device based on N-PCNFs/PSN displays an energy density of 8.5 W h/kg with power density of 250 W/kg and excellent cycling stability, which attains 103% capacitance retention after 10 000 charge-discharge cycles at a high current density of 20 A/g, which indicates that N-PCNFs/PSN is a promising candidate for supercapacitor electrode materials.

  4. Production of silk sericin/silk fibroin blend nanofibers

    Directory of Open Access Journals (Sweden)

    Zhang Xianhua

    2011-01-01

    Full Text Available Abstract Silk sericin (SS/silk fibroin (SF blend nanofibers have been produced by electrospinning in a binary SS/SF trifluoroacetic acid (TFA solution system, which was prepared by mixing 20 wt.% SS TFA solution and 10 wt.% SF TFA solution to give different compositions. The diameters of the SS/SF nanofibers ranged from 33 to 837 nm, and they showed a round cross section. The surface of the SS/SF nanofibers was smooth, and the fibers possessed a bead-free structure. The average diameters of the SS/SF (75/25, 50/50, and 25/75 blend nanofibers were much thicker than that of SS and SF nanofibers. The SS/SF (100/0, 75/25, and 50/50 blend nanofibers were easily dissolved in water, while the SS/SF (25/75 and 0/100 blend nanofibers could not be completely dissolved in water. The SS/SF blend nanofibers could not be completely dissolved in methanol. The SS/SF blend nanofibers were characterized by Fourier transform infrared (FTIR spectroscopy, differential scanning calorimetry, and differential thermal analysis. FTIR showed that the SS/SF blend nanofibers possessed a random coil conformation and ß-sheet structure.

  5. Local field enhanced second-harmonic response of organic nanofibers

    DEFF Research Database (Denmark)

    Leißner, Till; Kostiučenko, Oksana; Fiutowski, Jacek

    Organic CNHP4 nanofibers showing a strong second-harmonic (SH) response have been successfully implemented as active components in a metal-organic hybrid system. Using nondestructive roll-on transfer technique nanofibers were transferred from the growing mica substrates onto electron...

  6. Improved fire retardancy of thermoset composites modified with carbon nanofibers

    International Nuclear Information System (INIS)

    Zhao Zhongfu; Gou Jan

    2009-01-01

    Multifunctional thermoset composites were made from polyester resin, glass fiber mats and carbon nanofiber sheets (CNS). Their flaming behavior was investigated with cone calorimeter under well-controlled combustion conditions. The heat release rate was lowered by pre-planting carbon nanofiber sheets on the sample surface with the total fiber content of only 0.38 wt.%. Electron microscopy showed that carbon nanofiber sheet was partly burned and charred materials were formed on the combusting surface. Both the nanofibers and charred materials acted as an excellent insulator and/or mass transport barrier, improving the fire retardancy of the composite. This behavior agrees well with the general mechanism of fire retardancy in various nanoparticle-thermoplastic composites.

  7. Diamond structures grown from polymer composite nanofibers

    Czech Academy of Sciences Publication Activity Database

    Potocký, Štěpán; Kromka, Alexander; Babchenko, Oleg; Rezek, Bohuslav; Martinová, L.; Pokorný, P.

    2013-01-01

    Roč. 5, č. 6 (2013), s. 519-521 ISSN 2164-6627 R&D Projects: GA ČR GAP108/12/0910; GA ČR GAP205/12/0908 Institutional support: RVO:68378271 Keywords : chemical vapour deposition * composite polymer * nanocrystalline diamond * nanofiber sheet * SEM Subject RIV: BM - Solid Matter Physics ; Magnetism

  8. Integrated effect of supramolecular self-assembled sandwich-like melamine cyanurate/MoS{sub 2} hybrid sheets on reducing fire hazards of polyamide 6 composites

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xiaming [State Key Laboratory of Fire Science, University of Science and Technology of China, Anhui 230026 (China); Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou, Jiangsu 215123 (China); Wang, Xin, E-mail: wxcmx@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, Anhui 230026 (China); Cai, Wei; Hong, Ningning [State Key Laboratory of Fire Science, University of Science and Technology of China, Anhui 230026 (China); Hu, Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, Anhui 230026 (China); Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou, Jiangsu 215123 (China); Liew, Kim Meow [Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou, Jiangsu 215123 (China); Department of Architectural and Civil Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

    2016-12-15

    A novel strategy of using supramolecular self-assembly for preparing sandwich-like melamine cyanurate/MoS{sub 2} sheets as the hybrid flame retardants for polyamide 6 (PA6) is reported for the first time. The introduction of MoS{sub 2} sheets function not only as a template to induce the formation of two-dimensional melamine cyanurate capping layers but also as a synergist to generate integrated flame-retarding effect of hybrid sheets, as well as a high-performance smoke suppressor to reduce fire hazards of PA6 materials. Once incorporating this well-designed structures (4 wt%) into PA6 matrix, there resulted in a remarkable drop (40%) in the peak heat release rate and a 25% reduction in total heat release. Moreover, the smoke production and pyrolysis gaseous products were efficiently suppressed by the addition of sandwich-like hybrid sheets. The integrated functions consisting of inherent flame retarding effect, physical barrier performance and catalytic activity are believed to the crucial guarantee for the reduced fire hazards of PA6 nanocomposites. Furthermore, this novel strategy with facile and scalable features may provide reference for developing various kinds of MoS{sub 2} based hybrid sheets for diverse applications.

  9. Hybrid Taxis Give Fuel Economy a Lift, Clean Cities, Fleet Experiences, April 2009 (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2009-04-01

    Clean Cities helped Boston, San Antonio, and Cambridge create hybrid taxi programs. The hybrid taxis are able to achieve about twice the gas mileage of a conventional taxi while helping cut gasoline use and fuel costs. Tax credits and other incentives are helping both company owners and drivers make the switch to hybrids. Program leaders have learned some important lessons other cities can benefit from including learning a city's taxi structure, relaying benefits to drivers, and understanding the needs of owners.

  10. Carbon Supported Engineering NiCo2O4 Hybrid Nanofibers with Enhanced Electrocatalytic Activity for Oxygen Reduction Reaction

    Directory of Open Access Journals (Sweden)

    Diab Hassan

    2016-09-01

    Full Text Available The design of cheap and efficient oxygen reduction reaction (ORR electrocatalysts is of a significant importance in sustainable and renewable energy technologies. Therefore, ORR catalysts with superb electrocatalytic activity and durability are becoming a necessity but still remain challenging. Herein, we report C/NiCo2O4 nanocomposite fibers fabricated by a straightforward electrospinning technique followed by a simple sintering process as a promising ORR electrocatalyst in alkaline condition. The mixed-valence oxide can offer numerous accessible active sites. In addition, the as-obtained C/NiCo2O4 hybrid reveals significantly remarkable electrocatalytic performance with a highly positive onset potential of 0.65 V, which is only 50 mV lower than that of commercially available Pt/C catalysts. The analyses indicate that C/NiCo2O4 catalyst can catalyze O2-molecules via direct four electron pathway in a similar behavior as commercial Pt/C catalysts dose. Compared to single NiCo2O4 and carbon free NiCo2O4, the C/NiCo2O4 hybrid displays higher ORR current and more positive half-wave potential. The incorporated carbon matrices are beneficial for fast electron transfer and can significantly impose an outstanding contribution to the electrocatalytic activity. Results indicate that the synthetic strategy hold a potential as efficient route to fabricate highly active nanostructures for practical use in energy technologies.

  11. Few layered vanadyl phosphate nano sheets-MWCNT hybrid as an electrode material for supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Shibsankar; De, Sukanta, E-mail: sukanta.physics@presiuniv.ac.in [Department of physics, Presidency University, Kolkata-700073 (India)

    2016-05-06

    It have been already seen that 2-dimensional nano materials are the suitable choice for the supercapacitor application due to their large specific surface area, electrochemical active sites, micromechanical flexibility, expedite ion migration channel properties. Free standing hybrid films of functionalized MWCNT (– COOH group) and α-Vanadyl phosphates (VOPO{sub 4}2H{sub 2}O) are prepared by vacuum filtering. The surface morphology and microstructure of the samples are studied by transmission electron microscope, field emission scanning electron microscope, XRD, Electrochemical properties of hybrid films have been investigated systematically in 1M Na{sub 2}SO{sub 4} aqueous electrolyte. The hybrid material exhibits a high specific capacitance 236 F/g with high energy density of 65.6 Wh/Kg and a power density of 1476 W/Kg.

  12. Carbon nanofibers in catalytic membrane microreactors

    NARCIS (Netherlands)

    Aran, H.C.; Pacheco Benito, Sergio; Luiten-Olieman, Maria W.J.; Er, S.; Wessling, Matthias; Lefferts, Leonardus; Benes, Nieck Edwin; Lammertink, Rob G.H.

    2011-01-01

    In this study, we report on the fabrication and operation of new hybrid membrane microreactors for gas–liquid–solid (G–L–S) reactions. The presented reactors consist of porous stainless steel tubes onto which carbon nanofibers (CNFs) are grown as catalyst support, all encapsulated by a gas permeable

  13. Effects of Schwann cell alignment along the oriented electrospun chitosan nanofibers on nerve regeneration.

    Science.gov (United States)

    Wang, Wei; Itoh, Soichiro; Konno, Katsumi; Kikkawa, Takeshi; Ichinose, Shizuko; Sakai, Katsuyoshi; Ohkuma, Tsuneo; Watabe, Kazuhiko

    2009-12-15

    We have constructed a chitosan nonwoven nanofiber mesh tube consisting of oriented fibers by the electrospinning method. The efficacy of oriented nanofibers on Schwann cell alignment and positive effect of this tube on peripheral nerve regeneration were confirmed. The physical properties of the chitosan nanofiber mesh sheets prepared by electrospinning with or without fiber orientation were characterized. Then, immortalized Schwann cells were cultured on these sheets. Furthermore, the chitosan nanofiber mesh tubes with or without orientation, and bilayered chitosan mesh tube with an inner layer of oriented nanofibers and an outer layer of randomized nanofibers were bridgegrafted into rat sciatic nerve defect. As a result of fiber orientation, the tensile strength along the axis of the sheet increased. Because Schwann cells aligned along the nanofibers, oriented fibrous sheets could exhibit a Schwann cell column. Functional recovery and electrophysiological recovery occurred in time in the oriented group as well as in the bilayered group, and approximately matched those in the isograft. Furthermore, histological analysis revealed that the sprouting of myelinated axons occurred vigorously followed by axonal maturation in the isograft, oriented, and bilayered group in the order. The oriented chitosan nanofiber mesh tube may be a promising substitute for autogenous nerve graft.

  14. Cellulose nanofiber extraction from grass by a modified kitchen blender

    Science.gov (United States)

    Nakagaito, Antonio Norio; Ikenaga, Koh; Takagi, Hitoshi

    2015-03-01

    Cellulose nanofibers have been used to reinforce polymers, delivering composites with strength that in some cases can be superior to that of engineering plastics. The extraction of nanofibers from plant fibers can be achieved through specialized equipment that demands high energy input, despite delivering extremely low yields. The high extraction cost confines the use of cellulose nanofibers to the laboratory and not for industrial applications. This study aims to extract nanofibers from grass by using a kitchen blender. Earlier studies have demonstrated that paper sheets made of blender-extracted nanofibers (after 5 min to 10 min of blending) have strengths on par with paper sheets made from commercially available cellulose nanofibers. By optimizing the design of the blender bottle, nanofibrillation can be achieved in shorter treatment times, reducing the energy consumption (in the present case, to half) and the overall extraction cost. The raw materials used can be extended to the residue straw of agricultural crops, as an alternative to the usual pulp fibers obtained from wood.

  15. Highly Transparent and Conductive Metallized Nanofibers by Electrospinning and Electroplating

    Science.gov (United States)

    Yoon, Sam S.; Yarin, Alexander L.

    2017-11-01

    Transparent conducting films (TCFs) and transparent heaters (THs) are of interest for a wide variety of applications, from displays to window defrosters. Here, we demonstrate production of highly flexible, conducting, and transparent copper (Cu), nickel (Ni), platinum (Pt), and silver (Ag) nanofibers suitable for use not only in TCFs and THs but also in some other engineering applications. The merging of fibers at their intersections (i.e. self-junctioning) minimizes contact resistance in these films. These metallized nanofibers exhibited a remarkably low sheet resistance at a high optical transmittance. This low sheet resistance allows them to serve as low-voltage heaters, achieving a high heating temperature at a relatively low applied voltage. These nanofibers are free-standing, flexible, stretchable, and their mechanical reliability was confirmed through various mechanical endurance tests.

  16. Hybrid friction diffusion bonding of 316L stainless steel tube-to-tube sheet joints for coil-wound heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Haneklaus, Nils; Cionea, Cristian; Reuven, Rony; Frazer, David; Hosemann, Peter; Peterson, Per F. [Dept of Nuclear Engineering, University of California, Berkeley (United States)

    2016-11-15

    Hybrid friction diffusion bonding (HFDB) is a solid-state bonding process first introduced by Helmholtz-Zentrum Geesthacht to join aluminum tube-to-tube sheet joints of Coil-wound heat exchangers (CWHE). This study describes how HFDB was successfully used to manufacture 316L test samples simulating tube-to-tube sheet joints of stainless steel CWHE for molten salt coolants as foreseen in several advanced nuclear- and thermal solar power plants. Engineering parameters of the test sample fabrication are presented and results from subsequent non-destructive vacuum decay leak testing and destructive tensile pull-out testing are discussed. The bonded areas of successfully fabricated samples as characterized by tube rupture during pull-out tensile testing, were further investigated using optical microscopy and scanning electron microscopy including electron backscatter diffraction.

  17. Electrospun Gallium Nitride Nanofibers

    International Nuclear Information System (INIS)

    Melendez, Anamaris; Morales, Kristle; Ramos, Idalia; Campo, Eva; Santiago, Jorge J.

    2009-01-01

    The high thermal conductivity and wide bandgap of gallium nitride (GaN) are desirable characteristics in optoelectronics and sensing applications. In comparison to thin films and powders, in the nanofiber morphology the sensitivity of GaN is expected to increase as the exposed area (proportional to the length) increases. In this work we present electrospinning as a novel technique in the fabrication of GaN nanofibers. Electrospinning, invented in the 1930s, is a simple, inexpensive, and rapid technique to produce microscopically long ultrafine fibers. GaN nanofibers are produced using gallium nitrate and dimethyl-acetamide as precursors. After electrospinning, thermal decomposition under an inert atmosphere is used to pyrolyze the polymer. To complete the preparation, the nanofibers are sintered in a tube furnace under a NH 3 flow. Both scanning electron microscopy and profilometry show that the process produces continuous and uniform fibers with diameters ranging from 20 to a few hundred nanometers, and lengths of up to a few centimeters. X-ray diffraction (XRD) analysis shows the development of GaN nanofibers with hexagonal wurtzite structure. Future work includes additional characterization using transmission electron microscopy and XRD to understand the role of precursors and nitridation in nanofiber synthesis, and the use of single nanofibers for the construction of optical and gas sensing devices.

  18. Hollow NiO nanofibers modified by citric acid and the performances as supercapacitor electrode

    International Nuclear Information System (INIS)

    Ren, Bo; Fan, Meiqing; Liu, Qi; Wang, Jun; Song, Dalei; Bai, Xuefeng

    2013-01-01

    Graphical abstract: The possible formation process of NiO nanofibers without citric acid (a), and modified by citric acid (b). When the nanofibers is modified by citric acid, the nickel citrate is produced by complexing action of citric acid and nickel nitrate. Because of the larger space steric hindrance, the structure is limited by the molecular geometry. Under high temperature, the hollow nanofibers composed of NiO slices formed after the removal of PVP. Highlights: ► The method of obtaining hollow nanofibers is raised for the first time. ► The prepared NiO nanofibers are hollow tube and comprised of many NiO sheets. ► The hollow structure facilitated the electrolyte penetration. ► The hollow NiO nanofibers have good electrochemical properties. -- Abstract: NiO nanofibers modified by citric acid (NiO/CA) for supercapacitor material have been fabricated by electrospinning process. The characterizations of the nanofibers are investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. Results show that the NiO/CA nanofibers are hollow tube and comprised of many NiO sheets. Furthermore, the NiO/CA nanofibers have good electrochemical reversibility and display superior capacitive performance with large capacitance (336 F g −1 ), which is 2.5 times of NiO electrodes. Moreover, the NiO/CA nanofibers show excellent cyclic performance after 1000 cycles

  19. Optics of Nanofibers

    DEFF Research Database (Denmark)

    Bordo, Vladimir

    During the last decade, fabrication and investigation of submicron-sized optical fibers have been received growing attention. Such nanofibers or nanowires can be grown from both inorganic and organic semiconductor materials being arranged in mutually parallel nanoaggregates. Also, selected...

  20. Synergistic increase of oxygen reduction favourable Fe-N coordination structures in a ternary hybrid of carbon nanospheres/carbon nanotubes/graphene sheets.

    Science.gov (United States)

    Zhang, Shiming; Liu, Bin; Chen, Shengli

    2013-11-14

    A Fe/N co-doped ternary nanocarbon hybrid, with uniform bamboo-like carbon nanotubes (CNTs) in situ grown on/between the single/few-layer graphene sheets interspaced by carbon nanosphere aggregates, was prepared through a one-pot heat treatment of a precursor mixture containing graphene oxide, Vulcan XC-72 carbon nanospheres, nitrogen rich melamine and small amounts of Fe ions. Physical characterization including electron microscopic images, N2 adsorption-desorption isotherms, pore size distribution, XPS, XRD, Mössbauer spectra, and EDX revealed that the 0-D/1-D/2-D ternary hybrid architecture not only offered an optimized morphology for high dispersion of each nanocarbon moiety, while the carbon nanosphere interspaced graphene sheets have provided a platform for efficient reaction between Fe ions and melamine molecules, resulting in uniform nucleation and growth of CNTs and formation of high density Fe-N coordination assemblies that have been believed to be the active centers for the oxygen reduction reaction (ORR) in carbon-based nonprecious metal electrocatalysts. In the absence of graphene oxides or carbon nanospheres, a similar heat treatment was found to result in large amounts of elemental Fe and Fe carbides and entangled CNTs with wide diameter distributions. As a result, the ternary Fe/N-doped nanocarbon hybrid exhibits ORR activity much higher than the Fe-N doped single or binary nanocarbon materials prepared under similar heat treatment conditions, and approaching that of the state-of-the-art carbon-supported platinum catalyst (Pt/C) in acidic media, as well as superior stability and methanol tolerance to Pt/C.

  1. Low Reflectivity and High Flexibility of Tin-Doped Indium Oxide Nanofiber Transparent Electrodes

    KAUST Repository

    Wu, Hui

    2011-01-12

    Tin-doped indium oxide (ITO) has found widespread use in solar cells, displays, and touch screens as a transparent electrode; however, two major problems with ITO remain: high reflectivity (up to 10%) and insufficient flexibility. Together, these problems severely limit the applications of ITO films for future optoelectronic devices. In this communication, we report the fabrication of ITO nanofiber network transparent electrodes. The nanofiber networks show optical reflectivity as low as 5% and high flexibility; the nanofiber networks can be bent to a radius of 2 mm with negligible changes in the sheet resistance. © 2010 American Chemical Society.

  2. Investigation into Composites Property Effect on the Forming Limits of Multi-Layer Hybrid Sheets Using Hydroforming Technology

    Science.gov (United States)

    Liu, Shichen; Lang, Lihui; Guan, Shiwei; Alexandrov, Seigei; Zeng, Yipan

    2018-04-01

    Fiber-metal laminates (FMLs) such as Kevlar reinforced aluminum laminate (ARALL), Carbon reinforced aluminum laminate (CARALL), and Glass reinforced aluminum laminate (GLARE) offer great potential for weight reduction applications in automobile and aerospace construction. In order to investigate the feasibility for utilizing such materials in the form of laminates, sheet hydroforming technology are studied under the condition of uniform blank holder force for three-layered aluminum and aluminum-composite laminates using orthogonal carbon and Kevlar as well as glass fiber in the middle. The experimental results validate the finite element results and they exhibited that the forming limit of glass fiber in the middle is the highest among the studied materials, while carbon fiber material performs the worst. Furthermore, the crack modes are different for the three kinds of fiber materials investigated in the research. This study provides fundamental guidance for the selection of multi-layer sheet materials in the future manufacturing field.

  3. Effect of Electrospun Nanofibers on the Short Beam Strength of Laminated Fiberglass Composite

    Science.gov (United States)

    Shinde, Dattaji K.

    High specific modulus and strength are the most desirable properties for the material used in structural applications. Composite materials exhibit these properties and over the last decade, their usage has increased significantly, particularly in automotive, defense, and aerospace applications. The major cause of failures in composite laminates is due to delaminations. Delamination in composite laminates can occur due to fatigue, low velocity impact and other loadings modes. Conventional methods like "through-the-thickness stitching" or "Z-Pinning" have limitations for improving flexural and interlaminar properties in woven composites due to the fact that while improving interlaminar properties, the presence of stitches or Z pins affects in-plane properties. This study investigates the flexural behavior of fiberglass composites interleaved with non-woven Tetra Ethyl Orthosilicate (TEOS) electrsopsun nanofibers (ENFs). TEOS ENFs were manufactured using an electrospinning technique and then sintered. Nanoengineered beams were fabricated by interleaving TEOS ENFs between the laminated fiberglass composites to improve the flexural properties. TEOS ENFs, resin film, and failed fiberglass laminated composites with and without nanofibers were characterized using SEM Imaging and ASTM standard testing methods. A hybrid composite was made by interleaving a non-woven sheet of TEOS ENFs between the fiberglass laminates with additional epoxy resin film and fabricated using the out of autoclave vacuum bagging method. Four commonly used stacking sequences of fiberglass laminates with and without nanofibers were used to study the progressive failure and deformation mechanics under flexural loadings. The experimental study has shown significant improvements in short beam strength and strain energy absorption in the nanoengineered laminated fiberglass composites before complete failure. The modes were investigated by performing detailed fractographic examination of failed specimens

  4. Engineering β-sheet peptide assemblies for biomedical applications.

    Science.gov (United States)

    Yu, Zhiqiang; Cai, Zheng; Chen, Qiling; Liu, Menghua; Ye, Ling; Ren, Jiaoyan; Liao, Wenzhen; Liu, Shuwen

    2016-03-01

    Hydrogels have been widely studied in various biomedical applications, such as tissue engineering, cell culture, immunotherapy and vaccines, and drug delivery. Peptide-based nanofibers represent a promising new strategy for current drug delivery approaches and cell carriers for tissue engineering. This review focuses on the recent advances in the use of self-assembling engineered β-sheet peptide assemblies for biomedical applications. The applications of peptide nanofibers in biomedical fields, such as drug delivery, tissue engineering, immunotherapy, and vaccines, are highlighted. The current challenges and future perspectives for self-assembling peptide nanofibers in biomedical applications are discussed.

  5. Nanofiber Filters Eliminate Contaminants

    Science.gov (United States)

    2009-01-01

    With support from Phase I and II SBIR funding from Johnson Space Center, Argonide Corporation of Sanford, Florida tested and developed its proprietary nanofiber water filter media. Capable of removing more than 99.99 percent of dangerous particles like bacteria, viruses, and parasites, the media was incorporated into the company's commercial NanoCeram water filter, an inductee into the Space Foundation's Space Technology Hall of Fame. In addition to its drinking water filters, Argonide now produces large-scale nanofiber filters used as part of the reverse osmosis process for industrial water purification.

  6. High-performance hybrid (electrostatic double-layer and faradaic capacitor-based) polymer actuators incorporating nickel oxide and vapor-grown carbon nanofibers.

    Science.gov (United States)

    Terasawa, Naohiro; Asaka, Kinji

    2014-12-02

    The electrochemical and electromechanical properties of polymeric actuators prepared using nickel peroxide hydrate (NiO2·xH2O) or nickel peroxide anhydride (NiO2)/vapor-grown carbon nanofibers (VGCF)/ionic liquid (IL) electrodes were compared with actuators prepared using solely VGCFs or single-walled carbon nanotubes (SWCNTs) and an IL. The electrode in these actuator systems is equivalent to an electrochemical capacitor (EC) exhibiting both electrostatic double-layer capacitor (EDLC)- and faradaic capacitor (FC)-like behaviors. The capacitance of the metal oxide (NiO2·xH2O or NiO2)/VGCF/IL electrode is primarily attributable to the EDLC mechanism such that, at low frequencies, the strains exhibited by the NiO2·xH2O/VGCF/IL and NiO2/VGCF/IL actuators primarily result from the FC mechanism. The VGCFs in the NiO2·xH2O/VGCF/IL and NiO2/VGCF/IL actuators strengthen the EDLC mechanism and increase the electroconductivity of the devices. The mechanism underlying the functioning of the NiO2·xH2O/VGCF/IL actuator in which NiO2·xH2O/VGCF = 1.0 was found to be different from that of the devices produced using solely VGCFs or SWCNTs, which exhibited only the EDLC mechanism. In addition, it was found that both NiO2 and VGCFs are essential with regard to producing actuators that are capable of exhibiting strain levels greater than those of SWCNT-based polymer actuators and are thus suitable for practical applications. Furthermore, the frequency dependence of the displacement responses of the NiO2·xH2O/VGCF and NiO2/VGCF polymer actuators were successfully simulated using a double-layer charging kinetic model. This model, which accounted for the oxidization and reduction reactions of the metal oxide, can also be applied to SWCNT-based actuators. The results of electromechanical response simulations for the NiO2·xH2O/VGCF and NiO2/VGCF actuators predicted the strains at low frequencies as well as the time constants of the devices, confirming that the model is applicable

  7. Nanomembranes and Nanofibers from Biodegradable Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Jordi Puiggalí

    2013-09-01

    Full Text Available This review provides a current status report of the field concerning preparation of fibrous mats based on biodegradable (e.g., aliphatic polyesters such as polylactide or polycaprolactone and conducting polymers (e.g., polyaniline, polypirrole or polythiophenes. These materials have potential biomedical applications (e.g., tissue engineering or drug delivery systems and can be combined to get free-standing nanomembranes and nanofibers that retain the better properties of their corresponding individual components. Systems based on biodegradable and conducting polymers constitute nowadays one of the most promising solutions to develop advanced materials enable to cover aspects like local stimulation of desired tissue, time controlled drug release and stimulation of either the proliferation or differentiation of various cell types. The first sections of the review are focused on a general overview of conducting and biodegradable polymers most usually employed and the explanation of the most suitable techniques for preparing nanofibers and nanomembranes (i.e., electrospinning and spin coating. Following sections are organized according to the base conducting polymer (e.g., Sections 4–6 describe hybrid systems having aniline, pyrrole and thiophene units, respectively. Each one of these sections includes specific subsections dealing with applications in a nanofiber or nanomembrane form. Finally, miscellaneous systems and concluding remarks are given in the two last sections.

  8. Treated Carbon Nanofibers for Storing Energy in Aqueous KOH

    Science.gov (United States)

    Firsich, David W.

    2004-01-01

    A surface treatment has been found to enhance the performances of carbon nanofibers as electrode materials for electrochemical capacitors in which aqueous solutions of potassium hydroxide are used as the electrolytes. In the treatment, sulfonic acid groups are attached to edge plane sites on carbon atoms. The treatment is applicable to a variety of carbon nanofibers, including fibrils and both single- and multiple-wall nanotubes. The reason for choosing nanofibers over powders and other forms of carbon is that nanofibers offer greater power features. In previous research, it was found that the surface treatment of carbon nanofibers increased energy-storage densities in the presence of acid electrolytes. Now, it has been found that the same treatment increases energy-storage densities of carbon nanofibers in the presence of alkaline electrolytes when the carbon is paired with a NiOOH electrode. This beneficial effect varies depending on the variety of carbon substrate to which it is applied. It has been conjectured that the sulfonic acid groups, which exist in a deprotonated state in aqueous KOH solutions, undergo reversible electro-chemical reactions that are responsible for the observed increases in energystorage capacities. The increases can be considerable: For example, in one case, nanofibers exhibited a specific capacitance of 34 Farads per gram before treatment and 172 Farads per gram (an increase of about 400 percent) after treatment. The most promising application of this development appears to lie in hybrid capacitors, which are devices designed primarily for storing energy. These devices are designed to be capable of (1) discharge at rates greater than those of batteries and (2) storing energy at densities approaching those of batteries. A hybrid capacitor includes one electrode like that of a battery and one electrode like that of an electrochemical capacitor. For example, a hybrid capacitor could contain a potassium hydroxide solution as the electrolyte

  9. Hydrogen storage in graphite nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Park, C.; Tan, C.D.; Hidalgo, R.; Baker, R.T.K.; Rodriguez, N.M. [Northeastern Univ., Boston, MA (United States). Chemistry Dept.

    1998-08-01

    Graphite nanofibers (GNF) are a type of material that is produced by the decomposition of carbon containing gases over metal catalyst particles at temperatures around 600 C. These molecularly engineered structures consist of graphene sheets perfectly arranged in a parallel, perpendicular or at angle orientation with respect to the fiber axis. The most important feature of the material is that only edges are exposed. Such an arrangement imparts the material with unique properties for gas adsorption because the evenly separated layers constitute the most ordered set of nanopores that can accommodate an adsorbate in the most efficient manner. In addition, the non-rigid pore walls can also expand so as to accommodate hydrogen in a multilayer conformation. Of the many varieties of structures that can be produced the authors have discovered that when gram quantities of a selected number of GNF are exposed to hydrogen at pressures of {approximately} 2,000 psi, they are capable of adsorbing and storing up to 40 wt% of hydrogen. It is believed that a strong interaction is established between hydrogen and the delocalized p-electrons present in the graphite layers and therefore a new type of chemistry is occurring within these confined structures.

  10. Preparation, characterization of electrospun meso-hydroxylapatite nanofibers and their sorptions on Co(II)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hualin, E-mail: hlwang@hfut.edu.cn [School of Chemical Technology, Hefei University of Technology, Hefei, Anhui 230009 (China); Zhang, Peng; Ma, Xingkong; Jiang, Suwei; Huang, Yan; Zhai, Linfeng [School of Chemical Technology, Hefei University of Technology, Hefei, Anhui 230009 (China); Jiang, Shaotong [School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui 230009 (China)

    2014-01-30

    Highlights: • PVA/HA nanofibers could change into meso-HA nanofibers by calcination process. • Sorption of Co(II) on meso-HA was strongly dependent on pH and ionic strength. • Sorption kinetic data were well fitted by the pseudo-second-order rate equation. • Sorption isotherms could be well described by the Langmuir model. • Sorption process of Co(II) on meso-HA nanofibers was spontaneous and endothermic. -- Abstract: In this work, mesoporous hydroxylapatite (meso-HA) nanofibers were prepared via calcination process with polyvinyl alcohol/HA (PVA/HA) hybrid nanofibers fabricated by electrospinning technique as precursors, and the removal efficiency of meso-HA nanofibers toward Co(II) was evaluated via sorption kinetics and sorption isotherms. Furthermore, the sorption behaviors of Co(II) on meso-HA nanofibers were explored as a function of pH, ionic strength, and thermodynamic parameters. There existed hydrogen bonds between HA and PVA matrix in precursor nanofibers which could change into meso-HA nanofibers with main pore diameter at 27 nm and specific surface area at 114.26 m{sup 2}/g by calcination process. The sorption of Co(II) on meso-HA was strongly dependent on pH and ionic strength. Outer-sphere surface complexation or ion exchange was the main mechanisms of Co(II) adsorption on meso-HA at low pH, whereas inner-sphere surface complexation was the main adsorption mechanism at high pH. The sorption kinetic data were well fitted by the pseudo-second-order rate equation. The sorption isotherms could be well described by the Langmuir model. The thermodynamic parameters (ΔH°, ΔS° and ΔG°) calculated from the temperature-dependent sorption isotherms suggested that the sorption process of Co(II) on meso-HA nanofibers was spontaneous and endothermic.

  11. Processing and Structure of Carbon Nanofiber Paper

    Directory of Open Access Journals (Sweden)

    Zhongfu Zhao

    2009-01-01

    Full Text Available A unique concept of making nanocomposites from carbon nanofiber paper was explored in this study. The essential element of this method was to design and manufacture carbon nanofiber paper with well-controlled and optimized network structure of carbon nanofibers. In this study, carbon nanofiber paper was prepared under various processing conditions, including different types of carbon nanofibers, solvents, dispersants, and acid treatment. The morphologies of carbon nanofibers within the nanofiber paper were characterized with scanning electron microscopy (SEM. In addition, the bulk densities of carbon nanofiber papers were measured. It was found that the densities and network structures of carbon nanofiber paper correlated to the dispersion quality of carbon nanofibers within the paper, which was significantly affected by papermaking process conditions.

  12. Gold nanorods contained polyvinyl alcohol/chitosan nanofiber matrix for cell imaging and drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Eryun, E-mail: yaney359@126.com [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Cao, Minglu [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006 (China); Wang, Yuwei; Hao, Xiaoyuan [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Pei, Shichun; Gao, Jianwei; Wang, Yan [College of Food and Biological Engineering, Qiqihar University, Qiqihar 161006 (China); Zhang, Zhuanfang [College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006 (China); Zhang, Deqing, E-mail: zhdqing@163.com [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China)

    2016-01-01

    Gold nanorods (AuNRs) that contained polyvinyl alcohol/chitosan (PVA/CS) hybrid nanofibers with dual functions are successfully fabricated by a simple electrospinning method. The results of transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) spectroscopy indicate that AuNRs are indeed encapsulated into the PVA/CS hybrid nanofibers. FTIR spectra results demonstrate that the chemical structures of PVA and CS are not affected when the AuNRs are introduced into the fibers. In vitro cytotoxicity test reveals that the hybrid fibers involving AuNRs are completely biocompatible. The as-prepared fibers can be used as a carrier for anticancer agent doxorubicin (DOX), and the drug is delivered into the cell nucleus. The AuNRs and DOX incorporated fibers are effective for inhibiting the growth and proliferation of ovary cancer cells and they can also be used as the cell imaging agent due to the unique optical properties of AuNRs. The nanofiber matrix combining two functions of cell imaging and drug delivery may be of great application potential in biomedical-related areas. - Highlights: • The AuNRs contained PVA/CS nanofibers are fabricated by electrospinning. • The hybrid fibers involving AuNRs are completely biocompatible. • The DOX loaded fibers are effective for inhibiting the proliferation of cancer cells. • The nanofibers combined two functions of cell imaging and drug delivery.

  13. Electrospun Metal Nanofiber Webs as High-Performance Transparent Electrode

    KAUST Repository

    Wu, Hui; Hu, Liangbing; Rowell, Michael W.; Kong, Desheng; Cha, Judy J.; McDonough, James R.; Zhu, Jia; Yang, Yuan; McGehee, Michael D.; Cui, Yi

    2010-01-01

    Transparent electrodes, indespensible in displays and solar cells, are currently dominated by indium tin oxide (ITO) films although the high price of indium, brittleness of films, and high vacuum deposition are limiting their applications. Recently, solution-processed networks of nanostructures such as carbon nanotubes (CNTs), graphene, and silver nanowires have attracted great attention as replacements. A low junction resistance between nanostructures is important for decreasing the sheet resistance. However, the junction resistances between CNTs and boundry resistances between graphene nanostructures are too high. The aspect ratios of silver nanowires are limited to ∼100, and silver is relatively expensive. Here, we show high-performance transparent electrodes with copper nanofiber networks by a low-cost and scalable electrospinning process. Copper nanofibers have ultrahigh aspect ratios of up to 100000 and fused crossing points with ultralow junction resistances, which result in high transmitance at low sheet resistance, e.g., 90% at 50 Ω/sq. The copper nanofiber networks also show great flexibility and stretchabilty. Organic solar cells using copper nanowire networks as transparent electrodes have a power efficiency of 3.0%, comparable to devices made with ITO electrodes. © 2010 American Chemical Society.

  14. Electrospun Metal Nanofiber Webs as High-Performance Transparent Electrode

    KAUST Repository

    Wu, Hui

    2010-10-13

    Transparent electrodes, indespensible in displays and solar cells, are currently dominated by indium tin oxide (ITO) films although the high price of indium, brittleness of films, and high vacuum deposition are limiting their applications. Recently, solution-processed networks of nanostructures such as carbon nanotubes (CNTs), graphene, and silver nanowires have attracted great attention as replacements. A low junction resistance between nanostructures is important for decreasing the sheet resistance. However, the junction resistances between CNTs and boundry resistances between graphene nanostructures are too high. The aspect ratios of silver nanowires are limited to ∼100, and silver is relatively expensive. Here, we show high-performance transparent electrodes with copper nanofiber networks by a low-cost and scalable electrospinning process. Copper nanofibers have ultrahigh aspect ratios of up to 100000 and fused crossing points with ultralow junction resistances, which result in high transmitance at low sheet resistance, e.g., 90% at 50 Ω/sq. The copper nanofiber networks also show great flexibility and stretchabilty. Organic solar cells using copper nanowire networks as transparent electrodes have a power efficiency of 3.0%, comparable to devices made with ITO electrodes. © 2010 American Chemical Society.

  15. Metal nanogrids, nanowires, and nanofibers for transparent electrodes

    KAUST Repository

    Hu, Liangbing; Wu, Hui; Cui, Yi

    2011-01-01

    Metals possess the highest conductivity among all room-temperature materials; however, ultrathin metal films demonstrate decent optical transparency but poor sheet conductance due to electron scattering from the surface and grain boundaries. This article discusses engineered metal nanostructures in the form of nanogrids, nanowires, or continuous nanofibers as efficient transparent and conductive electrodes. Metal nanogrids are discussed, as they represent an excellent platform for understanding the fundamental science. Progress toward low-cost, nano-ink-based printed silver nanowire electrodes, including silver nanowire synthesis, film fabrication, wire-wire junction resistance, optoelectronic properties, and stability, are also discussed. Another important factor for low-cost application is to use earth-abundant materials. Copper-based nanowires and nanofibers are discussed in this context. Examples of device integrations of these materials are also given. Such metal nanostructure-based transparent electrodes are particularly attractive for solar cell applications. © 2011 Materials Research Society.

  16. Metal nanogrids, nanowires, and nanofibers for transparent electrodes

    KAUST Repository

    Hu, Liangbing

    2011-10-01

    Metals possess the highest conductivity among all room-temperature materials; however, ultrathin metal films demonstrate decent optical transparency but poor sheet conductance due to electron scattering from the surface and grain boundaries. This article discusses engineered metal nanostructures in the form of nanogrids, nanowires, or continuous nanofibers as efficient transparent and conductive electrodes. Metal nanogrids are discussed, as they represent an excellent platform for understanding the fundamental science. Progress toward low-cost, nano-ink-based printed silver nanowire electrodes, including silver nanowire synthesis, film fabrication, wire-wire junction resistance, optoelectronic properties, and stability, are also discussed. Another important factor for low-cost application is to use earth-abundant materials. Copper-based nanowires and nanofibers are discussed in this context. Examples of device integrations of these materials are also given. Such metal nanostructure-based transparent electrodes are particularly attractive for solar cell applications. © 2011 Materials Research Society.

  17. Mechanism of nanofiber crimp

    Directory of Open Access Journals (Sweden)

    Chen Rou-Xi

    2013-01-01

    Full Text Available Fabrication of crimped fibers has been caught much attention recently due to remarkable improvement surface-to-volume ratio. The precise mechanism of the fiber crimp is, however, rare and preliminary. This paper finds that pulsation of fibers is the key factor for fiber crimp, and its configuration (wave formation corresponds to its nature frequency after solidification. Crimping performance can be improved by temperature control of the uncrimped fibers. In the paper, polylactide/ dimethylfomamide solution is fabricated into crimped nanofibers by the bubble electrospinning, an approximate period- amplitude relationship of the wave formation is obtained.

  18. Hydraulic Hybrid Vehicle Publications | Transportation Research | NREL

    Science.gov (United States)

    Hydraulic Hybrid Vehicle Publications Hydraulic Hybrid Vehicle Publications The following technical papers and fact sheets provide information about NREL's hydraulic hybrid fleet vehicle evaluations . Refuse Trucks Project Startup: Evaluating the Performance of Hydraulic Hybrid Refuse Vehicles. Bob

  19. Preparation of Biopolymeric Nanofiber Containing Silica and Antibiotic

    Directory of Open Access Journals (Sweden)

    A. Bagheri Pebdeni

    2016-01-01

    Full Text Available The biocompatible and biodegradable polymer nanofiber with high potential for anti-bacterial coating are used for: multi-functional membranes, tissue engineering, wound dressings, drug delivery, artificial organs, vascular grafts and etc. Electrospinning nanofiber made of scaffolding due to characteristics such as high surface to volume ratio, high porosity and very fine pores are used for a wide range of applications. In this study, polymer composite nanofiber Silica/chitosan/poly (ethylene oxide /cefepime antibiotic synthesis and antibacterial properties will be discussed. The optimum conditions for preparation of electrospun nanofiber were: voltage; 21 kV, feed rate; 0.5 mL/h, nozzle-collector distance; 10 cm, and chitosan/poly(ethylene oxide weight ratio 90:10 and the volume ratio of chitosan/silica is 70:30.  The antibacterial activity of composite scaffolds were tested by agar plate method by two type bacteria including Escherichia coli and Staphylococcus aureus. With the addition of the silica to chitosan, the hybrid was more biodegradable and improves the mechanical properties of biopolymer.

  20. Decontamination sheet

    International Nuclear Information System (INIS)

    Hirose, Emiko; Kanesaki, Ken.

    1995-01-01

    The decontamination sheet of the present invention is formed by applying an adhesive on one surface of a polymer sheet and releasably appending a plurality of curing sheets. In addition, perforated lines are formed on the sheet, and a decontaminating agent is incorporated in the adhesive. This can reduce the number of curing operation steps when a plurality steps of operations for radiation decontamination equipments are performed, and further, the amount of wastes of the cured sheets, and operator's exposure are reduced, as well as an efficiency of the curing operation can be improved, and propagation of contamination can be prevented. (T.M.)

  1. Templates for integrated nanofiber growth

    DEFF Research Database (Denmark)

    Oliveira Hansen, Roana Melina de

    the growth direction and the nanofiber length and position can be controlled by placement of nano-structured lines on the substrate. These lines can be used to guide the surface diffusion and thereby steer the self-assembly process of the organic molecules leading to morphologically well-defined molecular...... the morphology of the resulting structures leading to notably different electrical properties. The transistor design influences its electrical characteristics, and the top-gate configuration shows to have the stronger gate effect. In addition, platforms for light-emitting devices were fabricated......Para-hexaphenylene (p6P) molecules have the ability to self-assemble into organic nanofibers. These nanofibers hold unique optoelectronic properties, which make them interesting candidates as elements in electronic and optoelectronic devices. Typically these nanofibers are grown on specific single...

  2. Polyaniline-nylon-6 electrospun nanofibers for headspace adsorptive microextraction

    International Nuclear Information System (INIS)

    Bagheri, Habib; Aghakhani, Ali

    2012-01-01

    Highlights: ► Polyaniline–polyamide nanofiber mat was fabricated by electrospinning technology. ► Electrospun nanofiber was used for extraction of chlorobenzenes from aquatic media. ► A method based on headspace adsorptive microextraction and GC–MS was developed. - Abstract: A headspace adsorptive microextraction technique was developed using a novel polyaniline-nylon-6 (PANI-N6) nanofiber sheet, fabricated by electrospinning. The homogeneity and the porosity of the prepared PANI-N6 sheet were studied using the scanning electron microscopy (SEM) and nanofibers diameters were found to be around 200 nm. The novel nanofiber sheet was examined as an extracting medium to isolate some selected chlorobenzenes (CBs), as model compounds, from aquatic media. The extracted analytes were desorbed using μL-amounts of solvent and eventually an aliquot of extractant was injected into gas chromatography–mass spectrometry (GC–MS). Various parameters affecting the extraction and desorption processes were optimized. The developed method proved to be convenient and offers sufficient sensitivity and a good reproducibility. Limits of detection achieved for CBs with the developed analytical procedure ranged from 19 to 33 ng L −1 , while limits of quantification were from 50 to 60 ng L −1 . The relative standard deviations (RSD) at a concentration level of 0.1 ng mL −1 and 1 ng mL −1 were in the range of 8–14% and 5–11% (n = 3), respectively. The calibration curves of analytes were investigated in the range of 50–1000 ng L −1 and R 2 between 0.9739 and 0.9932 were obtained. The developed method was successfully applied to the extraction of selected CBs from tap and river water samples. The relative recovery (RR) percentage obtained for the spiked real water samples at 0.1 ng mL −1 and 1 ng mL −1 level were 93–103% and 95–104%, respectively. The whole procedure showed to be conveniently applicable and quite easy to handle.

  3. Polyaniline-nylon-6 electrospun nanofibers for headspace adsorptive microextraction

    Energy Technology Data Exchange (ETDEWEB)

    Bagheri, Habib, E-mail: bagheri@sharif.edu [Environmental and Bio-Analytical Laboratories, Department of Chemistry, Sharif University of Technology, P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of); Aghakhani, Ali [Environmental and Bio-Analytical Laboratories, Department of Chemistry, Sharif University of Technology, P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)

    2012-02-03

    Highlights: Black-Right-Pointing-Pointer Polyaniline-polyamide nanofiber mat was fabricated by electrospinning technology. Black-Right-Pointing-Pointer Electrospun nanofiber was used for extraction of chlorobenzenes from aquatic media. Black-Right-Pointing-Pointer A method based on headspace adsorptive microextraction and GC-MS was developed. - Abstract: A headspace adsorptive microextraction technique was developed using a novel polyaniline-nylon-6 (PANI-N6) nanofiber sheet, fabricated by electrospinning. The homogeneity and the porosity of the prepared PANI-N6 sheet were studied using the scanning electron microscopy (SEM) and nanofibers diameters were found to be around 200 nm. The novel nanofiber sheet was examined as an extracting medium to isolate some selected chlorobenzenes (CBs), as model compounds, from aquatic media. The extracted analytes were desorbed using {mu}L-amounts of solvent and eventually an aliquot of extractant was injected into gas chromatography-mass spectrometry (GC-MS). Various parameters affecting the extraction and desorption processes were optimized. The developed method proved to be convenient and offers sufficient sensitivity and a good reproducibility. Limits of detection achieved for CBs with the developed analytical procedure ranged from 19 to 33 ng L{sup -1}, while limits of quantification were from 50 to 60 ng L{sup -1}. The relative standard deviations (RSD) at a concentration level of 0.1 ng mL{sup -1} and 1 ng mL{sup -1} were in the range of 8-14% and 5-11% (n = 3), respectively. The calibration curves of analytes were investigated in the range of 50-1000 ng L{sup -1} and R{sup 2} between 0.9739 and 0.9932 were obtained. The developed method was successfully applied to the extraction of selected CBs from tap and river water samples. The relative recovery (RR) percentage obtained for the spiked real water samples at 0.1 ng mL{sup -1} and 1 ng mL{sup -1} level were 93-103% and 95-104%, respectively. The whole procedure showed

  4. General strategy for fabricating thoroughly mesoporous nanofibers

    KAUST Repository

    Hou, Huilin; Wang, Lin; Gao, Fengmei; Wei, Guodong; Tang, Bin; Yang, Weiyou; Wu, Tao

    2014-01-01

    mesoporous nanofibers with high purity and uniformity. Here, we report a general, simple and cost-effective strategy, namely, foaming-assisted electrospinning, for producing mesoporous nanofibers with high purity and enhanced specific surface areas. As a

  5. Properties of a New Nanofiber Restorative Composite.

    Science.gov (United States)

    Yancey, E M; Lien, W; Nuttall, C S; Brewster, J A; Roberts, H W; Vandewalle, K S

    2018-04-09

    A new nanofiber-reinforced hybrid composite (NovaPro Fill, Nanova) was recently introduced with reportedly improved mechanical properties. The purpose of this study was to compare the properties (flexural strength/modulus, degree of conversion [DC], depth of cure, and polymerization shrinkage) of the nanofiber composite to those of traditional hybrid composites (Filtek Z250, 3M ESPE; Esthet-X HD, Dentsply). To determine flexural strength and modulus, composite was placed in a rectangular mold, light-cured, stored for 24 hours, and then fractured in a universal testing machine. For degree of conversion, composite was placed in a cylindrical mold, light-cured, and stored for 24 hours. Measurements were made at the top and bottom surfaces using Fourier Transform Infrared Spectroscopy. To determine depth of cure, composite was placed in a cylindrical mold and light-cured. Uncured composite was scraped until polymerized resin was reached. Remaining composite was measured and divided by two. Polymerization shrinkage was determined by placing the composite material on a pedestal in a video-imaging device while light-curing. Shrinkage was determined after 10 minutes. Data were analyzed with one-way analysis of variance and Tukey post hoc test per property (α=0.05). Compared to Filtek Z250, NovaPro Fill had significantly lower flexural strength and modulus, greater volumetric shrinkage, and similar depth of cure, but greater top and bottom DC. Compared to Esthet-X HD, NovaPro Fill had similar flexural strength, shrinkage, and top and bottom DC, but significantly greater depth of cure and flexural modulus.

  6. Printed second harmonic active organic nanofiber arrays

    DEFF Research Database (Denmark)

    Balzer, Frank; Brewer, Jonathan R.; Kjelstrup-Hansen, Jakob

    2007-01-01

    Organic nanofibers from semiconducting conjugated molecules are well suited to meet refined demands for advanced applications in future optoelectronics and nanophotonics. In contrast to their inorganic counterparts, the properties of organic nanowires can be tailored at the molecular level...... investigated nanofibers as grown via organic epitaxy. In the present work we show how chemically changing the functionalizing end groups leads to a huge increase of second order susceptibility, making the nanofibers technologically very interesting as efficient frequency doublers. For that the nanofibers have...

  7. Double emulsion electrospun nanofibers as a growth factor delivery vehicle for salivary gland regeneration

    Science.gov (United States)

    Foraida, Zahraa I.; Sharikova, Anna; Peerzada, Lubna N.; Khmaladze, Alexander; Larsen, Melinda; Castracane, James

    2017-08-01

    Sustained delivery of growth factors, proteins, drugs and other biologically active molecules is necessary for tissue engineering applications. Electrospun fibers are attractive tissue engineering scaffolds as they partially mimic the topography of the extracellular matrix (ECM). However, they do not provide continuous nourishment to the tissue. In search of a biomimetic scaffold for salivary gland tissue regeneration, we previously developed a blend nanofiber scaffold composed of the protein elastin and the synthetic polymer polylactic-co-glycolic acid (PLGA). The nanofiber scaffold promoted in vivo-like salivary epithelial cell tissue organization and apicobasal polarization. However, in order to enhance the salivary cell proliferation and biomimetic character of the scaffold, sustained growth factor delivery is needed. The composite nanofiber scaffold was optimized to act as a growth factor delivery system using epidermal growth factor (EGF) as a model protein. The nanofiber/EGF hybrid nanofibers were synthesized by double emulsion electrospinning where EGF is emulsified within a water/oil/water (w/o/w) double emulsion system. Successful incorporation of EGF was confirmed using Raman spectroscopy. EGF release profile was characterized using enzyme-linked immunosorbent assay (ELIZA) of the EGF content. Double emulsion electrospinning resulted in slower release of EGF. We demonstrated the potential of the proposed double emulsion electrospun nanofiber scaffold for the delivery of growth factors and/or drugs for tissue engineering and pharmaceutical applications.

  8. Hybrid Filter Membrane

    Science.gov (United States)

    Laicer, Castro; Rasimick, Brian; Green, Zachary

    2012-01-01

    Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

  9. Electrospinning of Nanofibers for Energy Applications

    Science.gov (United States)

    Sun, Guiru; Sun, Liqun; Xie, Haiming; Liu, Jia

    2016-01-01

    With global concerns about the shortage of fossil fuels and environmental issues, the development of efficient and clean energy storage devices has been drastically accelerated. Nanofibers are used widely for energy storage devices due to their high surface areas and porosities. Electrospinning is a versatile and efficient fabrication method for nanofibers. In this review, we mainly focus on the application of electrospun nanofibers on energy storage, such as lithium batteries, fuel cells, dye-sensitized solar cells and supercapacitors. The structure and properties of nanofibers are also summarized systematically. The special morphology of nanofibers prepared by electrospinning is significant to the functional materials for energy storage. PMID:28335256

  10. Electrospinning of Nanofibers for Energy Applications

    Directory of Open Access Journals (Sweden)

    Guiru Sun

    2016-07-01

    Full Text Available With global concerns about the shortage of fossil fuels and environmental issues, the development of efficient and clean energy storage devices has been drastically accelerated. Nanofibers are used widely for energy storage devices due to their high surface areas and porosities. Electrospinning is a versatile and efficient fabrication method for nanofibers. In this review, we mainly focus on the application of electrospun nanofibers on energy storage, such as lithium batteries, fuel cells, dye-sensitized solar cells and supercapacitors. The structure and properties of nanofibers are also summarized systematically. The special morphology of nanofibers prepared by electrospinning is significant to the functional materials for energy storage.

  11. Aligned Layers of Silver Nano-Fibers

    Directory of Open Access Journals (Sweden)

    Andrii B. Golovin

    2012-02-01

    Full Text Available We describe a new dichroic polarizers made by ordering silver nano-fibers to aligned layers. The aligned layers consist of nano-fibers and self-assembled molecular aggregates of lyotropic liquid crystals. Unidirectional alignment of the layers is achieved by means of mechanical shearing. Aligned layers of silver nano-fibers are partially transparent to a linearly polarized electromagnetic radiation. The unidirectional alignment and density of the silver nano-fibers determine degree of polarization of transmitted light. The aligned layers of silver nano-fibers might be used in optics, microwave applications, and organic electronics.

  12. Oriented nanofibers embedded in a polymer matrix

    Science.gov (United States)

    Barrera, Enrique V. (Inventor); Lozano, Karen (Inventor); Rodriguez-Macias, Fernando J. (Inventor); Chibante, Luis Paulo Felipe (Inventor); Stewart, David Harris (Inventor)

    2011-01-01

    A method of forming a composite of embedded nanofibers in a polymer matrix is disclosed. The method includes incorporating nanofibers in a plastic matrix forming agglomerates, and uniformly distributing the nanofibers by exposing the agglomerates to hydrodynamic stresses. The hydrodynamic said stresses force the agglomerates to break apart. In combination or additionally elongational flow is used to achieve small diameters and alignment. A nanofiber reinforced polymer composite system is disclosed. The system includes a plurality of nanofibers that are embedded in polymer matrices in micron size fibers. A method for producing nanotube continuous fibers is disclosed. Nanofibers are fibrils with diameters of 100 nm, multiwall nanotubes, single wall nanotubes and their various functionalized and derivatized forms. The method includes mixing a nanofiber in a polymer; and inducing an orientation of the nanofibers that enables the nanofibers to be used to enhance mechanical, thermal and electrical properties. Orientation is induced by high shear mixing and elongational flow, singly or in combination. The polymer may be removed from said nanofibers, leaving micron size fibers of aligned nanofibers.

  13. Nanofibers made of globular proteins.

    Science.gov (United States)

    Dror, Yael; Ziv, Tamar; Makarov, Vadim; Wolf, Hila; Admon, Arie; Zussman, Eyal

    2008-10-01

    Strong nanofibers composed entirely of a model globular protein, namely, bovine serum albumin (BSA), were produced by electrospinning directly from a BSA solution without the use of chemical cross-linkers. Control of the spinnability and the mechanical properties of the produced nanofibers was achieved by manipulating the protein conformation, protein aggregation, and intra/intermolecular disulfide bonds exchange. In this manner, a low-viscosity globular protein solution could be modified into a polymer-like spinnable solution and easily spun into fibers whose mechanical properties were as good as those of natural fibers made of fibrous protein. We demonstrate here that newly formed disulfide bonds (intra/intermolecular) have a dominant role in both the formation of the nanofibers and in providing them with superior mechanical properties. Our approach to engineer proteins into biocompatible fibrous structures may be used in a wide range of biomedical applications such as suturing, wound dressing, and wound closure.

  14. Oilseed rape grain yield productivity increases with hybrid varietal types: a first balance sheet with post registration tests in France and in Europe

    Directory of Open Access Journals (Sweden)

    Pinochet Xavier

    2000-01-01

    Full Text Available Since 1994 several oilseed rape hybrid types were proposed to farmers. Following registration experiments, Cetiom and different equivalent institutions in European Union have tested them in different post registration national networks. Grain yield productivity increases were demonstrated and a first synthesis could be done to check avantages and difficulties which had occurred. For winter types, Hybrid Composits were widely used, mainly in France and in the United Kingdom. Grain yield increases were important in the South and West part of France where their market shares increased up to 50-80%. Nevertheless, many fecondation problems occurred in several places all over Europe. Reasons of such problems were difficult to identify. Several factors, as cold temperatures, nutritionnal competitions, pollen avaibility may be involved to explain low seed sets. Restored Hybrids made with the NPZ hybridation system were successfully tested widely, and has reached significative market shares during 1999-2000 season. Less experiments were carried out with others hybrid types (Ogu-INRA Restored Hybrids, Mixed Hybrids. Ogu-INRA Restored Hybrids reached the highest grain yield levels but users are waiting for lower glucosinolates seed content hybrids which would come in the next future. Performances comparisons among countries have to be done carefully. Productivity increases with hybrid types could have been over estimated depending of pollinic environments or plot size and possible neighbouring effects. For France, results from field trials networks are coherent with results coming from postal surveys. For spring varieties, Polima restored hybrids and varietal associations have demonstrated a significative advantage compared to classical lines.

  15. Electrospun Polymer Nanofibers Decorated with Noble Metal Nanoparticles for Chemical Sensing.

    Science.gov (United States)

    Chen, Chen; Tang, Yongan; Vlahovic, Branislav; Yan, Fei

    2017-12-01

    The integration of different noble metal nanostructures, which exhibit desirable plasmonic and/or electrocatalytic properties, with electrospun polymer nanofibers, which display unique mechanical and thermodynamic properties, yields novel hybrid nanoscale systems of synergistic properties and functions. This review summarizes recent advances on how to incorporate noble metal nanoparticles into electrospun polymer nanofibers and illustrates how such integration paves the way towards chemical sensing applications with improved sensitivity, stability, flexibility, compatibility, and selectivity. It is expected that further development of this field will eventually make a wide impact on many areas of research.

  16. Nanocontainers in and onto Nanofibers.

    Science.gov (United States)

    Jiang, Shuai; Lv, Li-Ping; Landfester, Katharina; Crespy, Daniel

    2016-05-17

    Hierarchical structure is a key feature explaining the superior properties of many materials in nature. Fibers usually serve in textiles, for structural reinforcement, or as support for other materials, whereas spherical micro- and nanoobjects can be either highly functional or also used as fillers to reinforce structure materials. Combining nanocontainers with fibers in one single object has been used to increase the functionality of fibers, for example, antibacterial and thermoregulation, when the advantageous properties given by the encapsulated materials inside the containers are transferred to the fibers. Herein we focus our discussion on how the hierarchical structure composed of nanocontainers in nanofibers yields materials displaying advantages of both types of materials and sometimes synergetical effects. Such materials can be produced by first carefully designing nanocontainers with defined morphology and chemistry and subsequently electrospinning them to fabricate nanofibers. This method, called colloid-electrospinning, allows for marrying the properties of nanocontainers and nanofibers. The obtained fibers could be successfully applied in different fields such as catalysis, optics, energy conversion and production, and biomedicine. The miniemulsion process is a convenient approach for the encapsulation of hydrophobic or hydrophilic payloads in nanocontainers. These nanocontainers can be embedded in fibers by the colloid-electrospinning technique. The combination of nanocontainers with nanofibers by colloid-electrospinning has several advantages. (1) The fiber matrix serves as support for the embedded nanocontainers. For example, through combining catalysts nanoparticles with fiber networks, the catalysts can be easily separated from the reaction media and handled visually. This combination is beneficial for the reuse of the catalyst and the purification of products. (2) Electrospun nanofibers containing nanocontainers offer the active agents inside the

  17. Immobilization of CoCl2 (cobalt chloride) on PAN (polyacrylonitrile) composite nanofiber mesh filled with carbon nanotubes for hydrogen production from hydrolysis of NaBH4 (sodium borohydride)

    International Nuclear Information System (INIS)

    Li, Fang; Arthur, Ernest Evans; La, Dahye; Li, Qiming; Kim, Hern

    2014-01-01

    Composite nanofiber sheets containing multiwalled carbon nanotubes and cobalt chloride dispersed in PAN (polyacrylonitrile) were produced by an electrospinning technique. The synthesized PAN/CoCl 2 /CNTs composite nanofiber was used as the catalyst for hydrogen production from the hydrolysis of sodium borohydride. FT-IR characterization showed that the pretreated CNTs possess different organic functional groups which help improve the compatibility between CNTs and PAN organic polymer. SEM (scanning electron microscopy), TEM (transmission electron microscopy) and EDX (energy-dispersive X-ray technique) were used to characterize the composite nanofiber and it was found that CNTs can be coaxially dispersed into the PAN nanofiber. During the hydrolysis of NaBH 4 , this PAN/CoCl 2 /CNTs composite nanofiber exhibited higher catalytic activity compared to the composite without CNTs doping. Kinetic analysis of NaBH 4 hydrolysis shows that the reaction of NaBH 4 hydrolysis based on this catalyst can be ascribed to the first-order reaction and the activation energy of the catalyst was approximately 52.857 kJ/mol. Meanwhile, the composite nanofiber catalyst shows excellent stability and reusability in the recycling experiment. - Highlights: • Composite nanofiber sheets were prepared via electrospinning. • PAN (polyacrylonitrile)/CoCl 2 (cobalt chloride)/CNTs (carbon nanotubes) nanofiber was used as the catalyst for hydrogen production. • CNTs can be coaxially dispersed into the PAN nanofiber. • PAN/CoCl 2 /CNTs composite nanofiber exhibited higher catalytic activity. • The composite nanofiber catalyst shows excellent stability and reusability

  18. Polyaniline nanofiber/large mesoporous carbon composites as electrode materials for supercapacitors

    Science.gov (United States)

    Liu, Huan; Xu, Bin; Jia, Mengqiu; Zhang, Mei; Cao, Bin; Zhao, Xiaonan; Wang, Yu

    2015-03-01

    A composite of polyaniline nanofiber/large mesoporous carbon (PANI-F/LMC) hybrid was prepared by an in situ chemical oxidative polymerization of aniline monomer with nano-CaCO3 templated LMC as host matrix for supercapacitors. The morphology, composition and electronic structure of the composites (PANI-F/LMC) together with pure PANI nanofibers and the LMC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found that the PANI nanofibers were incorporated into the large mesochannels of LMC with interpenetrating framework formed. Such unique structure endows the PANI-F/LMC composite with a high capacitance of 473 F g-1 at a current load of 0.1 A g-1 with good rate performance and cycling stability, suggesting its potential application in the electrode material for supercapacitors.

  19. Electrospinning of polymeric nanofibers for drug delivery applications.

    Science.gov (United States)

    Hu, Xiuli; Liu, Shi; Zhou, Guangyuan; Huang, Yubin; Xie, Zhigang; Jing, Xiabin

    2014-07-10

    Electrospinning has been recognized as a simple and versatile method for fabrication of polymer nanofibers. Various polymers that include synthetic, natural, and hybrid materials have been successfully electrospun into ultrafine fibers. The inherently high surface to volume ratio of electrospun fibers can enhance cell attachment, drug loading, and mass transfer properties. Drugs ranging from antibiotics and anticancer agents to proteins, DNA, RNA, living cells, and various growth factors have been incorporated into electrospun fibers. This article presents an overview of electrospinning techniques and their application in drug delivery. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Mechanical properties of organic nanofibers

    DEFF Research Database (Denmark)

    Kjelstrup-Hansen, Jakob; Hansen, Ole; Rubahn, H.R.

    2006-01-01

    Intrinsic elastic and inelastic mechanical Properties of individual, self-assembled, quasi-single-crystalline para-hexaphenylene nanofibers supported on substrates with different hydrophobicities are investigated as well as the interplay between the fibers and the underlying substrates. We find...

  1. The Electrospun Ceramic Hollow Nanofibers

    Directory of Open Access Journals (Sweden)

    Shahin Homaeigohar

    2017-11-01

    Full Text Available Hollow nanofibers are largely gaining interest from the scientific community for diverse applications in the fields of sensing, energy, health, and environment. The main reasons are: their extensive surface area that increases the possibilities of engineering, their larger accessible active area, their porosity, and their sensitivity. In particular, semiconductor ceramic hollow nanofibers show greater space charge modulation depth, higher electronic transport properties, and shorter ion or electron diffusion length (e.g., for an enhanced charging–discharging rate. In this review, we discuss and introduce the latest developments of ceramic hollow nanofiber materials in terms of synthesis approaches. Particularly, electrospinning derivatives will be highlighted. The electrospun ceramic hollow nanofibers will be reviewed with respect to their most widely studied components, i.e., metal oxides. These nanostructures have been mainly suggested for energy and environmental remediation. Despite the various advantages of such one dimensional (1D nanostructures, their fabrication strategies need to be improved to increase their practical use. The domain of nanofabrication is still advancing, and its predictable shortcomings and bottlenecks must be identified and addressed. Inconsistency of the hollow nanostructure with regard to their composition and dimensions could be one of such challenges. Moreover, their poor scalability hinders their wide applicability for commercialization and industrial use.

  2. RGO/InVO4 hollowed-out nanofibers: Electrospinning synthesis and its application in photocatalysis

    International Nuclear Information System (INIS)

    Ma, Dong; Zhang, Yanxiang; Gao, Mengchun; Xin, Yanjun; Wu, Juan; Bao, Nan

    2015-01-01

    Graphical abstract: - Highlights: • RGO/InVO 4 hollow-out nanofibers were obtained by electrospinning method. • The properties of InVO 4 hollow-out nanofibers were deeply influenced by RGO. • RGO could reduce recombination of e − –h + pairs to improve photocatalytic activity. • Photo-induced h + and e − are the two main reactive species for RhB degradation. - Abstract: A composite of reduced graphene oxide (RGO) and InVO 4 nanofiber was successfully synthesized by an electrospinning technique. The as-collected fibers were calcined at 420 °C in air and then calcined at 550 °C in nitrogen gas to remove polyvinyl pyrrolidone (PVP), which could enable InVO 4 to crystallize and protect the RGO from oxidation. The InVO 4 in the composite illustrated a hollowed-out fibrous morphology and orthorhombic phase, and RGO nanosheets were nested in the InVO 4 nanofibers. The hybrid RGO could produce more hydroxyl groups and a higher oxygen vacancy density on the surface of RGO/InVO 4 composite. Compared with pure InVO 4 , the light absorption range of the as-prepared RGO/InVO 4 composite was expanded. In Rh B degradation, the RGO/InVO 4 hybrid nanofibers displayed a higher photocatalytic activity than pure InVO 4 nanofibers. The enhanced photocatalytic activity might be ascribed to the role of RGO as an electron transporter and acceptor in the composite, which could effectively inhibit the charge recombination and facilitate the charge transfer. The exported electron could attack an O 2 molecule to facilitate the generation of • O 2 − and • OH for the photodegradation process of Rh B.

  3. Biomimetic electrospun nanofibers for tissue regeneration

    International Nuclear Information System (INIS)

    Liao, Susan; Li Bojun; Ma Zuwei; Wei He; Chan Casey; Ramakrishna, Seeram

    2006-01-01

    Nanofibers exist widely in human tissue with different patterns. Electrospinning nanotechnology has recently gained a new impetus due to the introduction of the concept of biomimetic nanofibers for tissue regeneration. The advanced electrospinning technique is a promising method to fabricate a controllable continuous nanofiber scaffold similar to the natural extracellular matrix. Thus, the biomedical field has become a significant possible application field of electrospun fibers. Although electrospinning has developed rapidly over the past few years, electrospun nanofibers are still at a premature research stage. Further comprehensive and deep studies on electrospun nanofibers are essential for promoting their biomedical applications. Current electrospun fiber materials include natural polymers, synthetic polymers and inorganic substances. This review briefly describes several typically electrospun nanofiber materials or composites that have great potential for tissue regeneration, and describes their fabrication, advantages, drawbacks and future prospects. (topical review)

  4. Effects of Sn doping on the morphology, structure, and electrical property of In{sub 2}O{sub 3} nanofiber networks

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xu; Wang, Yihua [Zhejiang Sci-Tech University, College of Materials and Textiles, Hangzhou (China); Yang, Bin [Zhejiang Sci-Tech University, Ministry of Education, Key Laboratory of Advanced Textile Materials and Manufacturing Technology, College of Materials and Textiles, Hangzhou (China); Zhejiang Sci-Tech University, College of Materials and Textiles, Hangzhou (China)

    2014-11-15

    This paper studies the effect of Sn doping on the morphological, structural, and electrical properties of the Sn-doping In{sub 2}O{sub 3} nanofiber networks. In{sub 2}O{sub 3}-based nanofibers with various relative concentration of Sn precursor (0-20 mol%) were fabricated through the electrospinning method. Scanning electron microscopy observations show that, depending on the relative concentration of SnCl{sub 4} in the starting materials, the doped nanofibers with different morphologies, from smooth to corn-like and then to accidented, are fabricated. Transmission electron microscopy and X-ray diffraction analyses reveal that the Sn dopants influence the growth direction of seeds, resulting in doped nanoparticles having diverse shapes and sizes, which are critical for the formation of doped nanofiber with different morphology. From these nanofiber networks, we fabricated several thin sheets to characterize the effect of Sn concentration on the electrical resistivity. The resistivity of thin sheets decreased significantly before the doping concentration up to 12.5 mol%, and then increased slightly at a larger addition. This work will assist further understanding the formation of Sn-doped In{sub 2}O{sub 3} nanofibers and is expected to be extended to other transparent conductive oxides. (orig.)

  5. Atmospheric Pressure Plasma-Electrospin Hybrid Process for Protective Applications

    Science.gov (United States)

    Vitchuli Gangadharan, Narendiran

    2011-12-01

    Chemical and biological (C-B) warfare agents like sarin, sulfur mustard, anthrax are usually dispersed into atmosphere in the form of micro aerosols. They are considered to be dangerous weapon of mass destruction next to nuclear weapons. The airtight protective clothing materials currently available are able to stop the diffusion of threat agents but not good enough to detoxify them, which endangers the wearers. Extensive research efforts are being made to prepare advanced protective clothing materials that not only prevent the diffusion of C-B agents, but also detoxify them into harmless products thus ensuring the safety and comfort of the wearer. Electrospun nanofiber mats are considered to have effective filtration characteristics to stop the diffusion of submicron level particulates without sacrificing air permeability characteristics and could be used in protective application as barrier material. In addition, functional nanofibers could be potentially developed to detoxify the C-B warfare threats into harmless products. In this research, electrospun nanofibers were deposited on fabric surface to improve barrier efficiency without sacrificing comfort-related properties of the fabrics. Multi-functional nanofibers were fabricated through an electrospinning-electrospraying hybrid process and their ability to detoxify simulants of C-B agents was evaluated. Nanofibers were also deposited onto plasma-pretreated woven fabric substrate through a newly developed plasma-electrospinning hybrid process, to improve the adhesive properties of nanofibers on the fabric surface. The nanofiber adhesion and durability properties were evaluated by peel test, flex and abrasion resistance tests. In this research work, following tasks have been carried out: i) Controlled deposition of nanofiber mat onto woven fabric substrate Electrospun Nylon 6 fiber mats were deposited onto woven 50/50 Nylon/Cotton fabric with the motive of making them into protective material against submicron

  6. Electrospun nanofiber scaffolds: engineering soft tissues

    International Nuclear Information System (INIS)

    Kumbar, S G; Nukavarapu, S P; Laurencin, C T; James, R

    2008-01-01

    Electrospinning has emerged to be a simple, elegant and scalable technique to fabricate polymeric nanofibers. Pure polymers as well as blends and composites of both natural and synthetics have been successfully electrospun into nanofiber matrices. Physiochemical properties of nanofiber matrices can be controlled by manipulating electrospinning parameters to meet the requirements of a specific application. Such efforts include the fabrication of fiber matrices containing nanofibers, microfibers, combination of nano-microfibers and also different fiber orientation/alignments. Polymeric nanofiber matrices have been extensively investigated for diversified uses such as filtration, barrier fabrics, wipes, personal care, biomedical and pharmaceutical applications. Recently electrospun nanofiber matrices have gained a lot of attention, and are being explored as scaffolds in tissue engineering due to their properties that can modulate cellular behavior. Electrospun nanofiber matrices show morphological similarities to the natural extra-cellular matrix (ECM), characterized by ultrafine continuous fibers, high surface-to-volume ratio, high porosity and variable pore-size distribution. Efforts have been made to modify nanofiber surfaces with several bioactive molecules to provide cells with the necessary chemical cues and a more in vivo like environment. The current paper provides an overlook on such efforts in designing nanofiber matrices as scaffolds in the regeneration of various soft tissues including skin, blood vessel, tendon/ligament, cardiac patch, nerve and skeletal muscle

  7. Electrospun nanofiber scaffolds: engineering soft tissues

    Energy Technology Data Exchange (ETDEWEB)

    Kumbar, S G; Nukavarapu, S P; Laurencin, C T [Department of Orthopaedic Surgery, University of Virginia, VA 22908 (United States); James, R [Department of Biomedical Engineering, University of Virginia, VA 22908 (United States)], E-mail: laurencin@virginia.edu

    2008-09-01

    Electrospinning has emerged to be a simple, elegant and scalable technique to fabricate polymeric nanofibers. Pure polymers as well as blends and composites of both natural and synthetics have been successfully electrospun into nanofiber matrices. Physiochemical properties of nanofiber matrices can be controlled by manipulating electrospinning parameters to meet the requirements of a specific application. Such efforts include the fabrication of fiber matrices containing nanofibers, microfibers, combination of nano-microfibers and also different fiber orientation/alignments. Polymeric nanofiber matrices have been extensively investigated for diversified uses such as filtration, barrier fabrics, wipes, personal care, biomedical and pharmaceutical applications. Recently electrospun nanofiber matrices have gained a lot of attention, and are being explored as scaffolds in tissue engineering due to their properties that can modulate cellular behavior. Electrospun nanofiber matrices show morphological similarities to the natural extra-cellular matrix (ECM), characterized by ultrafine continuous fibers, high surface-to-volume ratio, high porosity and variable pore-size distribution. Efforts have been made to modify nanofiber surfaces with several bioactive molecules to provide cells with the necessary chemical cues and a more in vivo like environment. The current paper provides an overlook on such efforts in designing nanofiber matrices as scaffolds in the regeneration of various soft tissues including skin, blood vessel, tendon/ligament, cardiac patch, nerve and skeletal muscle.

  8. Investigation of needleless electrospun PAN nanofiber mats

    Science.gov (United States)

    Sabantina, Lilia; Mirasol, José Rodríguez; Cordero, Tomás; Finsterbusch, Karin; Ehrmann, Andrea

    2018-04-01

    Polyacrylonitrile (PAN) can be spun from a nontoxic solvent (DMSO, dimethyl sulfoxide) and is nevertheless waterproof, opposite to the biopolymers which are spinnable from aqueous solutions. This makes PAN an interesting material for electrospinning nanofiber mats which can be used for diverse biotechnological or medical applications, such as filters, cell growth, wound healing or tissue engineering. On the other hand, PAN is a typical base material for producing carbon nanofibers. Nevertheless, electrospinning PAN necessitates convenient spinning parameters to create nanofibers without too many membranes or agglomerations. Thus we have studied the influence of spinning parameters on the needleless electrospinning process of PAN dissolved in DMSO and the resulting nanofiber mats.

  9. Biscrolling nanotube sheets and functional guests into yarns.

    Science.gov (United States)

    Lima, Márcio D; Fang, Shaoli; Lepró, Xavier; Lewis, Chihye; Ovalle-Robles, Raquel; Carretero-González, Javier; Castillo-Martínez, Elizabeth; Kozlov, Mikhail E; Oh, Jiyoung; Rawat, Neema; Haines, Carter S; Haque, Mohammad H; Aare, Vaishnavi; Stoughton, Stephanie; Zakhidov, Anvar A; Baughman, Ray H

    2011-01-07

    Multifunctional applications of textiles have been limited by the inability to spin important materials into yarns. Generically applicable methods are demonstrated for producing weavable yarns comprising up to 95 weight percent of otherwise unspinnable particulate or nanofiber powders that remain highly functional. Scrolled 50-nanometer-thick carbon nanotube sheets confine these powders in the galleries of irregular scroll sacks whose observed complex structures are related to twist-dependent extension of Archimedean spirals, Fermat spirals, or spiral pairs into scrolls. The strength and electronic connectivity of a small weight fraction of scrolled carbon nanotube sheet enables yarn weaving, sewing, knotting, braiding, and charge collection. This technology is used to make yarns of superconductors, lithium-ion battery materials, graphene ribbons, catalytic nanofibers for fuel cells, and titanium dioxide for photocatalysis.

  10. Functionalized graphene oxide-reinforced electrospun carbon nanofibers as ultrathin supercapacitor electrode

    Institute of Scientific and Technical Information of China (English)

    W.K.Chee; H.N.Lim; Y.Andou; Z.Zainal; A.A.B.Hamra; I.Harrison; M.Altarawneh; Z.T.Jiang; N.M.Huang

    2017-01-01

    Graphene oxide has been used widely as a starting precursor for applications that cater to the needs of tunable graphene. However, the hydrophilic characteristic limits their application, especially in a hydrophobic condition. Herein, a novel non-covalent surface modification approach towards graphene oxide was conducted via a UV-induced photo-polymerization technique that involves two major routes; a UV-sensitive initiator embedded via pi-pi interactions on the graphene planar rings, and the polymerization of hydrophobic polymeric chains along the surface. The functionalized graphene oxide successfully achieved the desired hydrophobicity as it displayed the characteristic of being readily dissolved in organic solvent. Upon its addition into a polymeric solution and subjected to an electrospinning process,non-woven random nanofibers embedded with graphene oxide sheets were obtained. The prepared polymeric nanofibers were subjected to two-step thermal treatments that eventually converted the polymeric chains into a carbon-rich conductive structure. A unique morphology was observed upon the addition of the functionalized graphene oxide, whereby the sheets were embedded and intercalated within the carbon nanofibers and formed a continuous structure. This reinforcement effectively enhanced the electrochemical performance of the carbon nanofibers by recording a specific capacitance of up to 140.10 F/g at the current density of 1 A/g, which was approximately three folds more than that of pristine nanofibers.It also retained the capacitance up to 96.2% after 1000 vigorous charge/discharge cycles. This functionalization technique opens up a new pathway in tuning the solubility nature of graphene oxide towards the synthesis of a graphene oxide-reinforced polymeric structure.

  11. Evaluation of the genotoxicity of cellulose nanofibers.

    Science.gov (United States)

    de Lima, Renata; Oliveira Feitosa, Leandro; Rodrigues Maruyama, Cintia; Abreu Barga, Mariana; Yamawaki, Patrícia Cristina; Vieira, Isolda Jesus; Teixeira, Eliangela M; Corrêa, Ana Carolina; Caparelli Mattoso, Luiz Henrique; Fernandes Fraceto, Leonardo

    2012-01-01

    Agricultural products and by products provide the primary materials for a variety of technological applications in diverse industrial sectors. Agro-industrial wastes, such as cotton and curaua fibers, are used to prepare nanofibers for use in thermoplastic films, where they are combined with polymeric matrices, and in biomedical applications such as tissue engineering, amongst other applications. The development of products containing nanofibers offers a promising alternative for the use of agricultural products, adding value to the chains of production. However, the emergence of new nanotechnological products demands that their risks to human health and the environment be evaluated. This has resulted in the creation of the new area of nanotoxicology, which addresses the toxicological aspects of these materials. Contributing to these developments, the present work involved a genotoxicological study of different nanofibers, employing chromosomal aberration and comet assays, as well as cytogenetic and molecular analyses, to obtain preliminary information concerning nanofiber safety. The methodology consisted of exposure of Allium cepa roots, and animal cell cultures (lymphocytes and fibroblasts), to different types of nanofibers. Negative controls, without nanofibers present in the medium, were used for comparison. The nanofibers induced different responses according to the cell type used. In plant cells, the most genotoxic nanofibers were those derived from green, white, and brown cotton, and curaua, while genotoxicity in animal cells was observed using nanofibers from brown cotton and curaua. An important finding was that ruby cotton nanofibers did not cause any significant DNA breaks in the cell types employed. This work demonstrates the feasibility of determining the genotoxic potential of nanofibers derived from plant cellulose to obtain information vital both for the future usage of these materials in agribusiness and for an understanding of their environmental

  12. Electrospun MOF nanofibers as hydrogen storage media

    CSIR Research Space (South Africa)

    Ren, Jianwei

    2015-06-01

    Full Text Available showed that the incorporation of vacuum degassing was able to create visible porosity in and/or on the PAN nanofibers and the MOF nanocrystals inside the polymeric nanofibers were fully accessible by N2 and H2 gases. With 20 wt.% loading of MOF...

  13. Antibacterial properties of laser spinning glass nanofibers.

    Science.gov (United States)

    Echezarreta-López, M M; De Miguel, T; Quintero, F; Pou, J; Landin, M

    2014-12-30

    A laser-spinning technique has been used to produce amorphous, dense and flexible glass nanofibers of two different compositions with potential utility as reinforcement materials in composites, fillers in bone defects or scaffolds (3D structures) for tissue engineering. Morphological and microstructural analyses have been carried out using SEM-EDX, ATR-FTIR and TEM. Bioactivity studies allow the nanofibers with high proportion in SiO2 (S18/12) to be classified as a bioinert glass and the nanofibers with high proportion of calcium (ICIE16) as a bioactive glass. The cell viability tests (MTT) show high biocompatibility of the laser spinning glass nanofibers. Results from the antibacterial activity study carried out using dynamic conditions revealed that the bioactive glass nanofibers show a dose-dependent bactericidal effect on Sthaphylococcus aureus (S. aureus) while the bioinert glass nanofibers show a bacteriostatic effect also dose-dependent. The antibacterial activity has been related to the release of alkaline ions, the increase of pH of the medium and also the formation of needle-like aggregates of calcium phosphate at the surface of the bioactive glass nanofibers which act as a physical mechanism against bacteria. The antibacterial properties give an additional value to the laser-spinning glass nanofibers for different biomedical applications, such as treating or preventing surgery-associated infections. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Electrospun polymeric nanofibers for transdermal drug delivery

    Directory of Open Access Journals (Sweden)

    Mahya Rahmani

    2017-04-01

    Full Text Available Conventional transdermal drug delivery systems (TDDS have been designed for drug delivery through the skin. These systems use the permeability property of stratum corneum, the outermost surface layer of the skin. Applying polymeric micro and nanofibers in drug delivery has recently attracted great attention and the electrospinning technique is the preferred method for polymeric micro-nanofibers fabrication with a great potential for drug delivery. More studies in the field of nanofibers containing drug are divided two categories: first, preparation and characterization of nanofibers containing drug and second, investigation of their therapeutic applications. Drugs used in electrospun nanofibers can be categorized into three main groups, including antibiotics and antimicrobial agents, anti-inflammatory agents and vitamins with therapeutic applications. In this paper, we review the application of electrospun polymeric scaffolds in TDDS and also introduce several pharmaceutical and therapeutic agents which have been used in polymer nanofibrous patches.

  15. Thermal conductivity model for nanofiber networks

    Science.gov (United States)

    Zhao, Xinpeng; Huang, Congliang; Liu, Qingkun; Smalyukh, Ivan I.; Yang, Ronggui

    2018-02-01

    Understanding thermal transport in nanofiber networks is essential for their applications in thermal management, which are used extensively as mechanically sturdy thermal insulation or high thermal conductivity materials. In this study, using the statistical theory and Fourier's law of heat conduction while accounting for both the inter-fiber contact thermal resistance and the intrinsic thermal resistance of nanofibers, an analytical model is developed to predict the thermal conductivity of nanofiber networks as a function of their geometric and thermal properties. A scaling relation between the thermal conductivity and the geometric properties including volume fraction and nanofiber length of the network is revealed. This model agrees well with both numerical simulations and experimental measurements found in the literature. This model may prove useful in analyzing the experimental results and designing nanofiber networks for both high and low thermal conductivity applications.

  16. Thermal conductivity model for nanofiber networks

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xinpeng [Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA; Huang, Congliang [Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA; School of Electrical and Power Engineering, China University of Mining and Technology, Xuzhou 221116, China; Liu, Qingkun [Department of Physics, University of Colorado, Boulder, Colorado 80309, USA; Smalyukh, Ivan I. [Department of Physics, University of Colorado, Boulder, Colorado 80309, USA; Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80309, USA; Yang, Ronggui [Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA; Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80309, USA; Buildings and Thermal Systems Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA

    2018-02-28

    Understanding thermal transport in nanofiber networks is essential for their applications in thermal management, which are used extensively as mechanically sturdy thermal insulation or high thermal conductivity materials. In this study, using the statistical theory and Fourier's law of heat conduction while accounting for both the inter-fiber contact thermal resistance and the intrinsic thermal resistance of nanofibers, an analytical model is developed to predict the thermal conductivity of nanofiber networks as a function of their geometric and thermal properties. A scaling relation between the thermal conductivity and the geometric properties including volume fraction and nanofiber length of the network is revealed. This model agrees well with both numerical simulations and experimental measurements found in the literature. This model may prove useful in analyzing the experimental results and designing nanofiber networks for both high and low thermal conductivity applications.

  17. Growth of Y-shaped Carbon Nanofibers from Ethanol Flames

    Directory of Open Access Journals (Sweden)

    Cheng Jin

    2008-01-01

    Full Text Available Abstract Y-shaped carbon nanofibers as a multi-branched carbon nanostructure have potential applications in electronic devices. In this article, we report that several types of Y-shaped carbon nanofibers are obtained from ethanol flames. These Y-shaped carbon nanofibers have different morphologies. According to our experimental results, the growth mechanism of Y-shaped carbon nanofibers has been discussed and a possible growth model of Y-shaped carbon nanofibers has been proposed.

  18. Development and characterization of cefazolin loaded zinc oxide nanoparticles composite gelatin nanofiber mats for postoperative surgical wounds

    International Nuclear Information System (INIS)

    Rath, Goutam; Hussain, Taqadus; Chauhan, Gaurav; Garg, Tarun; Goyal, Amit Kumar

    2016-01-01

    Systemic antibiotic therapy in post-operative wound care remain controversial leading to escalation in levels of multi-resistant bacteria with unwanted morbidity and mortality. Recently zinc (Zn) because of multiple biophysiological functions, gain considerable interest for wound care. Based on our current understanding, the present study was designed with an intent to produce improve therapeutic approaches for post-operative wound management using composite multi-functional antibiotic carrier. The study involved the fabrication, characterization and pre-clinical evaluation of cefazolin nanofiber mats loaded with zinc oxide (ZnO) and comparing co-formulated mats with individual component, enable a side by side comparison of the benefits of our intervention. Minimum inhibitory concentration (MIC) of the drug, ZnO nanoparticles (ZnONPs) and drug-ZnONP mixture against Staphylococcus aureus was determined using micro dilution assay. The fabricated nanofibers were then evaluated for in-vitro antimicrobial activity and the mechanism of inhibition was predicted by scanning electron microscopy (SEM). Further these nanofiber mats were evaluated in-vivo for wound healing efficacy in Wistar rats. Study revealed that the average diameter of the nanofibers is around 200–900 nm with high entrapment efficiency and display sustained drug release behavior. The combination of ZnO and cefazolin in 1:1 weight ratio showed higher anti-bacterial activity of 1.9 ± 0.2 μg/ml. Transmission electron microscopy of bacterial cells taken from the zone of inhibition revealed the phenomenon of cell lysis in tested combination related to cell wall disruption. Further composite medicated nanofiber mats showed an accelerated wound healing as compared to plain cefazolin and ZnONP loaded mats. Macroscopical and histological evaluations demonstrated that ZnONP hybrid cefazolin nanofiber showed enhanced cell adhesion, epithelial migration, leading to faster and more efficient collagen synthesis

  19. Cellulose nanofibers/reduced graphene oxide flexible transparent conductive paper.

    Science.gov (United States)

    Gao, Kezheng; Shao, Ziqiang; Wu, Xue; Wang, Xi; Li, Jia; Zhang, Yunhua; Wang, Wenjun; Wang, Feijun

    2013-08-14

    The cellulose nanofibers (CNFs) paper exhibit high visible light transmittance, high mechanical strength, and excellent flexibility. Therefore, CNFs paper may be an excellent substrate material for flexible transparent electronic devices. In this paper, we endeavor to prepare CNFs-based flexible transparent conductive paper by layer-by-layer (LbL) assembly using divalent copper ions (Cu(2+)) as the crosslinking agent. The thickness of the reduced graphene oxide (RGO) active layer in the CNFs paper can be controlled by the cycle times of the LbL assembly. CNFs/[RGO]20 paper has the sheet resistances of ∼2.5 kΩ/□, and the transmittance of about 76% at a wavelength of 550 nm. Furthermore, CNFs/[RGO]20 paper inherits the excellent mechanical properties of CNFs paper, and the ultimate strength is about 136 MPa. CNFs-based flexible transparent conductive paper also exhibits excellent electrical stability and flexibility. Copyright © 2013. Published by Elsevier Ltd.

  20. Electrospun Nanofibers: New Concepts, Materials, and Applications.

    Science.gov (United States)

    Xue, Jiajia; Xie, Jingwei; Liu, Wenying; Xia, Younan

    2017-08-15

    Electrospinning is a simple and versatile technique that relies on the electrostatic repulsion between surface charges to continuously draw nanofibers from a viscoelastic fluid. It has been applied to successfully produce nanofibers, with diameters down to tens of nanometers, from a rich variety of materials, including polymers, ceramics, small molecules, and their combinations. In addition to solid nanofibers with a smooth surface, electrospinning has also been adapted to generate nanofibers with a number of secondary structures, including those characterized by a porous, hollow, or core-sheath structure. The surface and/or interior of such nanofibers can be further functionalized with molecular species or nanoparticles during or after an electrospinning process. In addition, electrospun nanofibers can be assembled into ordered arrays or hierarchical structures by manipulation of their alignment, stacking, and/or folding. All of these attributes make electrospun nanofibers well-suited for a broad spectrum of applications, including those related to air filtration, water purification, heterogeneous catalysis, environmental protection, smart textiles, surface coating, energy harvesting/conversion/storage, encapsulation of bioactive species, drug delivery, tissue engineering, and regenerative medicine. Over the past 15 years, our group has extensively explored the use of electrospun nanofibers for a range of applications. Here we mainly focus on two examples: (i) use of ceramic nanofibers as catalytic supports for noble-metal nanoparticles and (ii) exploration of polymeric nanofibers as scaffolding materials for tissue regeneration. Because of their high porosity, high surface area to volume ratio, well-controlled composition, and good thermal stability, nonwoven membranes made of ceramic nanofibers are terrific supports for catalysts based on noble-metal nanoparticles. We have investigated the use of ceramic nanofibers made of various oxides, including SiO 2 , TiO 2

  1. Carbon nanofibers obtained from electrospinning process

    Science.gov (United States)

    Bovi de Oliveira, Juliana; Müller Guerrini, Lília; Sizuka Oishi, Silvia; Rogerio de Oliveira Hein, Luis; dos Santos Conejo, Luíza; Cerqueira Rezende, Mirabel; Cocchieri Botelho, Edson

    2018-02-01

    In recent years, reinforcements consisting of carbon nanostructures, such as carbon nanotubes, fullerenes, graphenes, and carbon nanofibers have received significant attention due mainly to their chemical inertness and good mechanical, electrical and thermal properties. Since carbon nanofibers comprise a continuous reinforcing with high specific surface area, associated with the fact that they can be obtained at a low cost and in a large amount, they have shown to be advantageous compared to traditional carbon nanotubes. The main objective of this work is the processing of carbon nanofibers, using polyacrylonitrile (PAN) as a precursor, obtained by the electrospinning process via polymer solution, with subsequent use for airspace applications as reinforcement in polymer composites. In this work, firstly PAN nanofibers were produced by electrospinning with diameters in the range of (375 ± 85) nm, using a dimethylformamide solution. Using a furnace, the PAN nanofiber was converted into carbon nanofiber. Morphologies and structures of PAN and carbon nanofibers were investigated by scanning electron microscopy, Raman Spectroscopy, thermogravimetric analyses and differential scanning calorimeter. The resulting residual weight after carbonization was approximately 38% in weight, with a diameters reduction of 50%, and the same showed a carbon yield of 25%. From the analysis of the crystalline structure of the carbonized material, it was found that the material presented a disordered structure.

  2. Biofunctionalized Nanofibers Using Arthrospira (Spirulina Biomass and Biopolymer

    Directory of Open Access Journals (Sweden)

    Michele Greque de Morais

    2015-01-01

    Full Text Available Electrospun nanofibers composed of polymers have been extensively researched because of their scientific and technical applications. Commercially available polyhydroxybutyrate (PHB and polyhydroxybutyrate-co-valerate (PHB-HV copolymers are good choices for such nanofibers. We used a highly integrated method, by adjusting the properties of the spinning solutions, where the cyanophyte Arthrospira (formally Spirulina was the single source for nanofiber biofunctionalization. We investigated nanofibers using PHB extracted from Spirulina and the bacteria Cupriavidus necator and compared the nanofibers to those made from commercially available PHB and PHB-HV. Our study assessed nanofiber formation and their selected thermal, mechanical, and optical properties. We found that nanofibers produced from Spirulina PHB and biofunctionalized with Spirulina biomass exhibited properties which were equal to or better than nanofibers made with commercially available PHB or PHB-HV. Our methodology is highly promising for nanofiber production and biofunctionalization and can be used in many industrial and life science applications.

  3. Adhesion and metabolic activity of human corneal cells on PCL based nanofiber matrices

    Energy Technology Data Exchange (ETDEWEB)

    Stafiej, Piotr; Küng, Florian [Department of Ophthalmology, Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054 Erlangen (Germany); Institute of Polymer Materials, Universität Erlangen-Nürnberg, Martensstraße 7, 91054 Erlangen (Germany); Thieme, Daniel; Czugala, Marta; Kruse, Friedrich E. [Department of Ophthalmology, Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054 Erlangen (Germany); Schubert, Dirk W. [Institute of Polymer Materials, Universität Erlangen-Nürnberg, Martensstraße 7, 91054 Erlangen (Germany); Fuchsluger, Thomas A., E-mail: thomas.fuchsluger@uk-erlangen.de [Department of Ophthalmology, Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054 Erlangen (Germany)

    2017-02-01

    Confluent cell sheets were obtained on all nanofiber matrices.

  4. Electrical Impedance Measurements of PZT Nanofiber Sensors

    Directory of Open Access Journals (Sweden)

    Richard Galos

    2017-01-01

    Full Text Available Electrical impedance measurements of PZT nanofiber sensors were performed using a variety of methods over a frequency spectrum ranging from DC to 1.8 GHz. The nanofibers formed by electrospinning with diameters ranging from 10 to 150 nm were collected and integrated into sensors using microfabrication techniques. Special matching circuits with ultrahigh input impedance were fabricated to produce low noise, measurable sensor outputs. Material properties including resistivity and dielectric constant are derived from the impedance measurements. The resulting material properties are also compared with those of individual nanofibers being tested using conductive AFM and Scanning Conductive Microscopy.

  5. Advancement in organic nanofiber based transistors

    DEFF Research Database (Denmark)

    Jensen, Per Baunegaard With; Kjelstrup-Hansen, Jakob; Tavares, Luciana

    and characterization of OLETs using the organic semiconductors para-hexaphenylene (p6P), 5,5´-Di-4-biphenyl-2,2´-bithiophene (PPTTPP) and 5,5'-bis(naphth-2-yl)-2,2'-bithiophene (NaT2). These molecules can self-assemble forming molecular crystalline nanofibers. Organic nanofibers can form the basis for light......The focus of this project is to study the light emission from nanofiber based organic light-emitting transistors (OLETs) with the overall aim of developing efficient, nanoscale light sources with different colors integrated on-chip. The research performed here regards the fabrication...

  6. Polyaniline nanofiber/large mesoporous carbon composites as electrode materials for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Huan; Xu, Bin; Jia, Mengqiu, E-mail: jiamq@mail.buct.edu.cn; Zhang, Mei; Cao, Bin; Zhao, Xiaonan; Wang, Yu

    2015-03-30

    Highlights: • The composites of polyaniline nanofiber and large mesoporous carbon were prepared for supercapacitors. • The large mesoporous carbons were simply prepared by nano-CaCO{sub 3} template method. • The composites exhibit high capacitance and good rate capability and cycle stability. - Abstract: A composite of polyaniline nanofiber/large mesoporous carbon (PANI-F/LMC) hybrid was prepared by an in situ chemical oxidative polymerization of aniline monomer with nano-CaCO{sub 3} templated LMC as host matrix for supercapacitors. The morphology, composition and electronic structure of the composites (PANI-F/LMC) together with pure PANI nanofibers and the LMC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found that the PANI nanofibers were incorporated into the large mesochannels of LMC with interpenetrating framework formed. Such unique structure endows the PANI-F/LMC composite with a high capacitance of 473 F g{sup −1} at a current load of 0.1 A g{sup −1} with good rate performance and cycling stability, suggesting its potential application in the electrode material for supercapacitors.

  7. Polyaniline nanofiber/large mesoporous carbon composites as electrode materials for supercapacitors

    International Nuclear Information System (INIS)

    Liu, Huan; Xu, Bin; Jia, Mengqiu; Zhang, Mei; Cao, Bin; Zhao, Xiaonan; Wang, Yu

    2015-01-01

    Highlights: • The composites of polyaniline nanofiber and large mesoporous carbon were prepared for supercapacitors. • The large mesoporous carbons were simply prepared by nano-CaCO 3 template method. • The composites exhibit high capacitance and good rate capability and cycle stability. - Abstract: A composite of polyaniline nanofiber/large mesoporous carbon (PANI-F/LMC) hybrid was prepared by an in situ chemical oxidative polymerization of aniline monomer with nano-CaCO 3 templated LMC as host matrix for supercapacitors. The morphology, composition and electronic structure of the composites (PANI-F/LMC) together with pure PANI nanofibers and the LMC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found that the PANI nanofibers were incorporated into the large mesochannels of LMC with interpenetrating framework formed. Such unique structure endows the PANI-F/LMC composite with a high capacitance of 473 F g −1 at a current load of 0.1 A g −1 with good rate performance and cycling stability, suggesting its potential application in the electrode material for supercapacitors

  8. Synthesis, characterization and photocatalytic performance of SnS nanofibers and SnSe nanofibers derived from the electrospinning-made SnO{sub 2} nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Li; Li, Dan; Dong, Xiangting; Ma, Qianli; Yu, Wensheng; Wang, Xinlu; Yu, Hui; Wang, Jinxian; Liu, Guixia, E-mail: dongxiangting888@163.com [Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun (China)

    2017-11-15

    SnO{sub 2} nanofibers were fabricated by calcination of the electrospun PVP/SnCl{sub 4} composite nanofibers. For the first time, SnS nanofibers and SnSe nanofibers were successfully synthesized by double crucible sulfurization and selenidation methods via inheriting the morphology of SnO{sub 2} nanofibers used as precursors, respectively. X-ray diffraction (XRD) analysis shows SnS nanofibers and SnSe nanofibers are respectively pure orthorhombic phase with space group of Pbnm and Cmcm. Scanning electron microscope (SEM) observation indicates that the diameters of SnS nanofibers and SnSe nanofibers are respectively 140.54±12.80 nm and 96.52±14.17 nm under the 95 % confidence level. The photocatalytic activities of samples were studied by using rhodamine B (Rh B) as degradation agent. When SnS or SnSe nanofibers are employed as the photocatalysts, the respective degradation rates of Rh B solution under the ultraviolet light irradiation after 200 min irradiation are 92.55 % and 92.86 %. The photocatalytic mechanism and formation process of SnS and SnSe nanofibers are also provided. More importantly, this preparation technique is of universal significance to prepare other metal chalcogenides nanofibers. (author)

  9. Polyurethane nanofibers containing copper nanoparticles as future materials

    DEFF Research Database (Denmark)

    Sheikh, Faheem A.; Kanjwal, Muzafar Ahmed; Saran, Saurabh

    2011-01-01

    nanofibers. Typically, a colloidal gel consisting of copper NPs and polyurethane has been electrospun. SEM-EDX and TEM results confirmed well oriented nanofibers and good dispersion of pure copper NPs. Copper NPs have diameter in the range of 5–10nm. The thermal stability of the synthesized nanofibers...... the antimicrobial efficacy of these nanofiber mats. Subsequently, antimicrobial tests have indicated that the prepared nanofibers do posses good bactericidal effect. Accordingly, it is noted that the obtained nanofiber mats can be used as future filter membranes with good antimicrobial activities....

  10. Electrospun Nanofibers: Solving Global Issues

    Science.gov (United States)

    Si, Yang; Tang, Xiaomin; Yu, Jianyong; Ding, Bin

    Energy and environment will head the list of top global issues facing society for the next 50 years. Nanotechnology is responding to these challenges by designing and fabricating functional nanofibers optimized for energy and environmental applications. The route toward these nano-objects is based primarily on electrospinning: a highly versatile method that allows the fabrication of continuous fibers with diameters down to a few nanometers. The mechanism responsible for the fiber formation mainly includes the Taylor Cone theory and flight-instability theory, which can be predicted theoretically and controlled experimentally. Moreover, the electrospinning has been applied to natural polymers, synthetic polymers, ceramics, and carbon. Fibers with complex architectures, such as ribbon fiber, porous fiber, core-shell fiber, or hollow fiber, can be produced by special electrospinning methods. It is also possible to produce nanofibrous membranes with designed aggregate structure including alignment, patterning, and two-dimensional nanonets. Finally, the brief analysis of nanofibers used for advanced energy and environmental applications in the past decade indicates that their impact has been realized well and is encouraging, and will continually represent a key technology to ensure sustainable energy and preserve our environment for the future.

  11. RGO/InVO{sub 4} hollowed-out nanofibers: Electrospinning synthesis and its application in photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Dong [Key Lab of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); College of Resource and Environment, Qingdao Agricultural University, Qingdao 266109 (China); Zhang, Yanxiang [College of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Gao, Mengchun, E-mail: mengchungao@outlook.com [Key Lab of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); Xin, Yanjun; Wu, Juan [College of Resource and Environment, Qingdao Agricultural University, Qingdao 266109 (China); Bao, Nan [College of Environmental Science and Engineering, Shandong University, Jinan 250100 (China)

    2015-10-30

    Graphical abstract: - Highlights: • RGO/InVO{sub 4} hollow-out nanofibers were obtained by electrospinning method. • The properties of InVO{sub 4} hollow-out nanofibers were deeply influenced by RGO. • RGO could reduce recombination of e{sup −}–h{sup +} pairs to improve photocatalytic activity. • Photo-induced h{sup +} and e{sup −} are the two main reactive species for RhB degradation. - Abstract: A composite of reduced graphene oxide (RGO) and InVO{sub 4} nanofiber was successfully synthesized by an electrospinning technique. The as-collected fibers were calcined at 420 °C in air and then calcined at 550 °C in nitrogen gas to remove polyvinyl pyrrolidone (PVP), which could enable InVO{sub 4} to crystallize and protect the RGO from oxidation. The InVO{sub 4} in the composite illustrated a hollowed-out fibrous morphology and orthorhombic phase, and RGO nanosheets were nested in the InVO{sub 4} nanofibers. The hybrid RGO could produce more hydroxyl groups and a higher oxygen vacancy density on the surface of RGO/InVO{sub 4} composite. Compared with pure InVO{sub 4}, the light absorption range of the as-prepared RGO/InVO{sub 4} composite was expanded. In Rh B degradation, the RGO/InVO{sub 4} hybrid nanofibers displayed a higher photocatalytic activity than pure InVO{sub 4} nanofibers. The enhanced photocatalytic activity might be ascribed to the role of RGO as an electron transporter and acceptor in the composite, which could effectively inhibit the charge recombination and facilitate the charge transfer. The exported electron could attack an O{sub 2} molecule to facilitate the generation of • O{sub 2}{sup −} and • OH for the photodegradation process of Rh B.

  12. Enhanced cell mitochondrial activity using electrospun nanofibers

    CSIR Research Space (South Africa)

    Jacobs, V

    2015-06-01

    Full Text Available Research in tissue engineering related to the improved processes using nanofiber scaffolds has seen considerable progress in the last decade in the regeneration and construction of a number of artificial tissue types. These designs are generally...

  13. Thermal conductivity of electrospun polyethylene nanofibers.

    Science.gov (United States)

    Ma, Jian; Zhang, Qian; Mayo, Anthony; Ni, Zhonghua; Yi, Hong; Chen, Yunfei; Mu, Richard; Bellan, Leon M; Li, Deyu

    2015-10-28

    We report on the structure-thermal transport property relation of individual polyethylene nanofibers fabricated by electrospinning with different deposition parameters. Measurement results show that the nanofiber thermal conductivity depends on the electric field used in the electrospinning process, with a general trend of higher thermal conductivity for fibers prepared with stronger electric field. Nanofibers produced at a 45 kV electrospinning voltage and a 150 mm needle-collector distance could have a thermal conductivity of up to 9.3 W m(-1) K(-1), over 20 times higher than the typical bulk value. Micro-Raman characterization suggests that the enhanced thermal conductivity is due to the highly oriented polymer chains and enhanced crystallinity in the electrospun nanofibers.

  14. Melt sonoquenching: an affective process to obtain new hybrid material and achieve enhanced electrochromic performances based on V{sub 2}O{sub 5}/2,4,5-tris(1-methyl- 4-pyridinium)-imidazolide tetrafluoroborate nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Renato S. de; Goulart, Juliana da S.; Miranda, Fabio S.; Ponzio, Eduardo A., E-mail: eaponzio@vm.uff.br [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Instituto de Quimica

    2014-03-15

    Hybrid electrochromic materials are a very important class of compounds, because they enable new and/or better optical and electrochemical properties to be unfolded. This paper reports the synthesis of the new V{sub 2}O{sub 5}.1.26H{sub 2}O([C{sub 3}N{sub 2}(C{sub 6}H{sub 7}N){sub 3}]){sub 0.07} using the combination of two traditional methods, melting quenching and sonochemistry. The new material was characterized by several methods in order to verify the physical and chemical characteristics and its possible use as an electrochromic electrode. The organic guest provokes an interlayer spacing decrease of the inorganic matrix and the electrostatic interaction between the oxo groups of the V{sub 2}O{sub 5} matrix and the pyridinium rings of the organic guest demonstrate a strong interaction. The new hybrid nanostructure presented good reversibility and cyclability during 50 cycles, electrochromic efficiency of 22 cm{sup 2} C{sup -1} (410 nm) and 96 % color retention after 50 cycles of color changing. (author)'.

  15. Fabrication of Conductive Polypyrrole Nanofibers by Electrospinning

    Directory of Open Access Journals (Sweden)

    Yiqun Cong

    2013-01-01

    Full Text Available Electrospinning is employed to prepare conductive polypyrrole nanofibers with uniform morphology and good mechanical strength. Soluble PPy was synthesized with NaDEHS as dopant and then applied to electrospinning with or without PEO as carrier. The PEO contents had great influence on the morphology and conductivity of the electrospun material. The results of these experiments will allow us to have a better understanding of PPy electrospun nanofibers and will permit the design of effective electrodes in the BMIs fields.

  16. Chlamydia - CDC Fact Sheet

    Science.gov (United States)

    ... Archive STDs Home Page Bacterial Vaginosis (BV) Chlamydia Gonorrhea Genital Herpes Hepatitis HIV/AIDS & STDs Human Papillomavirus ( ... sheet Pelvic Inflammatory Disease (PID) – CDC fact sheet Gonorrhea – CDC fact sheet STDs Home Page Bacterial Vaginosis ( ...

  17. Fabrication and characterization of PVA/Gum tragacanth/PCL hybrid nanofibrous scaffolds for skin substitutes.

    Science.gov (United States)

    Zarekhalili, Zahra; Bahrami, S Hajir; Ranjbar-Mohammadi, M; Milan, Peiman Brouki

    2017-01-01

    In this work three dimensional biodegradable nanofiberous scaffolds containing poly(ε-caprolactone) (PCL), poly(vinyl alcohol) (PVA) and gum tragacanth (GT) were successfully fabricated through two nozzles electrospinning process. For this purpose, PVA/GT blend (Blend: B) solution (60:40wt%) was injected from one syringe and poly(ε-caprolactone) solution from the other one. Presence of PVA and PCL in the formulation improved the electrospinning process of GT solution and mechanical properties of the fabricated nanofibers. Scanning electron microscopy (SEM) results showed uniform PVA/GT-PCL blend-hybrid (Blend-Hybrid: B-H) nanofibers with the diameter ranging about 132±27nm. Hybrid nanofibers were evaluated by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) tests. The antibacterial activities of the PVA/GT-PCL (B-H) nanofibers were conducted against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus and results indicated that the hybrid nanofibers were 95.19% antibacterial against S. aureus bacterium. NIH 3T3 fibroblast cells growth and MTT assay were carried out on the scaffolds. Hydrophilicity nature, favorable mechanical properties of the fabricated hybrid nanofibers, along with their structure in biological media, biocompatibility, as well as antibacterial property indicate scaffolds prepared are suitable for tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. FY 2000 report on the results of the development of technology for commercialization of the photovoltaic power system - Development of production technology of thin film solar cells. Development of production technology of application type new structure thin film solar cells (Development of production technology of high efficiency hybrid thin films/sheet solar cells); 2000 nendo New sunshine keikaku seika hokokusho. Taiyoko hatsuden system jitsuyoka gijutsu kaihatsu, Hakumaku taiyodenchi no seizo gijutsu kaihatsu, Oyogata shinkozo hakumaku taiyodenchi no seizo gijutsu kaihatsu, (Kokoritsu hybrid gata hakumaku / sheet taiyodenchi no seizo gijutsu kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    For the purpose of realizing low cost and high efficiency hybrid thin films/sheet solar cells, the R and D were carried out, and the FY 2000 results were reported. As to the formation technology of the upper cell, the following technologies were developed and the results contributory to the heightening of efficiency were obtained: technology for improvement of cell characteristics by gap widening of p layer, technology for optimization of formation conditions of i layer corresponding to the hybrid solar cell, technology for heightening of current by the intermediate ZnO layer just under the upper cell. Relating to the development of formation technology of high quality microcrystal thin films, it was indicated that the microcrystal silicon thin film had the conformity effective also for polycrystal silicon, and at the same time, the conversion efficiency of 12.8% and release voltage of 0.579V were obtained by the cell using the cast polycrystal board. In the thin film/polycrystal sheet hybrid solar cell in which all these technologies were integrated, the conversion efficiency of 12.0% was achieved, and the possibility was verified of achieving the target efficiency of 14% by further improvement of FF. (NEDO)

  19. Surface structure enhanced second harmonic generation in organic nanofibers

    DEFF Research Database (Denmark)

    Fiutowski, Jacek; Maibohm, Christian; Kostiučenko, Oksana

    Second-harmonic generation upon femto-second laser irradiation of nonlinearly optically active nanofibers grown from nonsymmetrically functionalized para-quarterphenylene (CNHP4) molecules is investigated. Following growth on mica templates, the nanofibers have been transferred onto lithography...

  20. Field-enhanced nonlinear optical properties of organic nanofibers

    DEFF Research Database (Denmark)

    Kostiučenko, Oksana; Fiutowski, Jacek; Brewer, Jonathan R.

    2014-01-01

    Second harmonic generation in nonlinearly optically active organic nanofibers, generated via self-assembled surface growth from nonsymmetrically functionalized para-quarterphenylene (CNHP4) molecules, has been investigated. After the growth on mica templates, nanofibers have been transferred onto...

  1. GASN sheets

    International Nuclear Information System (INIS)

    2013-12-01

    This document gathers around 50 detailed sheets which describe and present various aspects, data and information related to the nuclear sector or, more generally to energy. The following items are addressed: natural and artificial radioactive environment, evolution of energy needs in the world, radioactive wastes, which energy for France tomorrow, the consequences in France of the Chernobyl accident, ammunitions containing depleted uranium, processing and recycling of used nuclear fuel, transport of radioactive materials, seismic risk for the basic nuclear installations, radon, the precautionary principle, the issue of low doses, the EPR, the greenhouse effect, the Oklo nuclear reactors, ITER on the way towards fusion reactors, simulation and nuclear deterrence, crisis management in the nuclear field, does nuclear research put a break on the development of renewable energies by monopolizing funding, nuclear safety and security, the plutonium, generation IV reactors, comparison of different modes of electricity production, medical exposure to ionizing radiations, the control of nuclear activities, food preservation by ionization, photovoltaic solar collectors, the Polonium 210, the dismantling of nuclear installations, wind energy, desalination and nuclear reactors, from non-communication to transparency about nuclear safety, the Jules Horowitz reactor, CO 2 capture and storage, hydrogen, solar energy, the radium, the subcontractors of maintenance of the nuclear fleet, biomass, internal radio-contamination, epidemiological studies, submarine nuclear propulsion, sea energy, the Three Mile Island accident, the Chernobyl accident, the Fukushima accident, the nuclear after Fukushima

  2. Hybrid Nanostructures Containing Sulfadiazine Modified Chitosan as Antimicrobial Drug Carriers

    Directory of Open Access Journals (Sweden)

    Bogdanel Silvestru Munteanu

    2016-11-01

    Full Text Available Chitosan (CH nanofibrous structures containing sulfadiazine (SDZ or sulfadiazine modified chitosan (SCH in the form of functional nanoparticles attached to nanofibers (hybrid nanostructures were obtained by mono-axial and coaxial electrospinning. The mono-axial design consisted of a SDZ/CH mixture solution fed through a single nozzle while the coaxial design consisted of SCH and CH solutions separately supplied to the inner and outer nozzle (or in reverse order. The CH ability to form nanofibers assured the formation of a nanofiber mesh, while SDZ and SCH, both in form of suspensions in the electrospun solution, assured the formation of active nanoparticles which remained attached to the CH nanofiber mesh after the electrospinning process. The obtained nanostructures were morphologically characterized by scanning electron microscopy (SEM and atomic force microscopy (AFM. The SDZ release profiles and kinetics were analyzed. The SDZ or SCH nanoparticles loosely attached at the surface of the nanofibers, provide a burst release in the first 20 min, which is important to stop the possible initial infection in a wound, while the SDZ and SCH from the nanoparticles which are better confined (or even encapsulated into the CH nanofibers would be slowly released with the erosion/disruption of the CH nanofiber mesh.

  3. Obtaining nanofibers from sisal to reinforce nanocomposites biodegradable matrixes

    International Nuclear Information System (INIS)

    Oliveira, Francieli B. de; Teixeira, Eliangela de M.; Marconcini, Jose M.; Mattoso, Luiz H.C.; Teodoro, Kelcilene B.R.

    2009-01-01

    Cellulose nanofibers have been extracted by acid hydrolysis from sisal fibers. They are seen a good source material due to availability and low cost. The nanofibers was evaluated by thermal degradation behavior using thermogravimetry (TG), crystallinity by X-ray diffraction and morphological structure was investigated by atomic force microscopy (AFM) experiments. The resulting nanofibers was shown high crystallinity and a network of rodlike cellulose elements. The nanofibers will be incorporated as reinforcement in a biodegradable matrix and evaluated. (author)

  4. Hybrid Electric Vehicle Publications | Transportation Research | NREL

    Science.gov (United States)

    Hybrid Electric Vehicle Publications Hybrid Electric Vehicle Publications The following technical papers, conference papers, and fact sheets provide information about NREL's hybrid electric fleet vehicle Class 8 Hybrid Electric Delivery Trucks. Mike Lammert. (2011) FedEx Delivery Trucks In-Use and Vehicle

  5. Polycaprolactone-templated reduced-graphene oxide liquid crystal nanofibers towards biomedical applications

    DEFF Research Database (Denmark)

    Jalili-Firoozinezhad, Sasan; Hasan Mohamadzadeh Moghadam, Mohamad; Ghanian, Mohammad Hossein

    2017-01-01

    Here, we report a facile method to generate electrically conductive nanofibers by coating and subsequently chemically reducing graphene oxide (GO) liquid crystals on a polycaprolactone (PCL) mat. Ultra large GO sheets obtained are in favor of charge carrier mobility and oriented morphology...... of the GO coating. We showed that coating the reduced GO (rGO) not only retains the three-dimensional topography, fiber orientation and size of the template PCL, but also makes it electroconductive. Our preliminary in vitro assessments using mesenchymal stem cells revealed no induced cytotoxicity yet...... increased cellular metabolism on PCL-templated rGO fibers....

  6. Electrodeposited nickel-cobalt sulfide nanosheet on polyacrylonitrile nanofibers: a binder-free electrode for flexible supercapacitors

    Science.gov (United States)

    Kamran Sami, Syed; Siddiqui, Saqib; Tajmeel Feroze, Muhammad; Chung, Chan-Hwa

    2017-11-01

    To pursue high-performance energy storage devices with both high energy density and power density, one-dimensional (1D) nanostructures play a key role in the development of functional devices including energy conversion, energy storage, and environmental devices. The polyacrylonitrile (PAN) nanofibers were obtained by the versatile electrospinning method. An ultra-thin nickel-cobalt sulfide (NiCoS) layer was conformably electrodeposited on a self-standing PAN nanofibers by cyclic voltammetry to fabricate the light-weighted porous electrodes for supercapacitors. The porous web of PAN nanofibers acts as a high-surface-area scaffold with significant electrochemical performance, while the electrodeposition of metal sulfide nanosheet further enhances the specific capacitance. The fabricated NiCoS on PAN (NiCoS/PAN) nanofibers exhibits a very high capacitance of 1513 F g-1 at 5 A g-1 in 1 M potassium chloride (KCl) aqueous electrolyte with superior rate capability and excellent electrochemical stability as a hybrid electrode. The high capacitance of the NiCoS is attributed to the large surface area of the electrospun PAN nanofibers scaffold, which has offered a large number of active sites for possible redox reaction of ultra-thin NiCoS layer. Benefiting from the compositional features and electrode architectures, the hybrid electrode of NiCoS/PAN nanofibers shows greatly improved electrochemical performance with an ultra-high capacitance (1124 F g-1 at 50 A g-1). Moreover, a binder-free asymmetric supercapacitor device is also fabricated by using NiCoS/PAN nanofibers as the positive electrode and activated carbon (MSP-20) on PAN nanofibers as the negative electrode; this demonstrates high energy density of 56.904 W h kg-1 at a power density of 1.445 kW kg-1, and it still delivers the energy density of 33.3923 W h kg-1 even at higher power density of 16.5013 kW kg-1.

  7. Evaluation of morphology and cell behaviour of a novel synthesized electrospun poly(vinyl pyrrolidone/poly(vinyl alcohol/hydroxyapatite nanofibers

    Directory of Open Access Journals (Sweden)

    Raheleh Faridi-Majidi

    2017-04-01

    Full Text Available Objective(s: Three-dimensional structures such as nanofibrous scaffolds are being used in biomedical engineering as well as provide a site for cells to attach and proliferate leading to tissue formation. In the present study, poly(vinyl pyrrolidone (PVP/ poly(vinyl alcohol(PVA hybrid nanofibrous scaffold was synthesized by electrospinning. Materials and Methods: The effect of adding nano hydroxyapatite (n-HA and also Epoxypropoxy-propyl-trimethoxysilane (EPPTMS as a crosslinking agent on morphology and cell behaviour of the nanofibers was investigated.Results: Scanning electron microscope (SEM observations showed that all kinds of nanofibers represented uniform and well-ordered morphologies without formation of any beads by controlling the synthesis parameters. The average ûber diameter of PVP-PVA was 260 nm. n-HA was synthesized by wet chemical process. The synthesized n-HA was characterized by XRD for structural analysis. Transmission electron microscope (TEM revealed that HA particles had nanosized dimensions (in the range of 40-100 nm. The presence of n-HA within electrospun PVP-PVA nanofibers was confirmed by XRD and Fourier transmission infrared spectroscopy (FTIR analyses. The average ûber diameter was decreased to 136 nm when n-HA was added in the composition of PVP-PVA. FTIR analysis depicted that PVP-PVA nanofibers were linked to EPPTMS as a biocompatible material by the covalent bond. Although adding n-HA caused to decrease the diameter of PVP-PVA nanofibers, addition of EPPTMS within PVP/PVA/n-HA nanofibers induced increasing distribution of fiber diameter as it enhanced to 195nm. In addition, the proper proliferation of G292 osteoblastic cells without any cytotoxicity was observed for the nanofiber.Conclusion: Since these materials have been known as biomaterials, PVP/PVA/n-HA-EPPTMS nanofibers can be propounded as a good candidate for bone tissue engineering application.

  8. PLGA nanofibers blended with designer self-assembling peptides for peripheral neural regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Nune, Manasa; Krishnan, Uma Maheswari; Sethuraman, Swaminathan, E-mail: swami@sastra.edu

    2016-05-01

    Electrospun nanofibers are attractive candidates for neural regeneration due to similarity to the extracellular matrix. Several synthetic polymers have been used but they lack in providing the essential biorecognition motifs on their surfaces. Self-assembling peptide nanofiber scaffolds (SAPNFs) like RADA16 and recently, designer SAPs with functional motifs RADA16-I-BMHP1 areexamples, which showed successful spinal cord regeneration. But these peptide nanofiber scaffolds have poor mechanical properties and faster degradation rates that limit their use for larger nerve defects. Hence, we have developed a novel hybrid nanofiber scaffold of polymer poly(L-lactide-co-glycolide) (PLGA) and RADA16-I-BMHP1. The scaffolds were characterized for the presence of peptides both qualitatively and quantitatively using several techniques like SEM, EDX, FTIR, CHN analysis, Circular Dichroism analysis, Confocal and thermal analysis. Peptide self-assembly was retained post-electrospinning and formed rod-like nanostructures on PLGA nanofibers. In vitro cell compatibility was studied using rat Schwann cells and their adhesion, proliferation and gene expression levels on the designed scaffolds were evaluated. Our results have revealed the significant effects of the peptide blended scaffolds on promoting Schwann cell adhesion, extension and phenotypic expression. Neural development markers (SEM3F, NRP2 & PLX1) gene expression levels were significantly upregulated in peptide blended scaffolds compared to the PLGA scaffolds. Thus the hybrid blended novel designer scaffolds seem to be promising candidates for successful and functional regeneration of the peripheral nerve. - Highlights: • A novel blended scaffold of polymer PLGA and designer self-assembling peptide RADA16-I-BMPH1 was designed • The peptide retained the self-assembling features and formed rod like nanostructures on top of PLGA nanofibers • PLGA-peptide scaffolds have promoted the Schwann cell bipolar extension and

  9. Fabrication and Intermolecular Interactions of Silk Fibroin/Hydroxybutyl Chitosan Blended Nanofibers

    Directory of Open Access Journals (Sweden)

    Xiu-Mei Mo

    2011-03-01

    Full Text Available The native extracellular matrix (ECM is composed of a cross-linked porous network of multifibril collagens and glycosaminoglycans. Nanofibrous scaffolds of silk fibroin (SF and hydroxybutyl chitosan (HBC blends were fabricated using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP and trifluoroacetic acid (TFA as solvents to biomimic the native ECM via electrospinning. Scanning electronic microscope (SEM showed that relatively uniform nanofibers could be obtained when 12% SF was blended with 6% HBC at the weight ratio of 50:50. Meanwhile, the average nanofibrous diameter increased when the content of HBC in SF/HBC blends was raised from 20% to 100%. Fourier transform infrared spectra (FTIR and 13C nuclear magnetic resonance (NMR showed SF and HBC molecules existed in hydrogen bonding interactions but HBC did not induce conformation of SF transforming from random coil form to β-sheet structure. X-ray diffraction (XRD confirmed the different structure of SF/HBC blended nanofibers from both SF and HBC. Thermogravimetry-Differential thermogravimetry (TG-DTG results demonstrated that the thermal stability of SF/HBC blend nanofibrous scaffolds was improved. The results indicated that the rearrangement of HBC and SF molecular chain formed a new structure due to stronger hydrogen bonding between SF and HBC. These electrospun SF/HBC blended nanofibers may provide an ideal tissue engineering scaffold and wound dressing.

  10. Preparation and characterization of kefiran electrospun nanofibers.

    Science.gov (United States)

    Esnaashari, Seyedeh Sara; Rezaei, Sasan; Mirzaei, Esmaeil; Afshari, Hamed; Rezayat, Seyed Mahdi; Faridi-Majidi, Reza

    2014-09-01

    In this study, we report the first successful production of kefiran nanofibers through electrospinning process using distilled water as solvent. For this purpose, kefiran was extracted from cultured kefir grains, and homogenous kefiran solutions with different concentrations were prepared and then electrospun to obtain uniform nanofibers. The effect of main process parameters, including applied voltage, tip-to-collector distance, and feeding rate, on diameter and morphology of produced nanofibers, was studied. Scanning electron microscopy (SEM) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy were used to characterize electrospun mats. Rheological behavior of the kefiran solution was evaluated via a cone and plate rheometer too. The results exhibited that diameter of kefiran nanofibers increased with increasing polymer concentration, applied voltage, and polymer feeding rate, while tip-to-collector distance did not have significant effect on nanofiber diameter. ATR-FTIR spectra showed that kefiran has maintained its molecular structure during electrospinning process. Flow curves also demonstrated shear thinning behavior for kefiran solutions. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Cotton nanofibers obtained by different acid conditions

    International Nuclear Information System (INIS)

    Teixeira, Eliangela de M.; Oliveira, Caue Ribeiro de; Mattoso, Luiz H.C.; Correa, Ana Carolina; Palladin, Priscila

    2009-01-01

    The thermal stability of cellulose nanofibers is related to their application and especially to polymer processing which temperatures of processing are around 200 deg C. In this work, nanofibers of commercial cotton were obtained by acid hydrolysis employing different acids: sulfuric, hydrochloric and a mixture (2:1; sulfuric acid: hydrochloric acid).The morphology of the nanofibers were characterized by transmission microscopy (TEM), crystallinity by x-ray diffraction (XRD) and thermal stability in air atmosphere by thermogravimetric analysis (TGA). The results indicated a very similar morphology and crystallinity among them. The main differences were relative to aggregation state e and thermal stability. The aggregation state of the suspensions decreases in the order HCl 2 SO 4 :HCl 2 SO 4- . The hydrolysis with a mix of HCl and H 2 SO 4 resulted in cellulose nanofibers with higher thermal stability than those hydrolyzed with H 2 SO 4 . The hydrolysis employed with a mixture of sulphuric and hydrochloric acids also showed a better dispersion than those suspensions of nanofibers obtained by hydrolysis with only HCl. (author)

  12. PANI-nanofibers/polyethylene blends: preparation and properties

    International Nuclear Information System (INIS)

    Oliveira, F.; Hubler, R.; Basso, N.R.S.; Fim, F.C.; Galland, G.B.

    2010-01-01

    In this work polyaniline nanofibers (PANI-nanofibers) were prepared via interfacial polymerization. The PANI-nanofibers were dispersed in polyethylene (PE) matrix by in situ polymerization of ethylene using Cp 2 ZrCl 2 [bis(cyclopentadienyl) zirconium(IV) dichloride)] and methylaluminoxane as catalytic system. The composites were characterized by infra-red spectroscopy, X-ray diffraction, thermal analysis, transmission electron microscopy and scanning electron microscopy. The results show that nanofibers with average diameters of 200 nm were synthesized and that it was obtained well dispersed PE/PANI nanocomposites. The PANI-nanofibers load did not affect the catalytic activity, but it decreased crystallinity degree of nanocomposites. (author)

  13. Fabrication of nanofiber mats from electrospinning of functionalized polymers

    Science.gov (United States)

    Oktay, Burcu; Kayaman-Apohan, Nilhan; Erdem-Kuruca, Serap

    2014-08-01

    Electrospinning technique enabled us to prepare nanofibers from synthetic and natural polymers. In this study, it was aimed to fabricate electrospun poly(vinyl alcohol) (PVA) based nanofibers by reactive electrospinning process. To improve endurance of fiber toward to many solvents, PVA was functionalized with photo-crosslinkable groups before spinning. Afterward PVA was crosslinked by UV radiation during electrospinning process. The nanofiber mats were characterized by scanning electron microscopy (SEM). The results showed that homogenous, uniform and crosslinked PVA nanofibers in diameters of about 200 nm were obtained. Thermal stability of the nanofiber mat was investigated with thermal gravimetric analysis (TGA). Also the potential use of this nanofiber mats for tissue engineering was examined. Osteosarcoma (Saos) cells were cultured on the nanofiber mats.

  14. Fabrication of nanofiber mats from electrospinning of functionalized polymers

    International Nuclear Information System (INIS)

    Oktay, Burcu; Kayaman-Apohan, Nilhan; Erdem-Kuruca, Serap

    2014-01-01

    Electrospinning technique enabled us to prepare nanofibers from synthetic and natural polymers. In this study, it was aimed to fabricate electrospun poly(vinyl alcohol) (PVA) based nanofibers by reactive electrospinning process. To improve endurance of fiber toward to many solvents, PVA was functionalized with photo-crosslinkable groups before spinning. Afterward PVA was crosslinked by UV radiation during electrospinning process. The nanofiber mats were characterized by scanning electron microscopy (SEM). The results showed that homogenous, uniform and crosslinked PVA nanofibers in diameters of about 200 nm were obtained. Thermal stability of the nanofiber mat was investigated with thermal gravimetric analysis (TGA). Also the potential use of this nanofiber mats for tissue engineering was examined. Osteosarcoma (Saos) cells were cultured on the nanofiber mats

  15. Nano-Fiber Reinforced Enhancements in Composite Polymer Matrices

    Science.gov (United States)

    Chamis, Christos C.

    2009-01-01

    Nano-fibers are used to reinforce polymer matrices to enhance the matrix dependent properties that are subsequently used in conventional structural composites. A quasi isotropic configuration is used in arranging like nano-fibers through the thickness to ascertain equiaxial enhanced matrix behavior. The nano-fiber volume ratios are used to obtain the enhanced matrix strength properties for 0.01,0.03, and 0.05 nano-fiber volume rates. These enhanced nano-fiber matrices are used with conventional fiber volume ratios of 0.3 and 0.5 to obtain the composite properties. Results show that nano-fiber enhanced matrices of higher than 0.3 nano-fiber volume ratio are degrading the composite properties.

  16. Gas Sensing Properties of Indium Tin Oxide Nanofibers

    Directory of Open Access Journals (Sweden)

    Shiyou Xu

    2009-11-01

    Full Text Available Indium Tin Oxide (ITO nanofibers were fabricated by the electrospinning process. The morphology and crystal structure of ITO nanofibers were studied by SEM, XRD, and TEM respectively. The results showed that polycrystalline ITO nanofibers with an average diameter of 80 nm were obtained. Sensors based on these nanofibers were fabricated by collecting these nanofibers on the integrated sensor platforms. The ITO nanofiber-based sensors showed very fast and high sensor responses at both room and elevated temperatures for NO2. The ratios of resistance in NO2 over that in air were 5 at room temperature and 34 at the optimal working temperature, respectively. The ITO nanofiber-based sensor can be repeatedly used. The details for the fast, enhanced sensor responses and the optimal temperature were discussed.

  17. Bioactive self-assembled peptide nanofibers for corneal stroma regeneration.

    Science.gov (United States)

    Uzunalli, G; Soran, Z; Erkal, T S; Dagdas, Y S; Dinc, E; Hondur, A M; Bilgihan, K; Aydin, B; Guler, M O; Tekinay, A B

    2014-03-01

    Defects in the corneal stroma caused by trauma or diseases such as macular corneal dystrophy and keratoconus can be detrimental for vision. Development of therapeutic methods to enhance corneal regeneration is essential for treatment of these defects. This paper describes a bioactive peptide nanofiber scaffold system for corneal tissue regeneration. These nanofibers are formed by self-assembling peptide amphiphile molecules containing laminin and fibronectin inspired sequences. Human corneal keratocyte cells cultured on laminin-mimetic peptide nanofibers retained their characteristic morphology, and their proliferation was enhanced compared with cells cultured on fibronectin-mimetic nanofibers. When these nanofibers were used for damaged rabbit corneas, laminin-mimetic peptide nanofibers increased keratocyte migration and supported stroma regeneration. These results suggest that laminin-mimetic peptide nanofibers provide a promising injectable, synthetic scaffold system for cornea stroma regeneration. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  18. Development in fiscal 1999 of technologies to put photovoltaic power generation systems into practical use. Development of thin film solar cell manufacturing technologies (Development of technologies to manufacture applied type thin film solar cells with new structure and development of high-efficiency hybrid thin film/sheet solar cells); 1999 nendo taiyoko hatsuden system jitsuyoka gijutsu kaihatsu seika hokokusho. Usumaku taiyo denchi no seizo gijutsu kaihatsu (oyogata shin kozo usumaku taiyo denchi no seizo gijutsu kaihatsu (kokoritsu hybrid gata usumaku / sheet taiyo denchi no seizo gijutsu kaihatsu))

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    With an objective to develop low-cost and high-efficiency hybrid thin film/sheet solar cells, research and development has been performed. This paper summarizes the achievements in fiscal 1999. The research is related to a hybrid construction, in which the upper cells of amorphous silicon thin film are formed on the lower cells bonded with micro-crystalline silicon thin film relative to a poly-crystalline silicon sheet. In the technology to form the upper cells, a pin-construction using amorphous silicon thin film made by using the plasma CVD process was adopted, whereas an open circuit voltage of 1.45V, a short circuit current of 13.6 mA/cm{sup 2}, and a conversion efficiency of 13.5% were obtained. In the technology to form the substrate for the lower cells, formation of flat silicon thin plate that can be peeled off was identified as a result of adopting the construction in which a graphite substrate is provided on a rotating cooling body of 12-prism type. With regard to the technology to bond and form the lower cells, electrical properties of hetero-bonded cells were discussed, and an open circuit voltage of 0.605V and a conversion efficiency of 14.3% were obtained as a result of enhancing the film quality and optimizing the film thickness. (NEDO)

  19. Nanoparticles and nanofibers for topical drug delivery

    Science.gov (United States)

    Goyal, Ritu; Macri, Lauren K.; Kaplan, Hilton M.; Kohn, Joachim

    2016-01-01

    This review provides the first comprehensive overview of the use of both nanoparticles and nanofibers for topical drug delivery. Researchers have explored the use of nanotechnology, specifically nanoparticles and nanofibers, as drug delivery systems for topical and transdermal applications. This approach employs increased drug concentration in the carrier, in order to increase drug flux into and through the skin. Both nanoparticles and nanofibers can be used to deliver hydrophobic and hydrophilic drugs and are capable of controlled release for a prolonged period of time. The examples presented provide significant evidence that this area of research has—and will continue to have — a profound impact on both clinical outcomes and the development of new products. PMID:26518723

  20. Chitosan based nanofibers in bone tissue engineering.

    Science.gov (United States)

    Balagangadharan, K; Dhivya, S; Selvamurugan, N

    2017-11-01

    Bone tissue engineering involves biomaterials, cells and regulatory factors to make biosynthetic bone grafts with efficient mineralization for regeneration of fractured or damaged bones. Out of all the techniques available for scaffold preparation, electrospinning is given priority as it can fabricate nanostructures. Also, electrospun nanofibers possess unique properties such as the high surface area to volume ratio, porosity, stability, permeability and morphological similarity to that of extra cellular matrix. Chitosan (CS) has a significant edge over other materials and as a graft material, CS can be used alone or in combination with other materials in the form of nanofibers to provide the structural and biochemical cues for acceleration of bone regeneration. Hence, this review was aimed to provide a detailed study available on CS and its composites prepared as nanofibers, and their associated properties found suitable for bone tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Graphene oxide decorated electrospun gelatin nanofibers: Fabrication, properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Jalaja, K. [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram, Kerala 695 547 (India); Sreehari, V.S. [Indian Institute of Science Education and Research Bhopal, Bhauri, Madhya Pradesh 462066 (India); Kumar, P.R. Anil [Tissue culture laboratory, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Poojappura, Thiruvananthapuram, Kerala 695 012 (India); Nirmala, R. James, E-mail: nirmala@iist.ac.in [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram, Kerala 695 547 (India)

    2016-07-01

    Gelatin nanofiber fabricated by electrospinning process is found to mimic the complex structural and functional properties of natural extracellular matrix for tissue regeneration. In order to improve the physico-chemical and biological properties of the nanofibers, graphene oxide is incorporated in the gelatin to form graphene oxide decorated gelatin nanofibers. The current research effort is focussed on the fabrication and evaluation of physico-chemical and biological properties of graphene oxide-gelatin composite nanofibers. The presence of graphene oxide in the nanofibers was established by transmission electron microscopy (TEM). We report the effect of incorporation of graphene oxide on the mechanical, thermal and biological performance of the gelatin nanofibers. The tensile strength of gelatin nanofibers was increased from 8.29 ± 0.53 MPa to 21 ± 2.03 MPa after the incorporation of GO. In order to improve the water resistance of nanofibers, natural based cross-linking agent, namely, dextran aldehyde was employed. The cross-linked composite nanofibers showed further increase in the tensile strength up to 56.4 ± 2.03 MPa. Graphene oxide incorporated gelatin nanofibers are evaluated for bacterial activity against gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria and cyto compatibility using mouse fibroblast cells (L-929 cells). The results indicate that the graphene oxide incorporated gelatin nanofibers do not prevent bacterial growth, nevertheless support the L-929 cell adhesion and proliferation. - Highlights: • Graphene oxide nano reinforced gelatin nanofibers are fabricated by electrospinning. • Graphene oxide (0.5%) loading resulted in increased tensile strength. • GO/gelatin nanofibers are cross-linked with dextran aldehyde. • Composite nanofibers favoured adhesion of L-929 cells. • GO/gelatin mats do not prevent bacterial growth.

  2. Polypropylene/Polyaniline Nanofiber/Reduced Graphene Oxide Nanocomposite with Enhanced Electrical, Dielectric, and Ferroelectric Properties for a High Energy Density Capacitor.

    Science.gov (United States)

    Cho, Sunghun; Kim, Minkyu; Lee, Jun Seop; Jang, Jyongsik

    2015-10-14

    This work demonstrates a ternary nanocomposite system, composed of polypropylene (PP), redoped PANI (r-PANI) nanofibers, and reduced graphene oxides (RGOs), for use in a high energy density capacitor. r-PANI nanofibers were fabricated by the combination methods of chemical oxidation polymerization and secondary doping processes, resulting in higher conductivity (σ≈156 S cm(-1)) than that of the primarily doped PANI nanofibers (σ≈16 S cm(-1)). RGO sheets with high electron mobility and thermal stability can enhance the conductivity of r-PANI/RGO (σ≈220 S cm(-1)) and thermal stability of PP matrix. These findings could be extended to combine the advantages of r-PANI nanofibers and RGO sheets for developing an efficient means of preparing PP/r-PANI/RGO nanocomposite. When the r-PANI/RGO cofillers (10 vol %) were added to PP matrix, the resulting PP/r-PANI/RGO nanocomposite exhibited high dielectric constant (ε'≈51.8) with small dielectric loss (ε″≈9.3×10(-3)). Furthermore, the PP/r-PANI/RGO nanocomposite was used for an energy-harvesting device, which demonstrated high energy density (Ue≈12.6 J cm(-3)) and breakdown strength (E≈5.86×10(3) kV cm(-1)).

  3. Polyamic Acid Nanofibers Produced by Needleless Electrospinning

    Directory of Open Access Journals (Sweden)

    Oldrich Jirsak

    2010-01-01

    Full Text Available The polyimide precursor (polyamic acid produced of 4,4′-oxydiphthalic anhydride and 4,4′-oxydianiline was electrospun using needleless electrospinning method. Nonwoven layers consisting of submicron fibers with diameters in the range about 143–470 nm on the polypropylene spunbond supporting web were produced. Filtration properties of these nanofiber layers on the highly permeable polypropylene support—namely filtration effectivity and pressure drop—were evaluated. Consequently, these polyamic acid fibers were heated to receive polyimide nanofibers. The imidization process has been studied using IR spectroscopy. Some comparisons with the chemically identical polyimide prepared as the film were made.

  4. Poly(L-lactic acid) nanofibers containing Cissus quadrangularis induced osteogenic differentiation in vitro.

    Science.gov (United States)

    Parvathi, K; Krishnan, Amit G; Anitha, A; Jayakumar, R; Nair, Manitha B

    2018-04-15

    Cissus quadrangularis (CQ) is known as "bone setter" in Ayurvedic Medicine because of its ability to promote fracture healing. Polymers incorporated with CQ at lower concentration have shown to enhance osteogenic differentiation of mesenchymal stem cells (MSCs) in vitro. However, for the healing of clinically relevant critical sized bone defects, large amount of CQ would be required. Based on this perception, a herbal fibrous sheet containing high weight percentage of CQ [20,40 and 60wt/wt% in poly (L-lactic acid) (PLLA)] was fabricated through electrospinning. The solution concentration, flow rate, voltage and tip-target distance was optimized to obtain nanofibers. The hydrophobicity of PLLA fibers was reduced through CQ incorporation. There was considerable increase in the adhesion, proliferation and osteogenic differentiation of MSCs on herbal fibers than normal fibers, mainly on P-Q20 and P-CQ40. MSCs were differentiated into osteoblasts without providing any osteogenic supplements in the medium, indicating its osteoinductive capability. The herbal sheet also could promote mineralization when immersed in simulated body fluid for 14days. These studies specify that PLLA nanofibers loaded with 20 and 40wt% of CQ could serve as a potential candidate for bone tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Modélisation du procédé de soudage hybride Arc / Laser par une approche level set application aux toles d'aciers de fortes épaisseurs A level-set approach for the modelling of hybrid arc/laser welding process application for high thickness steel sheets joining

    Directory of Open Access Journals (Sweden)

    Desmaison Olivier

    2013-11-01

    Full Text Available Le procédé de soudage hybride Arc/Laser est une solution aux assemblages difficiles de tôles de fortes épaisseurs. Ce procédé innovant associe deux sources de chaleur : un arc électrique produit par une torche MIG et une source laser placée en amont. Ce couplage améliore le rendement du procédé, la qualité du cordon et les déformations finales. La modélisation de ce procédé par une approche Level Set permet une prédiction du développement du cordon et du champ de température associé. La simulation du soudage multi-passes d'une nuance d'acier 18MnNiMo5 est présentée ici et les résultats sont comparés aux observations expérimentales. The hybrid arc/laser welding process has been developed in order to overcome the difficulties encountered for joining high thickness steel sheets. This innovative process gathers two heat sources: an arc source developed by a MIG torch and a pre-located laser source. This coupling improves the efficiency of the process, the weld bead quality and the final deformations. The Level-Set approach for the modelling of this process enables the prediction of the weld bead development and the temperature field evolution. The simulation of the multi-passes welding of a 18MnNiMo5 steel grade is detailed and the results are compared to the experimental observations.

  6. Zero percolation threshold in electric conductivity of aluminum nanowire network fabricated by chemical etching using an electrospun nanofiber mask

    Science.gov (United States)

    Azuma, Keisuke; Sakajiri, Koichi; Okabe, Takashi; Matsumoto, Hidetoshi; Kang, Sungmin; Watanabe, Junji; Tokita, Masatoshi

    2017-09-01

    We investigated the sheet resistance (R s) and transmittance (T) of seamless two-dimensional networks of 50-nm-thick aluminum (Al) nanowires (NWs) with widths (W) ranging from 380 to 1410 nm. The Al NWs were fabricated by wet-etching of Al metalized polyester films with using polystyrene (PS) nanofibers as the mask. The PS nanofibers were deposited by the electrospinning of a PS solution and adhered to the film by annealing. W and the area coverage (φ) were increased with increasing PS solution concentration and deposition time, respectively. With increasing φ from 3 to 34%, T and R s decreased from 99 to 75% and from 800 to 10 Ω/sq, respectively, and the network with W = 878 nm at φ = 0.21 attained values of T = 91% and R s = 31 Ω/sq. The conductivity increases with φ with an exponent of 2, demonstrating that seamless NW networks are characterized by the zero percolation threshold.

  7. Hierarchical carbon nanostructure design: ultra-long carbon nanofibers decorated with carbon nanotubes

    International Nuclear Information System (INIS)

    El Mel, A A; Achour, A; Gautron, E; Angleraud, B; Granier, A; Le Brizoual, L; Djouadi, M A; Tessier, P Y; Xu, W; Choi, C H

    2011-01-01

    Hierarchical carbon nanostructures based on ultra-long carbon nanofibers (CNF) decorated with carbon nanotubes (CNT) have been prepared using plasma processes. The nickel/carbon composite nanofibers, used as a support for the growth of CNT, were deposited on nanopatterned silicon substrate by a hybrid plasma process, combining magnetron sputtering and plasma-enhanced chemical vapor deposition (PECVD). Transmission electron microscopy revealed the presence of spherical nanoparticles randomly dispersed within the carbon nanofibers. The nickel nanoparticles have been used as a catalyst to initiate the growth of CNT by PECVD at 600 deg. C. After the growth of CNT onto the ultra-long CNF, SEM imaging revealed the formation of hierarchical carbon nanostructures which consist of CNF sheathed with CNTs. Furthermore, we demonstrate that reducing the growth temperature of CNT to less than 500 deg. C leads to the formation of carbon nanowalls on the CNF instead of CNT. This simple fabrication method allows an easy preparation of hierarchical carbon nanostructures over a large surface area, as well as a simple manipulation of such material in order to integrate it into nanodevices.

  8. Diverse Supramolecular Nanofiber Networks Assembled by Functional Low-Complexity Domains.

    Science.gov (United States)

    An, Bolin; Wang, Xinyu; Cui, Mengkui; Gui, Xinrui; Mao, Xiuhai; Liu, Yan; Li, Ke; Chu, Cenfeng; Pu, Jiahua; Ren, Susu; Wang, Yanyi; Zhong, Guisheng; Lu, Timothy K; Liu, Cong; Zhong, Chao

    2017-07-25

    Self-assembling supramolecular nanofibers, common in the natural world, are of fundamental interest and technical importance to both nanotechnology and materials science. Despite important advances, synthetic nanofibers still lack the structural and functional diversity of biological molecules, and the controlled assembly of one type of molecule into a variety of fibrous structures with wide-ranging functional attributes remains challenging. Here, we harness the low-complexity (LC) sequence domain of fused in sarcoma (FUS) protein, an essential cellular nuclear protein with slow kinetics of amyloid fiber assembly, to construct random copolymer-like, multiblock, and self-sorted supramolecular fibrous networks with distinct structural features and fluorescent functionalities. We demonstrate the utilities of these networks in the templated, spatially controlled assembly of ligand-decorated gold nanoparticles, quantum dots, nanorods, DNA origami, and hybrid structures. Owing to the distinguishable nanoarchitectures of these nanofibers, this assembly is structure-dependent. By coupling a modular genetic strategy with kinetically controlled complex supramolecular self-assembly, we demonstrate that a single type of protein molecule can be used to engineer diverse one-dimensional supramolecular nanostructures with distinct functionalities.

  9. UV-responsive polyvinyl alcohol nanofibers prepared by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Khatri, Zeeshan, E-mail: zeeshan.khatri@faculty.muet.edu.pk [Department of Textile Engineering, Mehran University of Engineering and Technology, Jamshoro 76062 (Pakistan); Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan); Ali, Shamshad [Department of Textile Engineering, Mehran University of Engineering and Technology, Jamshoro 76062 (Pakistan); Department of Organic and Nano Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Khatri, Imran [Department of Entomology, Sindh Agriculture University, Tandojam (Pakistan); Mayakrishnan, Gopiraman [Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan); Kim, Seong Hun [Department of Organic and Nano Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Ick-Soo, E-mail: kim@shinshu-u.ac.jp [Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan)

    2015-07-01

    Graphical abstract: - Highlights: • UV responsive PVA nanofibers were prepared via electrospinning. • Quick response codes were recorded multiple times on UV responsive nanofibers. • The rate of photo-coloration was found faster than the rate of photo-reversibility. - Abstract: We report UV-responsive polyvinyl alcohol (PVA) nanofibers for potential application for recording and erasing quick response (QR) codes. We incorporate 1′-3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2′-(2H)-indole] (indole) and,3-dihydro-1,3,3-trimethylspiro [2H-indole-2,3′-[3H] phenanthr [9,10-b] (1,4) oxazine] (oxazine) into PVA polymer matrix via electrospinning technique. The resultant nanofibers were measured for recording–erasing, photo-coloration and thermal reversibility. The rate of photo-coloration of PVA–indole nanofibers was five times higher than the PVA–oxazine nanofibers, whereas the thermal reversibility found to be more than twice as fast as PVA–oxazine nanofibers. Results showed that the resultant nanofibers have very good capability of recording QR codes multiple times. The FTIR spectroscopy and SEM were employed to characterize the electrospun nanofibers. The UV-responsive PVA nanofibers have great potentials as a light-driven nanomaterials incorporated within sensors, sensitive displays and in optical devices such as erasable and rewritable optical storage.

  10. UV-responsive polyvinyl alcohol nanofibers prepared by electrospinning

    International Nuclear Information System (INIS)

    Khatri, Zeeshan; Ali, Shamshad; Khatri, Imran; Mayakrishnan, Gopiraman; Kim, Seong Hun; Kim, Ick-Soo

    2015-01-01

    Graphical abstract: - Highlights: • UV responsive PVA nanofibers were prepared via electrospinning. • Quick response codes were recorded multiple times on UV responsive nanofibers. • The rate of photo-coloration was found faster than the rate of photo-reversibility. - Abstract: We report UV-responsive polyvinyl alcohol (PVA) nanofibers for potential application for recording and erasing quick response (QR) codes. We incorporate 1′-3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2′-(2H)-indole] (indole) and,3-dihydro-1,3,3-trimethylspiro [2H-indole-2,3′-[3H] phenanthr [9,10-b] (1,4) oxazine] (oxazine) into PVA polymer matrix via electrospinning technique. The resultant nanofibers were measured for recording–erasing, photo-coloration and thermal reversibility. The rate of photo-coloration of PVA–indole nanofibers was five times higher than the PVA–oxazine nanofibers, whereas the thermal reversibility found to be more than twice as fast as PVA–oxazine nanofibers. Results showed that the resultant nanofibers have very good capability of recording QR codes multiple times. The FTIR spectroscopy and SEM were employed to characterize the electrospun nanofibers. The UV-responsive PVA nanofibers have great potentials as a light-driven nanomaterials incorporated within sensors, sensitive displays and in optical devices such as erasable and rewritable optical storage

  11. Enhanced Electrochemical Performance of Electrospun Ag/Hollow Glassy Carbon Nanofibers as Free-standing Li-ion Battery Anode

    International Nuclear Information System (INIS)

    Shilpa; Sharma, Ashutosh

    2015-01-01

    Silver with a high theoretical capacity for lithium storage is an attractive alloy based anode for Li-ion batteries, but large volume changes associated with AgLi x alloy formation leads to electrode cracking, pulverization and rapid capacity fading. A buffer matrix, like the electrospun hollow carbon nanofibers, can reduce this problem to a great extent. Herein, we demonstrate the facile synthesis of a free-standing, binder free Ag-C hybrid electrode through co-axial electrospinning, where well dispersed Ag nanoparticles are embedded in hollow carbon nanofibers. Using this approach, the long cycle life of carbon is complemented with the high lithium storage capacity of Ag, resulting in a high performance anode. The Ag-C composite electrode delivers a capacity of 739 mAh g −1 (>conventional graphite anodes) at 50 mA g −1 , with ∼85% capacity retention after 100 cycles. In addition, the Ag-C composite nanofibers are highly porous and exhibit a large accessible surface area (∼726.9 m 2 g −1 ) with an average pore diameter of ∼6.07 nm. The encapsulation of Ag in the hollow interiors not only provides additional lithium storage sites but also enhances the electronic conductivity, which combined with the reduced lithium diffusion path lengths in the nanofibers result in faster charge-discharge kinetics and hence a high rate performance

  12. Designer bFGF-incorporated D-form self-assembly peptide nanofiber scaffolds to promote bone repair

    Energy Technology Data Exchange (ETDEWEB)

    He, Bin, E-mail: binheing@163.com [Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Ou, Yunsheng; Chen, Shuo; Zhao, Weikang; Zhou, Ao [Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Zhao, Jinqiu [Department of Infectious Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Li, Hong [School of Physical Science and Technology, Sichuan University, Chengdu 610000 (China); Jiang, Dianming [Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Zhu, Yong, E-mail: 568731668@qq.com [Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China)

    2017-05-01

    D-Form and L-form peptide nanofiber scaffolds can spontaneously form stable β-sheet secondary structures and nanofiber hydrogel scaffolds, and hold some promise in hemostasis and wound healing. We report here on the synthetic self-assembling peptide D-RADA16 and L-RADA16 are both found to produce stable β-sheet secondary structure and nanofiber hydrogel scaffolds based on circular dichroism (CD) spectroscopy, transmission electron microscopy (TEM) and rheology analysis etc. D-RADA16 hydrogel and L-RADA16 hydrogel can enhance obvious bone repair in femoral condyle defects of the Sprague-Dawley (SD) rat model compared to PBS treatment. Based on micro-computed tomography (CT), it was revealed that D-RADA16 hydrogel and L-RADA16 hydrogel were capable to obtain the extensive bone healing. Histological evaluation also found that these two hydrogels facilitate the presence of more mature bone tissue within the femoral condyle defects. Additionally, D-RADA16 hydrogel showed some potential in storing and releasing basic-fibroblast growth factor (bFGF) which was able to further promote bone regeneration based on micro-CT analysis. These results indicate that D-form peptide nanofiber hydrogel have some special capacity for bone repair. - Highlights: • Peptide D-RADA16 and L-RADA16 can form stable hydrogels. • D-RADA16 hydrogel can obtain the comparable and extensive promotion to bone healing compared to L-RADA16 hydrogel. • L-RADA16 hydrogel allows for slow release of bFGF.

  13. Preparation of nitrogen-doped biomass-derived carbon nanofibers/graphene aerogel as a binder-free electrode for high performance supercapacitors

    Science.gov (United States)

    Zhang, Yimei; Wang, Fei; Zhu, Hao; Zhou, Lincheng; Zheng, Xinliang; Li, Xinghua; Chen, Zhuang; Wang, Yue; Zhang, Dandan; Pan, Duo

    2017-12-01

    Carbon materials derived from various biomasses have aroused forceful interest from scientific community based on their abundant resource, low cost, environment friendly and easy fabrication. Herein, the method has been developed to prepare nitrogen-doped biomass-derived carbon nanofibers/graphene aerogel (NCGA) as the binder-free electrode for supercapacitors. Ethylenediamine (EDA) is select as nitrogen source for its high nitrogen content and strong interaction with graphene oxide (GO) and cellulose nanofibers (CNFs) via hydrothermal self-assembly method to form hybrid hydrogel, and finally converts to NCGA by freeze-drying and carbonization. After carbonization the insulated CNFs converted to high conductivity carbon nanofibers. The NCGA electrode exhibits a high specific capacitance of 289 F g-1 at 5 mV s-1 and high stability of 90.5% capacitance retention ratio after 5000 cycles at 3 A g-1. This novel biomass electrode could be potential candidate for high performance supercapacitors.

  14. Electrospun nanofibers for energy and environmental applications

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Bin; Yu, Jianyong (eds.) [Donghua Univ., Shanghai (China). State Key Lab. for Modification of Chemical Fibers and Polymer Materials; Donghua Univ., Shanghai (China). Nanomaterials Research Center

    2014-10-01

    This book offers a comprehensive review of the latest advances in developing functional electrospun nanofibers for energy and environmental applications, which include fuel cells, lithium-ion batteries, solar cells, supercapacitors, energy storage materials, sensors, filtration materials, protective clothing, catalysis, structurally-colored fibers, oil spill cleanup, self-cleaning materials, adsorbents, and electromagnetic shielding.

  15. PRODUKSI NANOFIBER DAN APLIKASINYA DALAM PENGOLAHAN AIR

    OpenAIRE

    Krisnandika, Vania Elita

    2017-01-01

    Abstrak Kebutuhan air meningkat seiring meningkatnya jumlah penduduk dan taraf kehidupan masyarakat. Pembangunan yang dilakukan secara terus-menerus dan sangat cepat di Indonesia mengakibatkan penurunan kualitas air permukaan. Teknologi membran merupakan salah satu teknologi pengolahan air yang menghasilkan produk dengan kualitas tinggi. Membran berstruktur nano, khususnya nanofiber, saat ini menjadi perhatian karena menjawab kebutuhan teknologi filtrasi yang efektif dan hemat biaya. Pr...

  16. Fluorescent Self-Assembled Polyphenylene Dendrimer Nanofibers

    NARCIS (Netherlands)

    Liu, Daojun; Feyter, Steven De; Cotlet, Mircea; Wiesler, Uwe-Martin; Weil, Tanja; Herrmann, Andreas; Müllen, Klaus; Schryver, Frans C. De

    2003-01-01

    A second-generation polyphenylene dendrimer 1 self-assembles into nanofibers on various substrates such as HOPG, silicon, glass, and mica from different solvents. The investigation with noncontact atomic force microscopy (NCAFM) and scanning electron microscopy (SEM) shows that the morphology of the

  17. Photosensitive semiconducting polymer-incorporated nanofibers for promoting the regeneration of skin wound

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Guorui [Institute of Materials Research and Engineering, A*STAR, 2 Fusionopolis Way, Innovis, #08-03, 138634 (Singapore); The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Xi' an Jiaotong University, School of Life Science and Technology, Xi' an 710049 (China); Li, Jun [Institute of Materials Research and Engineering, A*STAR, 2 Fusionopolis Way, Innovis, #08-03, 138634 (Singapore); Department of Chemistry and Centre for Plastic Electronics, Imperial College London, London SW7 2AZ (United Kingdom); Li, Kai, E-mail: kai_li_cn@hotmail.com [Institute of Materials Research and Engineering, A*STAR, 2 Fusionopolis Way, Innovis, #08-03, 138634 (Singapore); Department of Radiology and Molecular Imaging Program at Stanford (MIPS), Stanford School of Medicine, Stanford, 94305 (United States)

    2017-01-01

    Photosensitive semiconducting polymer (SP) combined with light stimulation has shown the capability in promoting the proliferation of human dermal fibroblasts (HDFs). However, the high cytotoxicity of the used SP hindered its further application in bioactive scaffolds. In this contribution, we designed and synthesized a SP, poly (N,N-bis(2-octyldodecyl)-3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c] pyrrole-1,4-dione-alt-thieno[3,2-b]thiophene) (PDBTT) with low cytotoxicity and strong absorbance in red and near-infrared region (600–1200 nm). The photosensitive SP was then applied in electrospun poly(ε-caprolactone) (PCL) nanofibrous scaffold and evaluated its proliferative effect on HDFs under the illumination from red light-emitting diode (LED) with high tissue penetration. After 9 days of continuous stimulation, the hybrid electrospun PCL/PDBTT nanofibers with low cytotoxicity showed excellent support for HDFs adhesion, proliferation and collagen secretion than neat PCL nanofibers and HDFs on the stimulated PCL/PDBTT nanofibers gained typical spindle morphology, indicating the well cell spreading on the stimulated PCL/PDBTT nanofibers. The incorporation of functional materials within synthetic biomaterials could be a novel way in improving the performance of engineered tissue constructs by providing multiple cues (e.g. electrical stimulation) to the attached cells. - Highlights: • A photosensitive semiconducting polymer (SP) was applied in electrospun nanofibrous scaffold. • The SP-incorporated scaffold could promote cell proliferation upon light stimulation. • The designed photosensitive SP could be applied as functional material with low cost and high durability in skin tissue engineering.

  18. Synthesis and Characterization of Polyaniline/Graphene Composite Nanofiber and Its Application as an Electrochemical DNA Biosensor for the Detection of Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Fatimah Syahidah Mohamad

    2017-12-01

    Full Text Available This article describes chemically modified polyaniline and graphene (PANI/GP composite nanofibers prepared by self-assembly process using oxidative polymerization of aniline monomer and graphene in the presence of a solution containing poly(methyl vinyl ether-alt-maleic acid (PMVEA. Characterization of the composite nanofibers was carried out by Fourier transform infrared (FTIR and Raman spectroscopy, transmission electron microscopy (TEM and scanning electron microscopy (SEM. SEM images revealed the size of the PANI nanofibers ranged from 90 to 360 nm in diameter and was greatly influenced by the proportion of PMVEA and graphene. The composite nanofibers with an immobilized DNA probe were used for the detection of Mycobacterium tuberculosis by using an electrochemical technique. A photochemical indicator, methylene blue (MB was used to monitor the hybridization of target DNA by using differential pulse voltammetry (DPV method. The detection range of DNA biosensor was obtained from of 10−6–10−9 M with the detection limit of 7.853 × 10−7 M under optimum conditions. The results show that the composite nanofibers have a great potential in a range of applications for DNA sensors.

  19. Development and characterization of highly oriented PAN nanofiber

    Directory of Open Access Journals (Sweden)

    M. Sadrjahani

    2010-12-01

    Full Text Available A simple and non-conventional electrospinning technique was employed for producing highly oriented Polyacrylonitrile (PAN nanofibers. The PAN nanofibers were electrospun from 14 wt% solution of PAN in dimethylformamid (DMF at 11 kv on a rotating drum with various linear speeds from 22.5 m/min to 67.7 m/min. The influence of take up velocity was investigated on the degree of alignment, internal structure and mechanical properties of collected PAN nanofibers. Using an image processing technique, the best degree of alignment was obtained for those nanofibers collected at a take up velocity of 59.5 m/min. Moreover, Raman spectroscopy was used for measuring molecular orientation of PAN nanofibers. Similarly, a maximum chain orientation parameter of 0.25 was determined for nanofibers collected at a take up velocity of 59.5 m/min.

  20. Preparation and Properties of Flexible AZO@C Nanofibers

    Directory of Open Access Journals (Sweden)

    MA Hui

    2018-01-01

    Full Text Available A new type of environmental-friendly flexible nanofibers of aluminum doped zinc oxide (AZO coated carbon (AZO@C was successfully prepared by using polyvinyl alcohol (PVA as raw materials. The as-spun PVA nanofibers were prepared via electrospinning and its water resistance was greatly improved after heat-treatment. Then, the PVA nanofibers with a layer of zinc aluminum hydroxide on the surface were synthesized by hydrothermal method. Thereafter, new AZO@C composite nanofibers was produced after sintering at 500℃ to the carbonization of PVA nanofibers and the dehydration of zinc aluminum hydroxide to form AZO nanoparticles. The structure and properties of the samples were characterized by Fourier-transform infrared spectrometer (FT-IR, thermal gravimetric analyzer (TGA and scanning electron microscope (SEM. The average diameter of the AZO@C nanofibers is (320±45nm. The photocatalytic property of the resultant composite fibers is demonstrated by degrading methyl orange under solar light.

  1. Biscrolling nanotube sheets and functional guests into yarns

    Science.gov (United States)

    Baughman, Ray

    2011-03-01

    Multifunctional applications of textiles have been limited by the inability to spin important materials into yarns. Generically applicable methods are demonstrated for producing weavable yarns comprising up to 95 wt % of otherwise unspinnable particulate or nanofiber powders that remain highly functional. Scrolled 50 nm thick carbon nanotube sheets confine these powders in the galleries of irregular scroll sacks, whose observed complex structures are related to twist-dependent extension of Archimedean spirals, Fermat spirals, or spiral pairs into scrolls. The strength and electronic connectivity of a small weight fraction of scrolled carbon nanotube sheet enables yarn weaving, sewing, knotting, braiding, and charge collection. This technology is used to make yarns of superconductors, Li-ion battery materials, graphene ribbons, catalytic nanofibers for fuel cells, and Ti O2 for photocatalysis. Work done in collaboration with Shaoli Fang, Xavier Lepro-Chavez, Chihye Lewis, Raquel Ovalle-Robles, Javier Carratero-Gonzalez, Elisabet Castillo-Martinez, Mikhail Kozlov, Jiyoung Oh, Neema Rawat, Carter Haines, Mohammed Haque, Vaishnavi Aare, Stephanie Stoughton, Anvar Zakhidov, and Ray Baughman, The University of Texas at Dallas / Alan G. MacDiarmid NanoTech Institute.

  2. Regeneration of Bombyx mori silk nanofibers and nanocomposite fibrils by the electrospinning process

    Science.gov (United States)

    Ayutsede, Jonathan Eyitouyo

    In recent years, there has been significant interest in the utilization of natural materials for novel nanoproducts such as tissue engineered scaffolds. Silkworm silk fibers represent one of the strongest natural fibers known. Silkworm silk, a protein-based natural biopolymer, has received renewed interest in recent years due to its unique properties (strength, toughness) and potential applications such as smart textiles, protective clothing and tissue engineering. The traditional 10--20 mum diameter, triangular-shaped Bombyx mori fibers have remained unchanged over the years. However, in our study, we examine the scientific implication and potential applications of reducing the diameter to the nanoscale, changing the triangular shape of the fiber and adding nanofillers in the form of single wall carbon nanotubes (SWNT) by the electrospinning process. The electrospinning process preserves the natural conformation of the silk (random and beta-sheet). The feasibility of changing the properties of the electrospun nanofibers by post processing treatments (annealing and chemical treatment) was investigated. B. mori silk fibroin solution (formic acid) was successfully electrospun to produce uniform nanofibers (as small as 12 nm). Response Surface Methodology (RSM) was applied for the first time to experimental results of electrospinning, to develop a processing window that can reproduce regenerated silk nanofibers of a predictable size (d silk multifunctional nanocomposite fibers were fabricated for the first time with anticipated properties (mechanical, thermal and electrically conductive) that may have scientific applications (nerve regeneration, stimulation of cell-scaffold interaction). In order to realize these applications, the following areas need to be addressed: a systematic investigation of the dispersion of the nanotubes in the silk matrix, a determination of new methodologies for characterizing the nanofiber properties and establishing the nature of the silk

  3. Nanofiber Nerve Guide for Peripheral Nerve Repair and Regeneration

    Science.gov (United States)

    2016-04-01

    1 Award Number: W81XWH-11-2-0047 TITLE: Nanofiber Nerve Guide for Peripheral Nerve Repair and Regeneration PRINCIPAL INVESTIGATOR: Ahmet Höke...TITLE AND SUBTITLE 5a. CONTRACT NUMBER W81XWH-11-2-0047 Nanofiber nerve guide for peripheral nerve repair and regeneration 5b. GRANT NUMBER...goal of this collaborative research project was to develop next generation engineered nerve guide conduits (NGCs) with aligned nanofibers and

  4. Modeling Temperature Dependent Singlet Exciton Dynamics in Multilayered Organic Nanofibers

    DEFF Research Database (Denmark)

    de Sousa, Leonardo Evaristo; de Oliveira Neto, Pedro Henrique; Kjelstrup-Hansen, Jakob

    2018-01-01

    Organic nanofibers have shown potential for application in optoelectronic devices because of the tunability of their optical properties. These properties are influenced by the electronic structure of the molecules that compose the nanofibers, but also by the behavior of the excitons generated...... dynamics in multilayered organic nanofibers. By simulating absorption and emission spectra, the possible Förster transitions are identified. Then, a Kinetic Monte Carlo (KMC) model is employed in combination with a genetic algorithm to theoretically reproduce time resolved photoluminescence measurements...

  5. Improved photocatalytic degradation of Orange G using hybrid nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Ledwaba, Mpho; Masilela, Nkosiphile; Nyokong, Tebello; Antunes, Edith, E-mail: ebeukes@uwc.ac.za [Rhodes University, Department of Chemistry (South Africa)

    2017-05-15

    Functionalised electrospun polyamide-6 (PA-6) nanofibres incorporating gadolinium oxide nanoparticles conjugated to zinc tetracarboxyphenoxy phthalocyanine (ZnTCPPc) as the sensitizer were prepared for the photocatalytic degradation of Orange G. Fibres incorporating the phthalocyanine alone or a mixture of the nanoparticles and phthalocyanine were also generated. The singlet oxygen-generating ability of the sensitizer was shown to be maintained within the fibre mat, with the singlet oxygen quantum yields increasing upon incorporation of the magnetic nanoparticles. Consequently, the rate of the photodegradation of Orange G was observed to increase with an increase in singlet oxygen quantum yield. A reduction in the half-lives for the functionalised nanofibres was recorded in the presence of the magnetic nanoparticles, indicating an improvement in the efficiency of the degradation process.

  6. High Performance Artificial Muscles Using Nanofiber and Hybrid Yarns

    Science.gov (United States)

    2015-07-14

    2. Above advance led to “Artificial Muscles From Fishing Line and Sewing Thread”, which was patent filed and then published in Science in 2014...consuming significant energy. The publication of Artificial Muscles From Fishing Line and Sewing Thread (Science, 2014) generated TV, radio, and other...gn f cant energy. The pub cat on of “Art f c a Musc es From F sh ng L ne and Sew ng Thread” (Sc ence, 2014) generated TV, rad o, and other wor d-w de

  7. Guiding the orientation of smooth muscle cells on random and aligned polyurethane/collagen nanofibers.

    Science.gov (United States)

    Jia, Lin; Prabhakaran, Molamma P; Qin, Xiaohong; Ramakrishna, Seeram

    2014-09-01

    Fabricating scaffolds that can simulate the architecture and functionality of native extracellular matrix is a huge challenge in vascular tissue engineering. Various kinds of materials are engineered via nano-technological approaches to meet the current challenges in vascular tissue regeneration. During this study, nanofibers from pure polyurethane and hybrid polyurethane/collagen in two different morphologies (random and aligned) and in three different ratios of polyurethane:collagen (75:25; 50:50; 25:75) are fabricated by electrospinning. The fiber diameters of the nanofibrous scaffolds are in the range of 174-453 nm and 145-419 for random and aligned fibers, respectively, where they closely mimic the nanoscale dimensions of native extracellular matrix. The aligned polyurethane/collagen nanofibers expressed anisotropic wettability with mechanical properties which is suitable for regeneration of the artery. After 12 days of human aortic smooth muscle cells culture on different scaffolds, the proliferation of smooth muscle cells on hybrid polyurethane/collagen (3:1) nanofibers was 173% and 212% higher than on pure polyurethane scaffolds for random and aligned scaffolds, respectively. The results of cell morphology and protein staining showed that the aligned polyurethane/collagen (3:1) scaffold promote smooth muscle cells alignment through contact guidance, while the random polyurethane/collagen (3:1) also guided cell orientation most probably due to the inherent biochemical composition. Our studies demonstrate the potential of aligned and random polyurethane/collagen (3:1) as promising substrates for vascular tissue regeneration. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  8. Facile Preparation and Enhanced Capacitance of the Ag-PEDOT:PSS/Polyaniline Nanofiber Network for Supercapacitors

    International Nuclear Information System (INIS)

    Patil, Dipali S.; Pawar, Sachin A.; Kim, Jin Hyeok; Patil, Pramod S.; Shin, Jae Cheol

    2016-01-01

    Graphical abstract: Fig. shows the steps involved in the development of the AgNW-PEDOT:PSS/PANI electrode. The bright silver nanocubes were observed onto the PANI nanofibers. This means that during the electrodeposition of PANI, there is an electrostatic interaction between AgNWs and PANI; the AgNWs are segmented into the small nanocubes. These nanocubes are distributed equally all over the interconnected network of the PANI nanofibers. This provides a continuous path for the electrons during the charge/discharge process. - Highlights: • Ag-PEDOT:PSS/PANI hybrid nanostructure was prepared. • Dip coating and electrodeposition techniques are used for electrodes preparation. • Symmetric supercapacitor based on AgNW-PEDOT:PSS/PANI was developed. • The positive synergistic effect of AgNW, PEDOT:PSS and PANI was observed. - Abstract: This paper reports the synthesis of a silver − Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/Polyaniline(Ag-PEDOT:PSS/PANI)hybrid nanostructure using a simple dip coating technique followed by potentiodynamic electrodeposition to achieve an electrochemical supercapacitor with excellent electrochemical performance. In this sandwich type structure, the Ag nanostructure-blended PEDOT: PSS acts as a current collector, where electrons can be transferred easily through this network to the PANI nanofibers and vice versa. The AgNW-PEDOT:PSS/PANI showed a specific capacitance of 643 Fg −1 at 10 mVs −1 and an energy density of 86.19 Whkg −1 at 0.1 mA, indicating the positive synergistic effect of silver nanowires (AgNW), PEDOT:PSS and PANI. The Ag nanostructure incorporated PEDOT:PSS helps to improve the electronic conductivity and the electrochemical stability of the PANI electrodes. Promising electrochemical properties achieved from the measurement of symmetric device demonstrate the ideal capacitive behavior of our prepared electrodes.

  9. Carbon nanofibers: a versatile catalytic support

    Directory of Open Access Journals (Sweden)

    Nelize Maria de Almeida Coelho

    2008-09-01

    Full Text Available The aim of this article is present an overview of the promising results obtained while using carbon nanofibers based composites as catalyst support for different practical applications: hydrazine decomposition, styrene synthesis, direct oxidation of H2S into elementary sulfur and as fuel-cell electrodes. We have also discussed some prospects of the use of these new materials in total combustion of methane and in ammonia decomposition. The macroscopic carbon nanofibers based composites were prepared by the CVD method (Carbon Vapor Deposition employing a gaseous mixture of hydrogen and ethane. The results showed a high catalytic activity and selectivity in comparison to the traditional catalysts employed in these reactions. The fact was attributed, mainly, to the morphology and the high external surface of the catalyst support.

  10. General strategy for fabricating thoroughly mesoporous nanofibers

    KAUST Repository

    Hou, Huilin

    2014-12-03

    Recently, preparation of mesoporous fibers has attracted extensive attentions because of their unique and broad applications in photocatalysis, optoelectronics, and biomaterials. However, it remains a great challenge to fabricate thoroughly mesoporous nanofibers with high purity and uniformity. Here, we report a general, simple and cost-effective strategy, namely, foaming-assisted electrospinning, for producing mesoporous nanofibers with high purity and enhanced specific surface areas. As a proof of concept, the as-fabricated mesoporous TiO2 fibers exhibit much higher photocatalytic activity and stability than both the conventional solid counterparts and the commercially available P25. The abundant vapors released from the introduced foaming agents are responsible for the creation of pores with uniform spatial distribution in the spun precursor fibers. The present work represents a critically important step in advancing the electrospinning technique for generating mesoporous fibers in a facile and universal manner.

  11. Antibacterial nanofiber materials activated by light

    Czech Academy of Sciences Publication Activity Database

    Jesenská, S.; Plištil, L.; Kubát, Pavel; Lang, Kamil; Brožová, Libuše; Popelka, Štěpán; Szatmáry, Lórant; Mosinger, Jiří

    99A, č. 4 (2011), s. 676-683 ISSN 1549-3296 R&D Projects: GA ČR GAP208/10/1678 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40320502; CEZ:AV0Z40500505 Keywords : antibacterial nanofiber materials * photoactive * singlet oxygen Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.625, year: 2011

  12. High thermoelectric performance of graphite nanofibers

    OpenAIRE

    Tran, Van-Truong; Saint-Martin, Jérôme; Dollfus, Philippe; Volz, Sebastian

    2017-01-01

    Graphite nanofibers (GNFs) have been demonstrated to be a promising material for hydrogen storage and heat management in electronic devices. Here, by means of first-principles and transport simulations, we show that GNFs can also be an excellent material for thermoelectric applications thanks to the interlayer weak van der Waals interaction that induces low thermal conductance and a step-like shape in the electronic transmission with mini-gaps, which are necessary ingredients to achieve high ...

  13. Silica decorated on porous activated carbon nanofiber composites for high-performance supercapacitors

    Science.gov (United States)

    Kim, So Yeun; Kim, Bo-Hye

    2016-10-01

    A hybrid of silica decorated on porous activated carbon nanofibers (ACNFs) is fabricated in the form of a web via electrospinning and an activation process as an electrode material for electrochemical capacitors in an organic electrolyte. The introduction of PhSiH3 (PS) into the polyacrylonitrile (PAN) solution induces a porous ACNF structure containing silica nanoparticles (NPs) via the spontaneous sol-gel process of PS by steam in the subsequent physical activation process. These inorganic-organic hybrid composites of porous ACNF containing silica NPs show superior specific capacitance and energy density in electrochemical tests, along with good rate capability and excellent cycle life in an organic electrolyte, which is attributed to the combination of ACNF's high surface area and silica's hydrophilicity. The electrochemical performance decreases with increasing PS concentration, and this trend is consistent with the specific surface area results, which reveal the rapid formation of a double layer.

  14. Perspectives: Nanofibers and nanowires for disordered photonics

    Directory of Open Access Journals (Sweden)

    Dario Pisignano

    2017-03-01

    Full Text Available As building blocks of microscopically non-homogeneous materials, semiconductor nanowires and polymer nanofibers are emerging component materials for disordered photonics, with unique properties of light emission and scattering. Effects found in assemblies of nanowires and nanofibers include broadband reflection, significant localization of light, strong and collective multiple scattering, enhanced absorption of incident photons, synergistic effects with plasmonic particles, and random lasing. We highlight recent related discoveries, with a focus on material aspects. The control of spatial correlations in complex assemblies during deposition, the coupling of modes with efficient transmission channels provided by nanofiber waveguides, and the embedment of random architectures into individually coded nanowires will allow the potential of these photonic materials to be fully exploited, unconventional physics to be highlighted, and next-generation optical devices to be achieved. The prospects opened by this technology include enhanced random lasing and mode-locking, multi-directionally guided coupling to sensors and receivers, and low-cost encrypting miniatures for encoders and labels.

  15. Investigation of electrochemical actuation by polyaniline nanofibers

    Science.gov (United States)

    Mehraeen, Shayan; Alkan Gürsel, Selmiye; Papila, Melih; Çakmak Cebeci, Fevzi

    2017-09-01

    Polyaniline nanofibers have shown promising electrical and electrochemical properties which make them prominent candidates in the development of smart systems employing sensors and actuators. Their electrochemical actuation potential is demonstrated in this study. A trilayer composite actuator based on polyaniline nanofibers was designed and fabricated. Cross-linked polyvinyl alcohol was sandwiched between two polyaniline nanofibrous electrodes as ion-containing electrolyte gel. First, electrochemical behavior of a single electrode was studied, showing reversible redox peak pairs in 1 M HCl using a cyclic voltammetry technique. High aspect ratio polyaniline nanofibers create a porous network which facilitates ion diffusion and thus accelerates redox reactions. Bending displacement of the prepared trilayer actuator was then tested and reported under an AC potential stimulation as low as 0.5 V in a variety of frequencies from 50 to 1000 mHz, both inside 1 M HCl solution and in air. Decay of performance of the composite actuator in air is investigated and it is reported that tip displacement in a solution was stable and repeatable for 1000 s in all selected frequencies.

  16. Chitosan nanofibers for transbuccal insulin delivery.

    Science.gov (United States)

    Lancina, Michael G; Shankar, Roopa Kanakatti; Yang, Hu

    2017-05-01

    In this work, they aimed at producing chitosan based nanofiber mats capable of delivering insulin via the buccal mucosa. Chitosan was electrospun into nanofibers using poly(ethylene oxide) (PEO) as a carrier molecule in various feed ratios. The mechanical properties and degradation kinetics of the fibers were measured. Insulin release rates were determined in vitro using an ELISA assay. The bioactivity of released insulin was measured in terms of Akt activation in pre-adipocytes. Insulin permeation across the buccal mucosa was measured in an ex-vivo porcine transbuccal model. Fiber morphology, mechanical properties, and in vitro stability were dependent on PEO feed ratio. Lower PEO content blends produced smaller diameter fibers with significantly faster insulin release kinetics. Insulin showed no reduction in bioactivity due to electrospinning. Buccal permeation of insulin facilitated by high chitosan content blends was significantly higher than that of free insulin. Taken together, the work demonstrates that chitosan-based nanofibers have the potential to serve as a transbuccal insulin delivery vehicle. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1252-1259, 2017. © 2017 Wiley Periodicals, Inc.

  17. Fabrication of NiO/zirconium oxide nanofibers by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Sundarrajan, Subramanian, E-mail: sundarnus1@gmail.com [Department of Mechanical Engineering, NUS, 117576 (Singapore); Venkatesan, Arunachalam; Agarwal, Satya R.; Shaik Anwar Ahamed, Nabeela Nasreen [Department of Mechanical Engineering, NUS, 117576 (Singapore); Ramakrishna, Seeram, E-mail: seeram@nus.edu.sg [Department of Mechanical Engineering, NUS, 117576 (Singapore); King Saud University, Riyadh 11451 (Saudi Arabia); Institute of Materials Research and Engineering, 117602 (Singapore)

    2014-12-01

    The electrospinning technique has been used to fabricate 1D inorganic–organic composite nanofibers from solutions containing poly(vinyl alcohol) (PVA) and suitable aqueous precursors of nickel and zirconium ions. Upon calcination, nickel oxide/zirconia nanofibers retained the original morphological features of as-spun nanofibers. X-ray diffraction was used to identify the crystalline nature of the final product and analytical tools such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM) were employed to elucidate the pathway of ceramic phase formation and the systematic evolution of morphological features in the as-spun and calcined fibers. These fibers will find potential applications in biomedical field. - Highlights: • PVA/NiO/zirconia composite nanofibers were synthesized via electrospinning. • Green processing of nanofibers using only water as solvent. • Calcination of composite nanofibers to yield ceramic nanofibers. • High aspect ratio nanofibers with diameters 106 ± 25 nm • The application of these fibers as dental composites and bone tissue engineering.

  18. Fabrication of Cationic Exchange Polystyrene Nanofibers for Drug ...

    African Journals Online (AJOL)

    Purpose: To prepare polystyrene nanofiber ion exchangers (PSNIE) with surface cation exchange functionality using a new method based on electrospinning and also to optimize crosslinking and sulfonation reactions to obtain PSNIE with maximum ion exchange capacity (IEC). Method: The nanofibers were prepared from ...

  19. High performance co-polyimide nanofiber reinforced composites

    NARCIS (Netherlands)

    Yao, Jian; Li, Guang; Bastiaansen, Cees; Peijs, Ton

    2015-01-01

    Electrospun co-polyimide BPDA (3, 3′, 4, 4′-Biphenyltetracarboxylic dianhydride)/PDA (p-Phenylenediamine)/ODA (4, 4′-oxydianiline) nanofiber reinforced flexible composites were manufactured by impregnating these high performance nanofibers with styrene-butadiene-styrene (SBS) triblock copolymer

  20. Beyond Slurry-Cast Supercapacitor Electrodes: PAN/MWNT Heteromat-Mediated Ultrahigh Capacitance Electrode Sheets

    Science.gov (United States)

    Lee, Jung Han; Kim, Jeong A.; Kim, Ju-Myung; Lee, Sun-Young; Yeon, Sun-Hwa; Lee, Sang-Young

    2017-01-01

    Supercapacitors (SCs) have garnered considerable attention as an appealing power source for forthcoming smart energy era. An ultimate challenge facing the SCs is the acquisition of higher energy density without impairing their other electrochemical properties. Herein, we demonstrate a new class of polyacrylonitrile (PAN)/multi-walled carbon tube (MWNT) heteromat-mediated ultrahigh capacitance electrode sheets as an unusual electrode architecture strategy to address the aforementioned issue. Vanadium pentoxide (V2O5) is chosen as a model electrode material to explore the feasibility of the suggested concept. The heteromat V2O5 electrode sheets are produced through one-pot fabrication based on concurrent electrospraying (for V2O5 precursor/MWNT) and electrospinning (for PAN nanofiber) followed by calcination, leading to compact packing of V2O5 materials in intimate contact with MWNTs and PAN nanofibers. As a consequence, the heteromat V2O5 electrode sheets offer three-dimensionally bicontinuous electron (arising from MWNT networks)/ion (from spatially reticulated interstitial voids to be filled with liquid electrolytes) conduction pathways, thereby facilitating redox reaction kinetics of V2O5 materials. In addition, elimination of heavy metallic foil current collectors, in combination with the dense packing of V2O5 materials, significantly increases (electrode sheet-based) specific capacitances far beyond those accessible with conventional slurry-cast electrodes.

  1. Electrochromic device based on electrospun WO{sub 3} nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Dulgerbaki, Cigdem; Maslakci, Neslihan Nohut; Komur, Ali Ihsan; Oksuz, Aysegul Uygun, E-mail: ayseguluygun@sdu.edu.tr

    2015-12-15

    Highlights: • WO{sub 3} electrochromic nanofibers were prepared by electrospinning technique. • WO{sub 3} nanofibers switched reversibly from transparent to blue color. • Electrochromic device was assembled using ionic liquid based gel electrolyte. • Significant optical modulation and excellent cycling stability were achieved for ECD. - Abstract: The tungsten oxide (WO{sub 3}) nanofibers were grown directly onto an ITO-coated glass via an electrospinning method for electrochromic applications. The electrochromic properties of WO{sub 3} nanofibers were investigated in the presence of different electrolytes including a series of ionic liquids and classic LiClO{sub 4}-PC system. A significant optical modulation of 20.82% at 760 nm, reversible coloration with efficiency of 64.58 cm{sup 2}/C and excellent cycling stability were achieved for the nanofiber electrochromic device (ECD) with ionic liquid based gel electrolyte.

  2. Electrospun nanofibers: New generation materials for advanced applications

    Energy Technology Data Exchange (ETDEWEB)

    Thenmozhi, S. [Inorganic & Nanomaterials Research Laboratory, Department of Chemistry, Bharathiar University, Coimbatore 641 046 (India); DRDO-BU CLS, Bharathiar University Campus, Coimbatore 641 046 (India); Dharmaraj, N., E-mail: dharmaraj@buc.edu.in [Inorganic & Nanomaterials Research Laboratory, Department of Chemistry, Bharathiar University, Coimbatore 641 046 (India); Kadirvelu, K. [DRDO-BU CLS, Bharathiar University Campus, Coimbatore 641 046 (India); Kim, Hak Yong [Department of Textile Engineering, Chonbuk National University, Chonju 561-756 (Korea, Republic of)

    2017-03-15

    Highlights: • A review covering important aspects of electrospinning technique is presented. • Applications of nanofibers in various fields are reviewed. • Possibility to up-scale electrospinning technique to industry also included. - Abstract: Electrospinning (E-spin) is a unique technique to fabricate polymeric as well as metal oxide nanofibers. Research on electrospun nanofibers is a very active field in material science owing to their novel applications in diverse domains. The main focus of this review is to provide an insight into E-spin technique by understanding the working principle, influencing parameters and applications of nanofibers in different walks of life. Several hundreds of papers are published on the preparation, modification and applications of nanofibers produced by E-spin technique in the areas like sensor development, decontamination, energy storage, biomedical and catalysis etc. Details on the industrial scale development of E-spin technique, current scenario and future developments are also covered in this review.

  3. Fluorescent and Colorimetric Electrospun Nanofibers for Heavy-Metal Sensing

    Directory of Open Access Journals (Sweden)

    Idelma A. A. Terra

    2017-12-01

    Full Text Available The accumulation of heavy metals in the human body and/or in the environment can be highly deleterious for mankind, and currently, considerable efforts have been made to develop reliable and sensitive techniques for their detection. Among the detection methods, chemical sensors appear as a promising technology, with emphasis on systems employing optically active nanofibers. Such nanofibers can be obtained by the electrospinning technique, and further functionalized with optically active chromophores such as dyes, conjugated polymers, carbon-based nanomaterials and nanoparticles, in order to produce fluorescent and colorimetric nanofibers. In this review we survey recent investigations reporting the use of optically active electrospun nanofibers in sensors aiming at the specific detection of heavy metals using colorimetry and fluorescence methods. The examples given in this review article provide sufficient evidence of the potential of optically electrospun nanofibers as a valid approach to fabricate highly selective and sensitive optical sensors for fast and low-cost detection of heavy metals.

  4. Recognition of lysozyme using surface imprinted bacterial cellulose nanofibers.

    Science.gov (United States)

    Saylan, Yeşeren; Tamahkar, Emel; Denizli, Adil

    2017-11-01

    Here, we developed the lysozyme imprinted bacterial cellulose (Lyz-MIP/BC) nanofibers via the surface imprinting strategy that was designed to recognize lysozyme. This study includes the molecular imprinting method onto the surface of bacterial cellulose nanofibers in the presence of lysozyme by metal ion coordination, as well as further characterizations methods FTIR, SEM and contact angle measurements. The maximum lysozyme adsorption capacity of Lyz-MIP/BC nanofibers was found to be 71 mg/g. The Lyz-MIP/BC nanofibers showed high selectivity for lysozyme towards bovine serum albumin and cytochrome c. Overall, the Lyz-MIP/BC nanofibers hold great potential for lysozyme recognition due to the high binding capacity, significant selectivity and excellent reusability.

  5. Ice sheet in peril

    DEFF Research Database (Denmark)

    Hvidberg, Christine Schøtt

    2016-01-01

    Earth's large ice sheets in Greenland and Antarctica are major contributors to sea level change. At present, the Greenland Ice Sheet (see the photo) is losing mass in response to climate warming in Greenland (1), but the present changes also include a long-term response to past climate transitions...

  6. Mobility Balance Sheet 2009

    International Nuclear Information System (INIS)

    Jorritsma, P.; Derriks, H.; Francke, J.; Gordijn, H.; Groot, W.; Harms, L.; Van der Loop, H.; Peer, S.; Savelberg, F.; Wouters, P.

    2009-06-01

    The Mobility Balance Sheet provides an overview of the state of the art of mobility in the Netherlands. In addition to describing the development of mobility this report also provides explanations for the growth of passenger and freight transport. Moreover, the Mobility Balance Sheet also focuses on a topical theme: the effects of economic crises on mobility. [nl

  7. Bioactive thermoresponsive polyblend nanofiber formulations for wound healing

    Energy Technology Data Exchange (ETDEWEB)

    Pawar, Mahesh D. [Polymer Science and Engineering, National Chemical Laboratory, Homi Bhabha Road, Pashan, Pune 411008 (India); MAEER' s Maharashtra Institute of Pharmacy S. No. 124, MIT Campus Paud Road, Kothrud, Pune 411 038 (India); Rathna, G.V.N., E-mail: rv.gundloori@ncl.res.in [Polymer Science and Engineering, National Chemical Laboratory, Homi Bhabha Road, Pashan, Pune 411008 (India); Agrawal, Shubhang [Polymer Science and Engineering, National Chemical Laboratory, Homi Bhabha Road, Pashan, Pune 411008 (India); Kuchekar, Bhanudas S. [MAEER' s Maharashtra Institute of Pharmacy S. No. 124, MIT Campus Paud Road, Kothrud, Pune 411 038 (India)

    2015-03-01

    The rationale of this work is to develop new bioactive thermoresponsive polyblend nanofiber formulations for wound healing (topical). Various polymer compositions of thermoresponsive, poly(N-isopropylacrylamide), egg albumen and poly(ε-caprolactone) blend solutions with and without a drug [gatifloxacin hydrochloride, Gati] were prepared. Non-woven nanofibers of various compositions were fabricated using an electrospinning technique. The morphology of the nanofibers was analyzed by an environmental scanning electron microscope. The morphology was influenced by the concentration of polymer, drug, and polymer blend composition. Fourier transform infrared spectroscopy analysis showed the shift in bands due to hydrogen ion interactions between polymers and drug. Thermogram of PNIPAM/PCL/EA with Gati recorded a shift in lower critical solution temperature (LCST) and glass transition temperature (T{sub g}) of PNIPAM. Similarly T{sub g} and melting temperature (T{sub m}) of PCL were shifted. X-ray diffraction patterns recorded a decrease in the crystalline state of PCL nanofibers and transformed crystalline drug to an amorphous state. In vitro release study of nanofibers with Gati showed initial rapid release up to 10 h, followed by slow and controlled release for 696 h (29 days). Nanofiber mats with Gati exhibited antibacterial properties to Staphylococcus aureus, supported suitable controlled drug release with in vitro cell viability and in vivo wound healing. - Highlights: • Thermoresponsive and bioactive nanofiber blends of PNIPAM/EA/PCL were fabricated. • Nanofiber blends favored initial rapid release, followed by controlled release. • In vitro cell viability of pure polymers and nanofiber blends was least toxic. • In vivo studies of drug loaded nanofiber mats recorded faster tissue regeneration.

  8. Evaluation of protein adsorption onto a polyurethane nanofiber surface having different segment distributions

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Yuko; Koizumi, Gaku [Frontier Fiber Technology and Science, Graduate School of Engineering, University of Fukui (Japan); Sakamoto, Hiroaki, E-mail: hi-saka@u-fukui.ac.jp [Tenure-Track Program for Innovative Research, University of Fukui (Japan); Suye, Shin-ichiro [Frontier Fiber Technology and Science, Graduate School of Engineering, University of Fukui (Japan)

    2017-02-01

    Electrospinning is well known to be an effective method for fabricating polymeric nanofibers with a diameter of several hundred nanometers. Recently, the molecular-level orientation within nanofibers has attracted particular attention. Previously, we used atomic force microscopy to visualize the phase separation between soft and hard segments of a polyurethane (PU) nanofiber surface prepared by electrospinning. The unstretched PU nanofibers exhibited irregularly distributed hard segments, whereas hard segments of stretched nanofibers prepared with a high-speed collector exhibited periodic structures along the long-axis direction. PU was originally used to inhibit protein adsorption, but because the surface segment distribution was changed in the stretched nanofiber, here, we hypothesized that the protein adsorption property on the stretched nanofiber might be affected. We investigated protein adsorption onto PU nanofibers to elucidate the effects of segment distribution on the surface properties of PU nanofibers. The amount of adsorbed protein on stretched PU nanofibers was increased compared with that of unstretched nanofibers. These results indicate that the hard segment alignment on stretched PU nanofibers mediated protein adsorption. It is therefore expected that the amount of protein adsorption can be controlled by rotation of the collector. - Highlights: • The hard segments of stretched PU nanofibers exhibit periodic structures. • The adsorbed protein on stretched PU nanofibers was increased compared with PU film. • The hard segment alignment on stretched PU nanofibers mediated protein adsorption.

  9. Process Optimization and Emperical Modelling for Electrospun Polyacrylonitrile (PAN) Nanofiber Precursor of Carbon nanofibers

    NARCIS (Netherlands)

    Gu, S.Y.; Gu, S.; Ren, J.; Vancso, Gyula J.

    2005-01-01

    Ultrafine fibers were spun from polyacrylonitrile (PAN)/N,N-dimethyl formamide (DMF) solution as a precursor of carbon nanofibers using a homemade electrospinning set-up. Fibers with diameter ranging from 200 nm to 1200 nm were obtained. Morphology of fibers and distribution of fiber diameter were

  10. Nanographene derived from carbon nanofiber and its application to electric double-layer capacitors

    International Nuclear Information System (INIS)

    Mitani, Satoshi; Sathish, Marappan; Rangappa, Dinesh; Unemoto, Atsushi; Tomai, Takaaki; Honma, Itaru

    2012-01-01

    The fascinating properties of graphene are attracting considerable attention in engineering fields such as electronics, optics, and energy engineering. These properties can be controlled by controlling graphene's structure, e.g., the number of layers and the sheet size. In this study, we synthesized nanosized graphene from a platelet-type carbon nanofiber. The thickness and size of nanographene oxide are around 1 nm and 60 nm and we obtained nanographene by hydrazine reduction of nanographene oxide. We applied the nanographene to an ionic-liquid electric double-layer capacitor (EDLC), which exhibited a much larger capacitance per specific surface area than an EDLC using conventional activated carbon. Furthermore, the capacitance increased significantly with increasing cycle time. After 30th cycle, the capacitance was achieved 130 F g −1 , though the surface area was only 240 m 2 g −1 . These results suggest that nanographene structure induce the capacitance enhancement.

  11. Nonlinear dynamics of thin current sheets

    International Nuclear Information System (INIS)

    Daughton, William

    2002-01-01

    Observations indicate that the current sheet in the Earth's geomagnetic tail may compress to a thickness comparable to an ion gyro-radius prior to substorm onset. In recent years, there has been considerable controversy regarding the kinetic stability of these thin structures. In particular, the growth rate of the kink instability and its relevance to magnetotail dynamics is still being debated. In this work, a series of fully kinetic particle-in-cell simulations are performed for a thin Harris sheet. The ion to electron mass ratio is varied between m i /m e =4→400 and careful comparisons are made with a formally exact approach to the linear Vlasov theory. At low mass ratio m i /m e <64, the simulations are in excellent agreement with the linear theory, but at high mass ratio the kink instability is observed to grow more rapidly in the kinetic simulations than predicted by theory. The resolution to this apparent discrepancy involves the lower hybrid instability which is active on the edge of the sheet and rapidly produces nonlinear modifications to the initial equilibrium. The nature of this nonlinear deformation is characterized and a simple model is proposed to explain the physics. After the growth and saturation of the lower hybrid fluctuations, the deformed current sheet is similar in structure to a Harris equilibrium with an additional background population. This may explain the large growth rate of the kink instability at later times, since this type of modification to the Harris sheet has been shown to greatly enhance the growth rate of the kink mode

  12. Carbon sheet pumping

    International Nuclear Information System (INIS)

    Ohyabu, N.; Sagara, A.; Kawamura, T.; Motojima, O.; Ono, T.

    1993-07-01

    A new hydrogen pumping scheme has been proposed which controls recycling of the particles for significant improvement of the energy confinement in toroidal magnetic fusion devices. In this scheme, a part of the vacuum vessel surface near the divertor is covered with carbon sheets of a large surface area. Before discharge initiation, the sheets are baked up to 700 ∼ 1000degC to remove the previously trapped hydrogen atoms. After being cooled down to below ∼ 200degC, the unsaturated carbon sheets trap high energy charge exchange hydrogen atoms effectively during a discharge and overall pumping efficiency can be as high as ∼ 50 %. (author)

  13. Liquid-phase synthesis of Ni nanowire/cellulose hybrid structure

    Science.gov (United States)

    Rahmah Shamsuri, Siti; Shiomi, Shohei; Matsubara, Eiichiro

    2018-02-01

    One-dimensional (1D) nanomaterials (nanowires or nanofibers) are superior to conventional zero-dimensional (0D) nanomaterials (nanoparticles). 1D nanomaterials offer not only the benefits of 0D nanomaterials, such as a large surface area and numerous active sites, but also the capability to prepare macroscopic free-standing and flexible structures owing to their formability to form a sheet. For practical applications, it is essential to develop a simple and easy method of synthesizing 1D nanomaterials. In the present work, a nickel nanowire/cellulose hybrid structure is successfully fabricated via a single-batch liquid-phase reduction method under a magnetic field. The product is not a simple 1D or two-dimensional (2D) structure, but an intricately entangled and interconnected three-dimensional (3D) structure. Fine nickel nanowires are grown from nickel nanoparticles that are heterogeneously nucleated on the surface of a cellulose fiber by using its chemical properties that attract nickel ions.

  14. Development of Protective Clothing against Nanoparticle Based on Electrospun Nanofibers

    Directory of Open Access Journals (Sweden)

    M. Faccini

    2012-01-01

    Full Text Available In this paper, the development of efficient protective clothing against nanoparticulate aerosols is presented. Nanofibrous mats of polyamide 6 (PA6 were deposited onto a nonwoven viscose substrate by electrospinning technique. The influence of electrospinning parameters, including solution concentration, viscosity, and conductivity, was studied for the production of nonwovens with controlled fiber diameter showing a size distribution ranging from 66 to 195 nm. By varying several process parameters, textiles with different thickness of the nanofiber layer and thus air permeability were obtained. A hot-press lamination process using a thermoplastic resin as glue was applied to improve the adhesion of the nanofiber layer onto the textile support. After 1500 cycles of repeated compression and torsion, the nanofiber layer was still firmly attached to the support, while mechanical damage is visible in some areas. The penetration of NaCl particles with diameter ranging from 15 to 300 nm through the electrospun textiles was found to be strongly dependent on nanofiber layer thickness. A really thin nanofiber coating provides up to 80% retention of 20 nm size particles and over 50% retention of 200 nm size nanoparticles. Increasing the thickness of the nanofiber mat, the filtration efficiency was increased to over 99% along the whole nanoparticle range. The results obtained highlight the potential of nanofibers in the development of efficient personal protective equipments against nanoparticles.

  15. Synthesis and Property of Ag(NP)/catechin/Gelatin Nanofiber

    Science.gov (United States)

    Nasir, Muhamad; Apriani, Dita

    2017-12-01

    Nanomaterial play important role future industry such as for the medical, food, pharmaceutical and cosmetic industry. Ag (NP) and catechin exhibit antibacterial property. Ag(NP) with diameter around 15 nm was synthesis by microwaved method. We have successfully produce Ag(NP)/catechin/gelatin nanofiber composite by electrospinning process. Ag(NP)/catechin/gelatin nanofiber was synthesized by using gelatin from tuna fish, polyethylene oxide (PEO), acetic acid as solvent and silver nanoparticle(NP)/catechin as bioactive component, respectively. Morphology and structure of bioactive catechin-gelatin nanofiber were characterized by scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR), respectively. SEM analysis showed that morphology of nanofiber composite was smooth and had average diameter 398.97 nm. FTIR analysis results were used to confirm structure of catechin-gelatin nanofiber. It was confirmed by FTIR that specific vibration band peak amide A (N-H) at 3286,209 cm-1, amide B (N-H) 3069,396 cm-1, amide I (C=O) at 1643,813 cm-1, amide II (N-H and CN) at 1538,949 cm-1, amide III (C-N) at 1276,789 cm-1, C-O-C from polyethylene oxide at 1146,418 cm-1, respectively. When examined to S. Aureus bacteria, Ag/catechin/gelatin nanofiber show inhabitation performance around 40.44%. Ag(NP)/catechin/gelatin nanofiber has potential application antibacterial medical application.

  16. Genotoxicity of carbon nanofibers: Are they potentially more or less dangerous than carbon nanotubes or asbestos?

    International Nuclear Information System (INIS)

    Kisin, E.R.; Murray, A.R.; Sargent, L.; Lowry, D.; Chirila, M.; Siegrist, K.J.; Schwegler-Berry, D.; Leonard, S.; Castranova, V.; Fadeel, B.; Kagan, V.E.; Shvedova, A.A.

    2011-01-01

    The production of carbon nanofibers and nanotubes (CNF/CNT) and their composite products is increasing globally. CNF are generating great interest in industrial sectors such as energy production and electronics, where alternative materials may have limited performance or are produced at a much higher cost. However, despite the increasing industrial use of carbon nanofibers, information on their potential adverse health effects is limited. In the current study, we examine the cytotoxic and genotoxic potential of carbon-based nanofibers (Pyrograf (registered) -III) and compare this material with the effects of asbestos fibers (crocidolite) or single-walled carbon nanotubes (SWCNT). The genotoxic effects in the lung fibroblast (V79) cell line were examined using two complementary assays: the comet assay and micronucleus (MN) test. In addition, we utilized fluorescence in situ hybridization to detect the chromatin pan-centromeric signals within the MN indicating their origin by aneugenic (chromosomal malsegregation) or clastogenic (chromosome breakage) mechanisms. Cytotoxicity tests revealed a concentration- and time-dependent loss of V79 cell viability after exposure to all tested materials in the following sequence: asbestos > CNF > SWCNT. Additionally, cellular uptake and generation of oxygen radicals was seen in the murine RAW264.7 macrophages following exposure to CNF or asbestos but not after administration of SWCNT. DNA damage and MN induction were found after exposure to all tested materials with the strongest effect seen for CNF. Finally, we demonstrated that CNF induced predominately centromere-positive MN in primary human small airway epithelial cells (SAEC) indicating aneugenic events. Further investigations are warranted to elucidate the possible mechanisms involved in CNF-induced genotoxicity.

  17. New High-Energy Nanofiber Anode Materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiangwu [North Carolina State Univ., Raleigh, NC (United States); Fedkiw, Peter [North Carolina State Univ., Raleigh, NC (United States); Khan, Saad [North Carolina State Univ., Raleigh, NC (United States); Huang, Alex [North Carolina State Univ., Raleigh, NC (United States); Fan, Jiang [North Carolina State Univ., Raleigh, NC (United States)

    2013-11-15

    The overall goal of the proposed work was to use electrospinning technology to integrate dissimilar materials (lithium alloy and carbon) into novel composite nanofiber anodes, which simultaneously had high energy density, reduced cost, and improved abuse tolerance. The nanofiber structure allowed the anodes to withstand repeated cycles of expansion and contraction. These composite nanofibers were electrospun into nonwoven fabrics with thickness of 50 μm or more, and then directly used as anodes in a lithium-ion battery. This eliminated the presence of non-active materials (e.g., conducting carbon black and polymer binder) and resulted in high energy and power densities. The nonwoven anode structure also provided a large electrode-electrolyte interface and, hence, high rate capacity and good lowtemperature performance capability. Following are detailed objectives for three proposed project periods. During the first six months: Obtain anodes capable of initial specific capacities of 650 mAh/g and achieve ~50 full charge/discharge cycles in small laboratory scale cells (50 to 100 mAh) at the 1C rate with less than 20 percent capacity fade; In the middle of project period: Assemble, cycle, and evaluate 18650 cells using proposed anode materials, and demonstrate practical and useful cycle life (750 cycles of ~70% state of charge swing with less than 20% capacity fade) in 18650 cells with at least twice improvement in the specific capacity than that of conventional graphite electrodes; At the end of project period: Deliver 18650 cells containing proposed anode materials, and achieve specific capacities greater than 1200 mAh/g and cycle life longer than 5000 cycles of ~70% state of charge swing with less than 20% capacity fade.

  18. Electrochemical fabrication and electronic behavior of polypyrrole nano-fiber array devices

    International Nuclear Information System (INIS)

    Liu Ling; Zhao Yaomin; Jia Nengqin; Zhou Qin; Zhao Chongjun; Yan Manming; Jiang Zhiyu

    2006-01-01

    Electrochemically active Polypyrrole (PPy) nano-fiber array device was fabricated via electrochemical deposition method using aluminum anodic oxide (AAO) membrane as template. After alkaline treatment electrochemically active PPy nano-fiber lost electrochemical activity, and became electrochemically inactive PPy. The electronic properties of PPy nano-fiber array devices were measured by means of a simple method. It was found that for an indium-tin oxide/electrochemically inactive PPy nano-fiber device, the conductivity of nano-fiber increased with the increase of voltage applied on the two terminals of nano-fiber. The electrochemical inactive PPy nano-fiber might be used as a nano-fiber switching diode. Both Au/electrochemically active PPy and Au/electrochemically inactive PPy nano-fiber devices demonstrate rectifying behavior, and might have been used for further application as nano-rectifiers

  19. Electrochemical fabrication and electronic behavior of polypyrrole nano-fiber array devices

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Liu [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Yaomin, Zhao [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Nengqin, Jia [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Qin, Zhou [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Chongjun, Zhao [Photon Craft Project, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences and Japan Science and Technology Agency, Shanghai 201800 (China); Manming, Yan [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Zhiyu, Jiang [Department of Chemistry, and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China)

    2006-05-01

    Electrochemically active Polypyrrole (PPy) nano-fiber array device was fabricated via electrochemical deposition method using aluminum anodic oxide (AAO) membrane as template. After alkaline treatment electrochemically active PPy nano-fiber lost electrochemical activity, and became electrochemically inactive PPy. The electronic properties of PPy nano-fiber array devices were measured by means of a simple method. It was found that for an indium-tin oxide/electrochemically inactive PPy nano-fiber device, the conductivity of nano-fiber increased with the increase of voltage applied on the two terminals of nano-fiber. The electrochemical inactive PPy nano-fiber might be used as a nano-fiber switching diode. Both Au/electrochemically active PPy and Au/electrochemically inactive PPy nano-fiber devices demonstrate rectifying behavior, and might have been used for further application as nano-rectifiers.

  20. A smart core-sheath nanofiber that captures and releases red blood cells from the blood

    Science.gov (United States)

    Shi, Q.; Hou, J.; Zhao, C.; Xin, Z.; Jin, J.; Li, C.; Wong, S.-C.; Yin, J.

    2016-01-01

    A smart core-sheath nanofiber for non-adherent cell capture and release is demonstrated. The nanofibers are fabricated by single-spinneret electrospinning of poly(N-isopropylacrylamide) (PNIPAAm), polycaprolactone (PCL) and nattokinase (NK) solution blends. The self-assembly of PNIPAAm and PCL blends during the electrospinning generates the core-sheath PCL/PNIPAAm nanofibers with PNIPAAm as the sheath. The PNIPAAm-based core-sheath nanofibers are switchable between hydrophobicity and hydrophilicity with temperature change and enhance stability in the blood. When the nanofibers come in contact with blood, the NK is released from the nanofibers to resist platelet adhesion on the nanofiber surface, facilitating the direct capture and isolation of red blood cells (RBCs) from the blood above phase-transition temperature of PNIPAAm. Meanwhile, the captured RBCs are readily released from the nanofibers with temperature stimuli in an undamaged manner. The release efficiency of up to 100% is obtained while maintaining cellular integrity and function. This work presents promising nanofibers to effectively capture non-adherent cells and release for subsequent molecular analysis and diagnosis of single cells.A smart core-sheath nanofiber for non-adherent cell capture and release is demonstrated. The nanofibers are fabricated by single-spinneret electrospinning of poly(N-isopropylacrylamide) (PNIPAAm), polycaprolactone (PCL) and nattokinase (NK) solution blends. The self-assembly of PNIPAAm and PCL blends during the electrospinning generates the core-sheath PCL/PNIPAAm nanofibers with PNIPAAm as the sheath. The PNIPAAm-based core-sheath nanofibers are switchable between hydrophobicity and hydrophilicity with temperature change and enhance stability in the blood. When the nanofibers come in contact with blood, the NK is released from the nanofibers to resist platelet adhesion on the nanofiber surface, facilitating the direct capture and isolation of red blood cells (RBCs) from

  1. Nanofiber Anisotropic Conductive Films (ACF) for Ultra-Fine-Pitch Chip-on-Glass (COG) Interconnections

    Science.gov (United States)

    Lee, Sang-Hoon; Kim, Tae-Wan; Suk, Kyung-Lim; Paik, Kyung-Wook

    2015-11-01

    Nanofiber anisotropic conductive films (ACF) were invented, by adapting nanofiber technology to ACF materials, to overcome the limitations of ultra-fine-pitch interconnection packaging, i.e. shorts and open circuits as a result of the narrow space between bumps and electrodes. For nanofiber ACF, poly(vinylidene fluoride) (PVDF) and poly(butylene succinate) (PBS) polymers were used as nanofiber polymer materials. For PVDF and PBS nanofiber ACF, conductive particles of diameter 3.5 μm were incorporated into nanofibers by electrospinning. In ultra-fine-pitch chip-on-glass assembly, insulation was significantly improved by using nanofiber ACF, because nanofibers inside the ACF suppressed the mobility of conductive particles, preventing them from flowing out during the bonding process. Capture of conductive particles was increased from 31% (conventional ACF) to 65%, and stable electrical properties and reliability were achieved by use of nanofiber ACF.

  2. PLGA nanofiber membranes loaded with epigallocatechin-3-O-gallate are beneficial to prevention of postsurgical adhesions

    Directory of Open Access Journals (Sweden)

    Shin YC

    2014-08-01

    both scavenging reactive oxygen species and extending activated partial thromboplastin time. Macroscopic observation after 1 week of surgical treatment revealed that the antiadhesion efficacy of E-PLGA nanofiber membranes was significantly superior to those of untreated controls and pure PLGA equivalents, which was comparable to that of a commercial tissue-adhesion barrier. In conclusion, the E-PLGA hybrid nanofiber can be exploited to craft strategies for the prevention of postsurgical adhesions. Keywords: nanofiber membrane, poly(lactic-co-glycolic acid, epigallocatechin-3-O-gallate, antiadhesion, tissue-adhesion barrier

  3. The Pine-Needle-Inspired Structure of Zinc Oxide Nanorods Grown on Electrospun Nanofibers for High-Performance Flexible Supercapacitors.

    Science.gov (United States)

    Sami, Syed Kamran; Siddiqui, Saqib; Shrivastava, Sajal; Lee, Nae-Eung; Chung, Chan-Hwa

    2017-12-01

    Flexible supercapacitors with high electrochemical performance and stability along with mechanical robustness have gained immense attraction due to the substantial advancements and rampant requirements of storage devices. To meet the exponentially growing demand of microsized energy storage device, a cost-effective and durable supercapacitor is mandatory to realize their practical applications. Here, in this work, the fabrication route of novel electrode materials with high flexibility and charge-storage capability is reported using the hybrid structure of 1D zinc oxide (ZnO) nanorods and conductive polyvinylidene fluoride-tetrafluoroethylene (P(VDF-TrFE)) electrospun nanofibers. The ZnO nanorods are conformably grown on conductive P(VDF-TrFE) nanofibers to fabricate the light-weighted porous electrodes for supercapacitors. The conductive nanofibers acts as a high surface area scaffold with significant electrochemical performance, while the addition of ZnO nanorods further enhances the specific capacitance by 59%. The symmetric cell with the fabricated electrodes presents high areal capacitance of 1.22 mF cm -2 at a current density of 0.1 mA cm -2 with a power density of more than 1600 W kg -1 . Furthermore, these electrodes show outstanding flexibility and high stability with 96% and 78% retention in specific capacitance after 1000 and 5000 cycles, respectively. The notable mechanical durability and robustness of the cell acquire both good flexibility and high performance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Morphology control between microspheres and nanofibers by solvent-induced approach based on crosslinked phosphazene-containing materials

    International Nuclear Information System (INIS)

    Zhu Yan; Huang Xiaobin; Fu Jianwei; Wang Gang; Tang Xiaozhen

    2008-01-01

    Multi-morphology control between monodisperse microspheres and uniform nanofibers was successfully achieved by adjusting the ratio of solvent composition. Through the condensation polymerization between hexachlorocyclotriphosphazene and 4,4'-sulfonyldiphenol, the corresponding hybrid inorganic-organic materials appeared. The morphology of both microspheres and nanofibers contained excellent size and shape: the monodisperse microspheres with 0.7-0.9 μm in diameter and the uniform nanofibers with 60 nm in outer diameter. We applied the concept of three-dimensional Hansen solubility parameters for the initial explanation. The activity of the primary colloid particles and the solubility of triethylamine-hydrogen chloride crystal were considered as two factors for the mechanism explanation. This interesting research shows that the nano- and micro-materials with high crosslinked molecule structure and prepared by condensation polymerization can also achieve the morphology transition. It fills the blank in nano-morphology transition research and will provide great information for the research about the control of different morphology preparations based on polymer nanomaterials

  5. Anesthesia Fact Sheet

    Science.gov (United States)

    ... Education About NIGMS NIGMS Home > Science Education > Anesthesia Anesthesia Tagline (Optional) Middle/Main Content Area En español ... Version (464 KB) Other Fact Sheets What is anesthesia? Anesthesia is a medical treatment that prevents patients ...

  6. Structural Biology Fact Sheet

    Science.gov (United States)

    ... NIGMS NIGMS Home > Science Education > Structural Biology Structural Biology Tagline (Optional) Middle/Main Content Area PDF Version (688 KB) Other Fact Sheets What is structural biology? Structural biology is the study of how biological ...

  7. Radiation protecting sheet

    International Nuclear Information System (INIS)

    Makiguchi, Hiroshi.

    1989-01-01

    As protection sheets used in radioactivity administration areas, a thermoplastic polyurethane composition sheet with a thickness of less 0.5 mm, solid content (ash) of less than 5% and a shore D hardness of less than 60 is used. A composite sheet with thickness of less than 0.5 mm laminated or coated with such a thermoplastic polyurethane composition as a surface layer and the thermoplastic polyurethane composition sheet applied with secondary fabrication are used. This can satisfy all of the required properties, such as draping property, abrasion resistance, high breaking strength, necking resistance, endurance strength, as well as chemical resistance and easy burnability in burning furnace. Further, by forming uneveness on the surface by means of embossing, etc. safety problems such as slippage during operation and walking can be overcome. (T.M.)

  8. Global ice sheet modeling

    International Nuclear Information System (INIS)

    Hughes, T.J.; Fastook, J.L.

    1994-05-01

    The University of Maine conducted this study for Pacific Northwest Laboratory (PNL) as part of a global climate modeling task for site characterization of the potential nuclear waste respository site at Yucca Mountain, NV. The purpose of the study was to develop a global ice sheet dynamics model that will forecast the three-dimensional configuration of global ice sheets for specific climate change scenarios. The objective of the third (final) year of the work was to produce ice sheet data for glaciation scenarios covering the next 100,000 years. This was accomplished using both the map-plane and flowband solutions of our time-dependent, finite-element gridpoint model. The theory and equations used to develop the ice sheet models are presented. Three future scenarios were simulated by the model and results are discussed

  9. Enhanced thermal conductance of polymer composites through embeddingaligned carbon nanofibers

    Directory of Open Access Journals (Sweden)

    Dale K. Hensley

    2016-07-01

    Full Text Available The focus of this work is to find a more efficient method of enhancing the thermal conductance of polymer thin films. This work compares polymer thin films embedded with randomly oriented carbon nanotubes to those with vertically aligned carbon nanofibers. Thin films embedded with carbon nanofibers demonstrated a similar thermal conductance between 40–60 μm and a higher thermal conductance between 25–40 μm than films embedded with carbon nanotubes with similar volume fractions even though carbon nanotubes have a higher thermal conductivity than carbon nanofibers.

  10. Preparation and Electrochemical Properties of Silver Doped Hollow Carbon Nanofibers

    Directory of Open Access Journals (Sweden)

    LI Fu

    2016-11-01

    Full Text Available Silver doped PAN-based hollow carbon nanofibers were prepared combining co-electrospinning with in situ reduction technique subsequently heat treatment to improve the electrochemical performances of carbon based supercapacitor electrodes. The morphology, structure and electrochemical performances of the resulted nanofiber were studied. The results show that the silver nanoparticles can be doped on the surface of hollow carbon nanofibers and the addition of silver favors the improvement of the electrochemical performances, exhibiting the enhanced reversibility of electrode reaction and the capacitance and the reduced charge transfer impedance.

  11. Solution-blown nanofiber mats from fish sarcoplasmic protein

    DEFF Research Database (Denmark)

    Sett, S.; Boutrup Stephansen, Karen; Yarin, A.L.

    2016-01-01

    In the present work, solution-blowing was adopted to form nanofibers from fish sarcoplasmic proteins (FSPs). Nanofiber mats containing different weight ratios (up to 90/10) of FSP in the FSP/nylon 6 blended nanofibers were formed from formic acid solutions, and compared to electrospun fibers made...... that the production rate of solution-blowing was increased 30-fold in relation to electrospinning. Overall, this study reveals FSP as an interesting biopolymeric alternative to synthetic polymers, and the introduction of FSP to nylon 6 provides a composite with controlled properties....

  12. Growth and Integration of Organic Nanofibers in Devices

    DEFF Research Database (Denmark)

    Thilsing-Hansen, Kasper

    kæder af krystalliter, der tilslutter sig den allerede eksisterende P6P nanofiber. Overførsel af P6P nanofibre fra deres vækst substrat er uundgåeligt for at implementere p6P nanofibre i komponenter. Kontrolleret overførsel af 200x200μm2 nanofiber områder fra vækst substratet til præfabrikerede silicium......) exciteret med en pulserende laserstråle et guld/vakuum interface, hvilket resulterer i nanofiber lokaliseret mønstre i PEEM billederne....

  13. Energy information sheets

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the public. The Energy Information Sheets was developed to provide general information on various aspects of fuel production, prices, consumption, and capability. Additional information on related subject matter can be found in other Energy Information Administration (EIA) publications as referenced at the end of each sheet.

  14. Electrospun carbon nanofibers surface-grafted with vapor-grown carbon nanotubes as hierarchical electrodes for supercapacitors

    Science.gov (United States)

    Zhou, Zhengping; Wu, Xiang-Fa; Fong, Hao

    2012-01-01

    This letter reports the fabrication and electrochemical properties of electrospun carbon nanofibers surface-grafted with vapor-grown carbon nanotubes (CNTs) as hierarchical electrodes for supercapacitors. The specific capacitance of the fabricated electrodes was measured up to 185 F/g at the low discharge current density of 625 mA/g; a decrease of 38% was detected at the high discharge current density of 2.5 A/g. The morphology and microstructure of the electrodes were examined by electron microscopy, and the unique connectivity of the hybrid nanomaterials was responsible for the high specific capacitance and low intrinsic contact electric resistance of the hierarchical electrodes.

  15. Bioactive nanofibers for fibroblastic differentiation of mesenchymal precursor cells for ligament/tendon tissue engineering applications.

    Science.gov (United States)

    Sahoo, Sambit; Ang, Lay-Teng; Cho-Hong Goh, James; Toh, Siew-Lok

    2010-02-01

    Mesenchymal stem cells and precursor cells are ideal candidates for tendon and ligament tissue engineering; however, for the stem cell-based approach to succeed, these cells would be required to proliferate and differentiate into tendon/ligament fibroblasts on the tissue engineering scaffold. Among the various fiber-based scaffolds that have been used in tendon/ligament tissue engineering, hybrid fibrous scaffolds comprising both microfibers and nanofibers have been recently shown to be particularly promising. With the nanofibrous coating presenting a biomimetic surface, the scaffolds can also potentially mimic the natural extracellular matrix in function by acting as a depot for sustained release of growth factors. In this study, we demonstrate that basic fibroblast growth factor (bFGF) could be successfully incorporated, randomly dispersed within blend-electrospun nanofibers and released in a bioactive form over 1 week. The released bioactive bFGF activated tyrosine phosphorylation signaling within seeded BMSCs. The bFGF-releasing nanofibrous scaffolds facilitated BMSC proliferation, upregulated gene expression of tendon/ligament-specific ECM proteins, increased production and deposition of collagen and tenascin-C, reduced multipotency of the BMSCs and induced tendon/ligament-like fibroblastic differentiation, indicating their potential in tendon/ligament tissue engineering applications. 2009 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

  16. Waveguiding properties of individual electrospun polymer nanofibers

    Science.gov (United States)

    Ishii, Yuya; Kaminose, Ryohei; Fukuda, Mitsuo

    2013-09-01

    Optical circuits are needed to achieve high-speed, high-capacity information processing. An optical waveguide is an essential element in optical circuits. Electrospun polymer fibers have diameters in the nanometer range and high aspect ratios, so they are prime candidates for small waveguides. In this work, we fabricate uniform electrospun polymer nanofibers and characterize their optical waveguiding properties. Poly(methyl methacrylate) (PMMA) solutions of different concentration that contain a small amount of Nile Blue A perchlorate (NBA) are electrospun. Uniform PMMA/NBA nanofibers are obtained from the 10 wt% solution. The fibers are covered with transparent cladding and their ends cut vertically. A laser beam with a wavelength of 533 nm is irradiated onto the fiber from the direction vertical to the fiber axis so that it scans along the fiber. Photoluminescence (PL) at the end face of individual fibers is then measured. The PL intensity decreases with increasing distance (d) between the end face of a fiber and irradiating point of the laser beam as ~exp(-αd) with a loss coefficient (α). Measurements of five individual fibers reveal α is in the range of 17-75 cm-1.

  17. Biosynthesis of highly porous bacterial cellulose nanofibers

    Science.gov (United States)

    Hosseini, Hadi; Kokabi, Mehrdad; Mousavi, Seyyed Mohammad

    2018-01-01

    Bacterial cellulose nanofibers (BCNFs) as a sustainable and biodegradable polymer has drawn tremendous research attention in tissue engineering, bacterial sensors and drug delivery due to its extraordinary properties such as high purity, high crystallinity, high water absorption capacity and excellent mechanical strength in the wet state. This awesome properties, is attributed to BCNFs structure, therefore its characterization is important. In this work, the bacterial strain, Gluconacetobacter xylinus (PTCC 1734, obtained from Iranian Research Organization for Science and Technology (IROST)), was used to produce BCNFs hydrogel using bacterial fermentation under static condition at 29 °C for 10 days in the incubator. Then, the biosynthesized BCNFs wet gel, were dried at ambient temperature and pressure and characterized using Brunauer-Emmett-Teller (BET) and Field emission scanning electron microscopy (FE-SEM) analysis. FESEM image displayed highly interconnected and porous structure composed of web-like continuous, nanofibers with an average diameter of 48.5±2.1 nm. BET result analysis depicted BCNFs dried at ambient conditions had IV isotherm type, according to the IUPAC classification, indicating that BCNFs dried at ambient condition is essentially mesoporous. On the other hand, BET results depicted, mesoporous structure is around 85%. In addition, Specific surface area (SBET) obtained 81.45 m2/g. These results are in accordance with the FESEM observation.

  18. Improved efficiency in organic/inorganic hybrid solar cells by interfacial modification of ZnO nanowires with small molecules

    International Nuclear Information System (INIS)

    Chang, Sehoon; Park, Hyesung; Cheng, Jayce J; Rekemeyer, Paul H; Gradečak, Silvija

    2014-01-01

    We demonstrate improved photovoltaic performance of ZnO nanowire/poly(3-hexylthiophene) (P3HT) nanofiber hybrid devices using an interfacial modification of ZnO nanowires. Formation of cascade energy levels between the ZnO nanowire and P3HT nanofiber was achieved by interfacial modification of ZnO nanowires using small molecules tetraphenyldibenzoperiflanthene (DBP) and 3,4,9,10-perylenetetracarboxylic bisbenzimidazole (PTCBI). The successful demonstration of improved device performance owing to the cascade energy levels by small molecule modification is a promising approach toward highly efficient organic/inorganic hybrid solar cells. (paper)

  19. Method of synthesizing silica nanofibers using sound waves

    Science.gov (United States)

    Sharma, Jaswinder K.; Datskos, Panos G.

    2015-09-15

    A method for synthesizing silica nanofibers using sound waves is provided. The method includes providing a solution of polyvinyl pyrrolidone, adding sodium citrate and ammonium hydroxide to form a first mixture, adding a silica-based compound to the solution to form a second mixture, and sonicating the second mixture to synthesize a plurality of silica nanofibers having an average cross-sectional diameter of less than 70 nm and having a length on the order of at least several hundred microns. The method can be performed without heating or electrospinning, and instead includes less energy intensive strategies that can be scaled up to an industrial scale. The resulting nanofibers can achieve a decreased mean diameter over conventional fibers. The decreased diameter generally increases the tensile strength of the silica nanofibers, as defects and contaminations decrease with the decreasing diameter.

  20. Interfacial Synthesis of Electrically Conducting Polyaniline Nanofiber Composites

    National Research Council Canada - National Science Library

    Hopkins, A

    2004-01-01

    .... The in-situ polymerization technique of these PANI nanofibers in the presence of sulfonated polystyrene allowed for the growth of PANI 2-D nanostructures embedded in the polymerized sulfonated host...

  1. Interfacial Polymerization of Polyaniline Nanofibers Grafted to Au Surfaces

    National Research Council Canada - National Science Library

    Sawall, D

    2004-01-01

    .... The in-situ polymerization technique of these PANI nanofibers in the presence of sulfonated polystyrene allowed for the growth of PANI 2-D nanostructures embedded in the polymerized sulfonated host...

  2. Multicolored Nanofiber Based Organic Light-Emitting Transistor

    DEFF Research Database (Denmark)

    With Jensen, Per Baunegaard; Kjelstrup-Hansen, Jakob; Tavares, Luciana

    For optoelectronic applications, organic semiconductors have several advantages over their inorganic counterparts such as facile synthesis, tunability via synthetic chemistry, and low temperature processing. Self-assembled, molecular crystalline nanofibers are of particular interest as they could...... form ultra-small light-emitters in future nanophotonic applications. Such organic nanofibers exhibit many interesting optical properties including polarized photo- and electroluminescence, waveguiding, and emission color tunability. We here present a first step towards a multicolored, electrically...... driven device by combining nanofibers made from two different molecules, parahexaphenylene (p6P) and 5,5´-Di-4-biphenyl-2,2´-bithiophene (PPTTPP), which emits blue and green light, respectively. The organic nanofibers are implemented on a bottom gate/bottom contact field-effect transistor platform using...

  3. A modified microemulsion method for fabrication of hydrogel Tragacanth nanofibers.

    Science.gov (United States)

    Ghayempour, Soraya; Montazer, Majid

    2018-04-09

    Tragacanth is a nontoxic, biodegradable and biocompatible polymer applied as a nanostructure form in various fields such as biomedicine and food industry. Here, hydrogel Tragacanth nanofibers were fabricated using a modified microemulsion method. The effective parameters on the fabrication of nanofibers such as emulsifier type, stirrer type, processing time and concentrations of emulsifier, Tragacanth and aluminum chloride were studied and the conditions were optimized for high quality nanofibers. SEM images indicated Tragacanth nanofiberswere successfully synthesized with average diameter of 50 nm and uniformdistribution. Appear a peak at 1110 cm -1 related to Al-C bonds and reduce intensity ofthe peaks at 1742 and 1629 cm -1 and in FT-IR spectrum of nanofibersprove the successfully synthesis. Further, the hydrogel properties of the synthesized nanofibers can be proved by the swelling of 142% and drying time of 3 h. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. A review on electrospun nanofibers for oral drug delivery

    Directory of Open Access Journals (Sweden)

    Abbas Akhgari

    2017-10-01

    Full Text Available Nowadays, polymer nanofibers have gained attention due to remarkable characteristics such as high porosity and large surface area to volume ratio. Among their fabrication methods, electrospinning technique has been attracted as a simple and reproducible approach. It is a versatile, simple and cost-effective technique for the production of continuous nanofibers with acceptable characteristics such as high porosity, high surface area to volume ratio, high loading capacity and encapsulation efficiency, delivery of multiple drugs, and enhancement of drug solubility. Due to these properties electrospun nanofibers have been extensively used for different biomedical applications including wound dressing, tissue engineering, enzyme immobilization, artificial organs, and drug delivery. Different synthetic and natural polymers have been successfully electrospun into ultrafine fibers. Using electrospun nanofibers as vehicles for oral drug delivery has been investigated in different release manners- fast, biphasic or sustained release. This article presents a review on application of electrospinning technique in oral drug delivery.

  5. Nanofibrous nonwovens based on dendritic-linear-dendritic poly(ethylene glycol) hybrids

    DEFF Research Database (Denmark)

    Kikionis, Stefanos; Ioannou, Efstathia; Andren, Oliver C.J.

    2017-01-01

    unsuccessful. Nevertheless, when these DLD hybrids were blended with an array of different biodegradable polymers as entanglement enhancers, nanofibrous nonwovens were successfully prepared by electrospinning. The pseudogeneration degree of the DLDs, the nature of the co-electrospun polymer and the solvent...... nanofibers. Such dendritic nanofibrous scaffolds can be promising materials for biomedical applications due to their biocompatibility, biodegradability, multifunctionality, and advanced structural architecture....

  6. High temperature resistant nanofiber by bubbfil-spinning

    Directory of Open Access Journals (Sweden)

    Li Ya

    2015-01-01

    Full Text Available Heat-resisting nanofibers have many potential applications in various industries, and the bubbfil spinning is the best candidate for mass-production of such materials. Polyether sulfone/zirconia solution with a bi-solvent system is used in the experiment. Experimental result reveals that polyether sulfone/zirconia nanofibers have higher resistance to high temperature than pure polyether sulfone fibers, and can be used as high-temperature-resistant filtration materials.

  7. A review on electrospun nanofibers for oral drug delivery

    OpenAIRE

    Abbas Akhgari; Zahra Shakib; Setareh Sanati

    2017-01-01

    Nowadays, polymer nanofibers have gained attention due to remarkable characteristics such as high porosity and large surface area to volume ratio. Among their fabrication methods, electrospinning technique has been attracted as a simple and reproducible approach. It is a versatile, simple and cost-effective technique for the production of continuous nanofibers with acceptable characteristics such as high porosity, high surface area to volume ratio, high loading capacity and encapsulation effi...

  8. Polyurethane Nanofiber Membranes for Waste Water Treatment by Membrane Distillation

    OpenAIRE

    Jiříček, T.; Komárek, M.; Lederer, T.

    2017-01-01

    Self-sustained electrospun polyurethane nanofiber membranes were manufactured and tested on a direct-contact membrane distillation unit in an effort to find the optimum membrane thickness to maximize flux rate and minimize heat losses across the membrane. Also salt retention and flux at high salinities up to 100 g kg−1 were evaluated. Even though the complex structure of nanofiber layers has extreme specific surface and porosity, membrane performance was surprisingly predictable; the highest ...

  9. Improvement of air permeability of Bubbfil nanofiber membrane

    Directory of Open Access Journals (Sweden)

    Wang Fei-Yan

    2018-01-01

    Full Text Available Nanofiber membranes always have extremely high filter efficiency and remarkably low pressure drop. In order to further improve air permeability of bubbfil nanofiber membranes, the plasma technology is used for surface treatment in this paper. The results show that plasma treatment can improve air permeability by 4.45%. Under higher power plasma treatment, earthworm like etchings are produced on the membrane surface with fractal dimensions of about 1.138.

  10. Antibacterial polylactic acid/chitosan nanofibers decorated with bioactive glass

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Yi-fan; Akram, Muhammad; Alshemary, Ammarz [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Hussain, Rafaqat, E-mail: rafaqat@comsats.edu.pk [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan)

    2016-11-30

    Highlights: • PLA/Chitosan nanofibers were coated with functional bioglass. • Polymer/ceramic composite fibers exhibited good in-vitro bioactivity. • Nanofibers coated with Ag doped bioglass exhibited good antibacterial activity. - Abstract: In this study, we have presented the structural and in vitro characterization of electrospun polylactic acid (PLA)/Chitosan nanofibers coated with cerium, copper or silver doped bioactive glasses (CeBG/CuBG/AgBG). Bead-free, smooth surfaced nanofibers were successfully prepared by using electrospinning technique. The nanocomposite fibers were obtained using a facile dip-coating method, their antibacterial activities against E. coliE. coli (ATCC 25922 strains) were measured by the disk diffusion method after 24 h of incubation at 37 °C. CeBG and CuBG decorated PLA/Chitosan nanofibers did not develop an inhibition zone against the bacteria. On the other hand, nanofibers coated with AgBG developed an inhibition zone against the bacteria. The as-prepared nanocomposite fibers were immersed in SBF for 1, 3 and 7 days in Simulated Body Fluid (SBF) for evaluation of in vitro bioactivity. All samples induced the formation of crystallites with roughly ruffled morphology and the pores of fibers were covered with the extensive growth of crystallites. Energy Dispersive X-ray (EDX) composition analysis showed that the crystallites possessed Ca/P ratio close to 1.67, confirming the good in-vitro bioactivity of the fibers.

  11. Temperature-responsive PLLA/PNIPAM nanofibers for switchable release

    Energy Technology Data Exchange (ETDEWEB)

    Elashnikov, Roman; Slepička, Petr [Department of Solid State Engineering, University of Chemistry and Technology, Prague 166 28 (Czech Republic); Rimpelova, Silvie; Ulbrich, Pavel [Department of Biochemistry and Microbiology, University of Chemistry and Technology, 16628 Prague (Czech Republic); Švorčík, Vaclav [Department of Solid State Engineering, University of Chemistry and Technology, Prague 166 28 (Czech Republic); Lyutakov, Oleksiy, E-mail: lyutakoo@vscht.cz [Department of Solid State Engineering, University of Chemistry and Technology, Prague 166 28 (Czech Republic)

    2017-03-01

    Smart antimicrobial materials with on-demand drug release are highly desired for biomedical applications. Herein, we report about temperature-responsive poly(N-isopropylacrylamide) (PNIPAM) nanospheres doped with crystal violet (CV) and incorporated into the poly-L-lactide (PLLA) nanofibers. The nanofibers were prepared by electrospinning, using different initial polymers ratios. The morphology of the nanofibers and polymers distribution in the nanofibers were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The interaction between PNIPAM and PLLA in the nanofibers was studied by Fourier transform infrared spectroscopy (FTIR) and its effect on the PNIPAM phase transition was also investigated. It was shown that by the changing of the environmental temperature across the lower critical solution temperature (LCST) of PNIPAM, the switchable wettability and controlled CV release can be achieved. The temperature-dependent release kinetics of CV from polymer nanofibers was investigated by ultraviolet-visible spectroscopy (UV–Vis). The temperature-responsive release of antibacterial CV was also tested for triggering of antibacterial activity, which was examined on Staphylococcus epidermidis (S. epidermidis) and Escherichia coli (E. coli). Thus, the proposed material is promising value for controllable drug-release.

  12. ECM Decorated Electrospun Nanofiber for Improving Bone Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Yong Fu

    2018-03-01

    Full Text Available Optimization of nanofiber surface properties can lead to enhanced tissue regeneration outcomes in the context of bone tissue engineering. Herein, we developed a facile strategy to decorate elctrospun nanofibers using extracellular matrix (ECM in order to improve their performance for bone tissue engineering. Electrospun PLLA nanofibers (PLLA NF were seeded with MC3T3-E1 cells and allowed to grow for two weeks in order to harvest a layer of ECM on nanofiber surface. After decellularization, we found that ECM was successfully preserved on nanofiber surface while maintaining the nanostructure of electrospun fibers. ECM decorated on PLLA NF is biologically active, as evidenced by its ability to enhance mouse bone marrow stromal cells (mBMSCs adhesion, support cell proliferation and promote early stage osteogenic differentiation of mBMSCs. Compared to PLLA NF without ECM, mBMSCs grown on ECM/PLLA NF exhibited a healthier morphology, faster proliferation profile, and more robust osteogenic differentiation. Therefore, our study suggests that ECM decoration on electrospun nanofibers could serve as an efficient approach to improving their performance for bone tissue engineering.

  13. Synthesis of Keratin-based Nanofiber for Biomedical Engineering.

    Science.gov (United States)

    Thompson, Zanshe S; Rijal, Nava P; Jarvis, David; Edwards, Angela; Bhattarai, Narayan

    2016-02-07

    Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of these porous nanofibers is of great interest due to their unique physiochemical properties. Here we elaborate on the fabrication of keratin containing poly (ε-caprolactone) (PCL) nanofibers (i.e., PCL/keratin composite fiber). Water soluble keratin was first extracted from human hair and mixed with PCL in different ratios. The blended solution of PCL/keratin was transformed into nanofibrous membranes using a laboratory designed electrospinning set up. Fiber morphology and mechanical properties of the obtained nanofiber were observed and measured using scanning electron microscopy and tensile tester. Furthermore, degradability and chemical properties of the nanofiber were studied by FTIR. SEM images showed uniform surface morphology for PCL/keratin fibers of different compositions. These PCL/keratin fibers also showed excellent mechanical properties such as Young's modulus and failure point. Fibroblast cells were able to attach and proliferate thus proving good cell viability. Based on the characteristics discussed above, we can strongly argue that the blended nanofibers of natural and synthetic polymers can represent an excellent development of composite materials that can be used for different biomedical applications.

  14. Single flexible nanofiber to simultaneously realize electricity-magnetism bifunctionality

    International Nuclear Information System (INIS)

    Yang, Ming; Sheng, Shujuan; Ma, Qianli; Lv, Nan; Yu, Wensheng; Wang, Jinxian; Dong, Xiangting; Liu, Guixia

    2016-01-01

    In order to develop new-typed multifunctional composite nanofibers, PANI/Fe 3 O 4 /PVP flexible bifunctional composite nanofibers with simultaneous electrical conduction and magnetism have been successfully fabricated via a facile electrospinning technology. Polyvinyl pyrrolidone (PVP) is used as a matrix to construct composite nanofibers containing different amounts of polyaniline (PANI) and Fe 3 O 4 nanoparticles (NPs). The bifunctional composite nanofibers simultaneously possess excellent electrical conductivity and magnetic properties. The electrical conductivity reaches up to the order of 10 -3 S·cm -1 . The electrical conductivity and saturation magnetization of the composite nanofibers can be respectively tuned by adding various amounts of PANI and Fe 3 O 4 NPs. The obtained electricity-magnetism bifunctional composite nanofibers are expected to possess many potential applications in areas such as electromagnetic interference shielding, special coating, microwave absorption, molecular electronics and future nanomechanics. More importantly, the design concept and construct technique are of universal significance to fabricate other bifunctional one-dimensional nanostructures. (author)

  15. Single flexible nanofiber to simultaneously realize electricity-magnetism bifunctionality

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ming; Sheng, Shujuan; Ma, Qianli; Lv, Nan; Yu, Wensheng; Wang, Jinxian; Dong, Xiangting; Liu, Guixia, E-mail: wenshengyu2009@sina.com, E-mail: dongxiangting888@163.com [Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun (China)

    2016-03-15

    In order to develop new-typed multifunctional composite nanofibers, PANI/Fe{sub 3}O{sub 4}/PVP flexible bifunctional composite nanofibers with simultaneous electrical conduction and magnetism have been successfully fabricated via a facile electrospinning technology. Polyvinyl pyrrolidone (PVP) is used as a matrix to construct composite nanofibers containing different amounts of polyaniline (PANI) and Fe{sub 3}O{sub 4} nanoparticles (NPs). The bifunctional composite nanofibers simultaneously possess excellent electrical conductivity and magnetic properties. The electrical conductivity reaches up to the order of 10{sup -3} S·cm{sup -1}. The electrical conductivity and saturation magnetization of the composite nanofibers can be respectively tuned by adding various amounts of PANI and Fe{sub 3}O{sub 4} NPs. The obtained electricity-magnetism bifunctional composite nanofibers are expected to possess many potential applications in areas such as electromagnetic interference shielding, special coating, microwave absorption, molecular electronics and future nanomechanics. More importantly, the design concept and construct technique are of universal significance to fabricate other bifunctional one-dimensional nanostructures. (author)

  16. Preparation of Diethylenetriamine Modified Polyacrylonitrile Nanofibers for Cadmium Ion Adsorption

    Directory of Open Access Journals (Sweden)

    Zahra Mokhtari- shorijeh

    2016-07-01

    Full Text Available In this study, the electrospinning method was used to manufacture polyacrylonitrile (PAN nanofibers. The procedure involved spinning a solution of 10%wt PAN in dimethyl formamide (DMF in an electric field of 21 kV and with a tip to collector distance of 16 cm. The nanofibers thus obtained had an average diameter of 100 nm. Then, scanning electron microscopy (SEM images were used to investigate the morphology of the nanofibers. In the next step, the nanofiner surface was modified with diethylenetriamine and FTIR was employed to ensure the presence of amines on the nanofiber surface. The functionalized nanofibers were then used for the first time to adsorb ions of cadmium (a heavy metal with industrial applications and its adsorption capacity was evaluated. The chemical charactristics of the nanofibers and the effects of such parameters as pH, temprature, and contact time on adsorption efficiency were investigated. The results showed that maximum adsorption efficiency was achieved within the first 10 minutes of the process at a pH in the range of 5‒7 when about 80% of the cadmium ions were adsorbed.. Moreover, only slight changes were observed with longer contact times or with increasing temperature. Finally, the adsorption data fitted well with the Langmuir isotherm

  17. Disintegration of liquid sheets

    Science.gov (United States)

    Mansour, Adel; Chigier, Norman

    1990-01-01

    The development, stability, and disintegration of liquid sheets issuing from a two-dimensional air-assisted nozzle is studied. Detailed measurements of mean drop size and velocity are made using a phase Doppler particle analyzer. Without air flow the liquid sheet converges toward the axis as a result of surface tension forces. With airflow a quasi-two-dimensional expanding spray is formed. The air flow causes small variations in sheet thickness to develop into major disturbances with the result that disruption starts before the formation of the main break-up region. In the two-dimensional variable geometry air-blast atomizer, it is shown that the air flow is responsible for the formation of large, ordered, and small chaotic 'cell' structures.

  18. Safety advice sheets

    CERN Multimedia

    HSE Unit

    2013-01-01

    You never know when you might be faced with questions such as: when/how should I dispose of a gas canister? Where can I find an inspection report? How should I handle/store/dispose of a chemical substance…?   The SI section of the DGS/SEE Group is primarily responsible for safety inspections, evaluating the safety conditions of equipment items, premises and facilities. On top of this core task, it also regularly issues “Safety Advice Sheets” on various topics, designed to be of assistance to users but also to recall and reinforce safety rules and procedures. These clear and concise sheets, complete with illustrations, are easy to display in the appropriate areas. The following safety advice sheets have been issued so far: Other sheets will be published shortly. Suggestions are welcome and should be sent to the SI section of the DGS/SEE Group. Please send enquiries to general-safety-visits.service@cern.ch.

  19. Core/Shell Conjugated Polymer/Quantum Dot Composite Nanofibers through Orthogonal Non-Covalent Interactions

    Directory of Open Access Journals (Sweden)

    Brad W. Watson

    2016-11-01

    Full Text Available Nanostructuring organic polymers and organic/inorganic hybrid materials and controlling blend morphologies at the molecular level are the prerequisites for modern electronic devices including biological sensors, light emitting diodes, memory devices and solar cells. To achieve all-around high performance, multiple organic and inorganic entities, each designed for specific functions, are commonly incorporated into a single device. Accurate arrangement of these components is a crucial goal in order to achieve the overall synergistic effects. We describe here a facile methodology of nanostructuring conjugated polymers and inorganic quantum dots into well-ordered core/shell composite nanofibers through cooperation of several orthogonal non-covalent interactions including conjugated polymer crystallization, block copolymer self-assembly and coordination interactions. Our methods provide precise control on the spatial arrangements among the various building blocks that are otherwise incompatible with one another, and should find applications in modern organic electronic devices such as solar cells.

  20. A super hydrophilic modification of poly(vinylidene fluoride) (PVDF) nanofibers: By in situ hydrothermal approach

    Science.gov (United States)

    Sheikh, Faheem A.; Zargar, Mohammad Afzal; Tamboli, Ashif H.; Kim, Hern

    2016-11-01

    Nanofibers fabricated from Poly(vinylidene fluoride) (PVDF) possesses potential applications in the field of filtrations, because of their excellent resistance towards harsh chemicals. However, the hydrophobicity restricts its further application. In this work, we focus on optimal parameters for post-electrospun tethering of Poly(vinyl alcohol) (PVA) as superhydrophilic domain onto each individual PVDF nanofibers by exploiting the in situ hydrothermal approach. The results indicated an increase in nanofiber diameters due to coating of PVA and improved surface wettability of PVDF nanofibers. The tensile tests of nanofibers indicated that mechanical properties of PVDF nanofibers could be sharply tuned from rigid to ductile. Furthermore, the studies strongly suggest that in situ hydrothermal treatment of post-electrospun nanofibers can improve the water contact angle and these nanofibers can be used in varied applications (e.g., in water purification systems).

  1. Ammonia Sensing Behaviors of TiO2-PANI/PA6 Composite Nanofibers

    Directory of Open Access Journals (Sweden)

    Fenglin Huang

    2012-12-01

    Full Text Available Titanium dioxide-polyaniline/polyamide 6 (TiO2-PANI/PA6 composite nanofibers were prepared by in situ polymerization of aniline in the presence of PA6 nanofibers and a sputtering-deposition process with a high purity titanium sputtering target. TiO2-PANI/PA6 composite nanofibers and PANI/PA6 composite nanofibers were fabricated for ammonia gas sensing. The ammonia sensing behaviors of the sensors were examined at room temperature. All the results indicated that the ammonia sensing property of TiO2-PANI/PA6 composite nanofibers was superior to that of PANI/PA6 composite nanofibers. TiO2-PANI/PA6 composite nanofibers had good selectivity to ammonia. It was also found that the content of TiO2 had a great influence on both the morphology and the sensing property of TiO2-PANI/PA6 composite nanofibers.

  2. Ice Sheets & Ice Cores

    DEFF Research Database (Denmark)

    Mikkelsen, Troels Bøgeholm

    Since the discovery of the Ice Ages it has been evident that Earth’s climate is liable to undergo dramatic changes. The previous climatic period known as the Last Glacial saw large oscillations in the extent of ice sheets covering the Northern hemisphere. Understanding these oscillations known....... The first part concerns time series analysis of ice core data obtained from the Greenland Ice Sheet. We analyze parts of the time series where DO-events occur using the so-called transfer operator and compare the results with time series from a simple model capable of switching by either undergoing...

  3. Energy information sheets

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-02

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the general public. Written for the general public, the EIA publication Energy Information Sheets was developed to provide information on various aspects of fuel production, prices, consumption and capability. The information contained herein pertains to energy data as of December 1991. Additional information on related subject matter can be found in other EIA publications as referenced at the end of each sheet.

  4. In Situ Generation of Cellulose Nanocrystals in Polycaprolactone Nanofibers: Effects on Crystallinity, Mechanical Strength, Biocompatibility, and Biomimetic Mineralization.

    Science.gov (United States)

    Joshi, Mahesh Kumar; Tiwari, Arjun Prasad; Pant, Hem Raj; Shrestha, Bishnu Kumar; Kim, Han Joo; Park, Chan Hee; Kim, Cheol Sang

    2015-09-09

    Post-electrospinning treatment is a facile process to improve the properties of electrospun nanofibers for various applications. This technique is commonly used when direct electrospinning is not a suitable option to fabricate a nonwoven membrane of the desired polymer in a preferred morphology. In this study, a representative natural-synthetic hybrid of cellulose acetate (CA) and polycaprolactone (PCL) in different ratios was fabricated using an electrospinning process, and CA in the hybrid fiber was transformed into cellulose (CL) by post-electrospinning treatment via alkaline saponification. Scanning electron microscopy was employed to study the effects of polymer composition and subsequent saponification on the morphology of the nanofibers. Increasing the PCL content in the PCL/CA blend solution caused a gradual decrease in viscosity, resulting in smoother and more uniform fibers. The saponification of fibers lead to pronounced changes in the physicochemical properties. The crystallinity of the PCL in the composite fiber was varied according to the composition of the component polymers. The water contact angle was considerably decreased (from 124° to less than 20°), and the mechanical properties were greatly enhanced (Young's Modulus was improved by ≈20-30 fold, tensile strength by 3-4 fold, and tensile stress by ≈2-4 fold) compared to those of PCL and PCL/CA membranes. Regeneration of cellulose chains in the nanofibers increased the number of hydroxyl groups, which increased the hydrogen bonding, thereby improving the mechanical properties and wettability of the composite nanofibers. The improved wettability and presence of surface functional groups enhanced the ability to nucleate bioactive calcium phosphate crystals throughout the matrix when exposed to a simulated body fluid solution. Experimental results of cell viability assay, confocal microscopy, and scanning electron microscopy imaging showed that the fabricated nanofibrous membranes have

  5. Dye-sensitized solar cells based on anatase TiO2/multi-walled carbon nanotubes composite nanofibers photoanode

    International Nuclear Information System (INIS)

    Du, Pingfan; Song, Lixin; Xiong, Jie; Li, Ni; Wang, Lijun; Xi, Zhenqiang; Wang, Naiyan; Gao, Linhui; Zhu, Hongliang

    2013-01-01

    Highlights: ► TiO 2 /multi-walled carbon nanotubes (MWCNTs) hybrid nanofibers are prepared via electrospinning. ► Dye-sensitized solar cells (DSSCs) are assembled using TiO 2 /MWCNTs nanofibers film as photoanode. ► Energy conversion efficiency of DSSCs is greatly dependent on the content of MWCNTs. ► Moderate MWCNTs incorporation can substantially enhance the performance of DSSCs. - Abstract: Anatase TiO 2 /multi-walled carbon nanotubes (TiO 2 /MWCNTs) hybrid nanofibers (NFs) film was prepared via a facile electrospinning method. Dye-sensitized solar cells (DSSCs) based on TiO 2 /MWCNTs composite NFs photoanodes with different contents of MWCNTs (0, 0.1, 0.3, 0.5, 1 wt.%) were assembled using N719 dye as sensitizer. Field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), and Raman spectrometer were used to characterize the TiO 2 /MWCNTs electrode films. The photocurrent–voltage (I–V) characteristic, incident photo-to-current conversion efficiency (IPCE) spectrum, and electrochemical impedance spectroscopy (EIS) measurements were carried out to evaluate the photoelectric properties of the DSSCs. The results reveal that the energy conversion efficiency is greatly dependent on the content of MWCNTs in the composite NFs film, and a moderate incorporation of MWCNTs can substantially enhance the performance of DSSCs. When the electrode contains 0.3 wt.% MWCNTs, the corresponding solar cell yield the highest efficiency of 5.63%. This efficiency value is approximately 26% larger than that of the unmodified counterpart.

  6. Branched carbon nanofiber network synthesis at room temperature using radio frequency supported microwave plasmas

    OpenAIRE

    Boskovic, BO; Stolojan, V; Zeze, DA; Forrest, RD; Silva, SRP; Haq, S

    2004-01-01

    Carbon nanofibers have been grown at room temperature using a combination of radio frequency and microwave assisted plasma-enhanced chemical vapor deposition. The nanofibers were grown, using Ni powder catalyst, onto substrates kept at room temperature by using a purposely designed water-cooled sample holder. Branched carbon nanofiber growth was obtained without using a template resulting in interconnected carbon nanofiber network formation on substrates held at room temperatur...

  7. Carbon nanofiber supercapacitors with large areal capacitances

    KAUST Repository

    McDonough, James R.

    2009-01-01

    We develop supercapacitor (SC) devices with large per-area capacitances by utilizing three-dimensional (3D) porous substrates. Carbon nanofibers (CNFs) functioning as active SC electrodes are grown on 3D nickel foam. The 3D porous substrates facilitate a mass loading of active electrodes and per-area capacitance as large as 60 mg/ cm2 and 1.2 F/ cm2, respectively. We optimize SC performance by developing an annealing-free CNF growth process that minimizes undesirable nickel carbide formation. Superior per-area capacitances described here suggest that 3D porous substrates are useful in various energy storage devices in which per-area performance is critical. © 2009 American Institute of Physics.

  8. Collisionless current sheet equilibria

    Science.gov (United States)

    Neukirch, T.; Wilson, F.; Allanson, O.

    2018-01-01

    Current sheets are important for the structure and dynamics of many plasma systems. In space and astrophysical plasmas they play a crucial role in activity processes, for example by facilitating the release of magnetic energy via processes such as magnetic reconnection. In this contribution we will focus on collisionless plasma systems. A sensible first step in any investigation of physical processes involving current sheets is to find appropriate equilibrium solutions. The theory of collisionless plasma equilibria is well established, but over the past few years there has been a renewed interest in finding equilibrium distribution functions for collisionless current sheets with particular properties, for example for cases where the current density is parallel to the magnetic field (force-free current sheets). This interest is due to a combination of scientific curiosity and potential applications to space and astrophysical plasmas. In this paper we will give an overview of some of the recent developments, discuss their potential applications and address a number of open questions.

  9. Cholera Fact Sheet

    Science.gov (United States)

    ... news-room/fact-sheets/detail/cholera","@context":"http://schema.org","@type":"Article"}; العربية 中文 français русский español ... that includes feedback at the local level and information-sharing at the global level. Cholera cases are ...

  10. Pseudomonas - Fact Sheet

    OpenAIRE

    Public Health Agency

    2012-01-01

    Fact sheet on Pseudomonas, including:What is Pseudomonas?What infections does it cause?Who is susceptible to pseudomonas infection?How will I know if I have pseudomonas infection?How can Pseudomonas be prevented from spreading?How can I protect myself from Pseudomonas?How is Pseudomonas infection treated?

  11. NTPR Fact Sheets

    Science.gov (United States)

    History Documents US Underground Nuclear Test History Reports NTPR Radiation Exposure Reports Enewetak Atoll Cleanup Documents TRAC About Who We Are Our Values History Locations Our Leadership Director Support Center Contact Us FAQ Sheet Links Success Stories Contracts Business Opportunities Current

  12. Production (information sheets)

    NARCIS (Netherlands)

    2007-01-01

    Documentation sheets: Geo energy 2 Integrated System Approach Petroleum Production (ISAPP) The value of smartness 4 Reservoir permeability estimation from production data 6 Coupled modeling for reservoir application 8 Toward an integrated near-wellbore model 10 TNO conceptual framework for "E&P

  13. Hibernia fact sheet

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    This fact sheet gives details of the Hibernia oil field including its location, discovery date, oil company's interests in the project, the recoverable reserves of the two reservoirs, the production system used, capital costs of the project, and overall targets for Canadian benefit. Significant dates for the Hibernia project are listed. (UK)

  14. Ethanol Basics (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2015-01-01

    Ethanol is a widely-used, domestically-produced renewable fuel made from corn and other plant materials. More than 96% of gasoline sold in the United States contains ethanol. Learn more about this alternative fuel in the Ethanol Basics Fact Sheet, produced by the U.S. Department of Energy's Clean Cities program.

  15. Growth and characterization of hydroxyapatite nanorice on TiO2 nanofibers

    KAUST Repository

    Chetibi, Loubna; Hamana, Djamel; Achour, Slimane

    2014-01-01

    with anatase TiO2 nanofibers. These nanofibers were prepared by in situ oxidation of Ti foils in a concentrated solution of H 2O2 and NaOH, followed by proton exchange and calcinations. Afterward, TiO2 nanofibers on Ti substrate were coated with HA

  16. Coaxial nanofibers containing TiO2 in the shell for water treatment applications

    Science.gov (United States)

    Kizildag, N.; Geltmeyer, J.; Ucar, N.; De Buysser, K.; De Clerck, K.

    2017-10-01

    In recent years, the basic electrospinning setup has undergone many modifications carried out to enhance the quality and improve the functionality of the resulting nanofibers. Being one of these modifications, coaxial electrospinning has attracted great attention. It enables to use different materials in nanofiber production and produce multi-layered and functional nanofibers in one step. In this study, TiO2 has been added to the shell layer of coaxial nanofibers to develop functional nanofibers which may be used in water treatment applications. The coaxial nanofibers containing TiO2 in the shell layer are compared to uniaxial nanofibers containing TiO2 in bulk fiber structure, regarding their morphology and photocatalytic activity. Uniform uniaxial and coaxial nanofibers with TiO2 were obtained. The average nanofiber diameter of coaxial nanofibers were higher. Coaxial nanofibers, which contained lower amount of TiO2, displayed similar performance to uniaxial nanofibers with TiO2 in terms of photocatalytic degradation ability against isoproturon.

  17. Antioxidant activity and haemolysis prevention efficiency of polyaniline nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Somik; Kumar, A [Materials Research Laboratory, Department of Physics, Tezpur University, Tezpur 784028, Assam (India); Saikia, Jyoti P; Konwar, B K, E-mail: ask@tezu.ernet.in [Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam (India)

    2010-01-29

    Polyaniline (PAni) nanofibers have been synthesized by interfacial polymerization using hydrochloric acid (HCl) and camphor sulfonic acid (CSA) as dopants. The powder x-ray diffraction pattern of bulk polyaniline reveals ES I structure and has been indexed in a pseudo-orthorhombic lattice. The broadening of (110) reflection in the nanofiber samples has been analysed in terms of domain length and strain using a convolution method employing a Voigt function. The increase in d spacing for the (110) reflection in HCl-doped PAni nanofibers have been assigned to the change in structural conformation due to the increase in the tilt angle of the polymer chain, which is also evident from microRaman spectra. UV-vis spectra of the PAni nanofibers exhibit a remarkable blueshift in the absorption bands attributed to {pi}-{pi}{sup *} and {pi}-polaron band transitions indicating a reduction in particle size, which is also observed in TEM micrographs. The antioxidant activity of the polyaniline nanofiber samples has been investigated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay by employing UV-visible spectroscopy. It has also been observed that polyaniline nanofibers are able to protect the haemolysis of red blood cells (RBCs) from cytotoxic agents, namely H{sub 2}O{sub 2}. The observed enhancement in the antioxidant and haemolysis prevention activity of the PAni nanofibers as compared to bulk has been attributed to the reduction in particle size and changes in structural conformation, as evident from TEM, XRD and microRaman spectroscopy.

  18. Rubella - Fact Sheet for Parents

    Science.gov (United States)

    ... and 4 through 6 years Fact Sheet for Parents Color [2 pages] Español: Rubéola The best way ... according to the recommended schedule. Fact Sheets for Parents Diseases and the Vaccines that Prevent Them Chickenpox ...

  19. Improved sensitivity of wearable nanogenerators made of electrospun Eu3+ doped P(VDF-HFP)/graphene composite nanofibers for self-powered voice recognition

    Science.gov (United States)

    Adhikary, Prakriti; Biswas, Anirban; Mandal, Dipankar

    2016-12-01

    Composite nanofibers of Eu3+ doped poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP))/graphene are prepared by the electrospinning technique for the fabrication of ultrasensitive wearable piezoelectric nanogenerators (WPNGs) where the post-poling technique is not necessary. It is found that the complete conversion of the piezoelectric β-phase and the improvement of the degree of crystallinity is governed by the incorporation of Eu3+ and graphene sheets into P(VDF-HFP) nanofibers. The flexible nanocomposite fibers are associated with a hypersensitive electronic transition that results in an intense red light emission, and WPNGs also have the capability of detecting external pressure as low as ~23 Pa with a higher degree of acoustic sensitivity, ~11 V Pa-1, than has ever been previously reported. This means that ultrasensitive WPNGs can be utilized to recognize human voices, which suggests they could be a potential tool in the biomedical and national security sectors. The capacitor’s ability to charge from abundant environmental vibrations, such as music, wind, body motion, etc, drives WPNGs as a power source for portable electronics. This fact may open up the prospect of using the Eu3+ doped P(VDF-HFP)/graphene composite electrospun nanofibers, with their multifunctional properties such as vibration sensitivity, wearability, red light emission capability and piezoelectric energy harvesting, for various promising applications in portable electronics, health care monitoring, noise detection and security monitoring.

  20. Virgin olive oil blended polyurethane micro/nanofibers ornamented with copper oxide nanocrystals for biomedical applications

    Directory of Open Access Journals (Sweden)

    Amna T

    2014-02-01

    Full Text Available Touseef Amna,1 M Shamshi Hassan,2 Jieun Yang,1 Myung-Seob Khil,2 Ki-Duk Song,3 Jae-Don Oh,3 Inho Hwang1 1Department of Animal Sciences and Biotechnology, 2Department of Organic Materials and Fiber Engineering, Chonbuk National University, Jeonju, South Korea; 3Genomic Informatics Center, Hankyong National University, Anseong, South Korea Abstract: Recently, substantial interest has been generated in using electrospun biomimetic nanofibers of hybrids, particularly organic/inorganic, to engineer different tissues. The present work, for the first time, introduced a unique natural and synthetic hybrid micronanofiber wound dressing, composed of virgin olive oil/copper oxide nanocrystals and polyurethane (PU, developed via facile electrospinning. The as-spun organic/inorganic hybrid micronanofibers were characterized by scanning electron microscopy (SEM, energy dispersive X-ray analysis, X-ray diffraction, electron probe microanalysis, and transmission electron microscopy. The interaction of cells with scaffold was studied by culturing NIH 3T3 fibroblasts on an as-spun hybrid micronanofibrous mat, and viability, proliferation, and growth were assessed. The 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay results and SEM observation showed that the hybrid micronanofibrous scaffold was noncytotoxic to fibroblast cell culture and was found to benefit cell attachment and proliferation. Hence our results suggest the potential utilization of as-spun micronanoscaffolds for tissue engineering. Copper oxide–olive oil/PU wound dressing may exert its positive beneficial effects at every stage during wound-healing progression, and these micronanofibers may serve diverse biomedical applications, such as tissue regeneration, damaged skin treatment, wound healing applications, etc. Conclusively, the fabricated olive oil–copper oxide/PU micronanofibers combine the benefits of virgin olive oil and copper oxide, and therefore hold great promise for

  1. Preparation and characterization of single-crystal multiferroic nanofiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Zhaohui; Xiao, Zhen; Yin, Simin; Mai, Jiangquan; Liu, Zhenya; Xu, Gang; Li, Xiang; Shen, Ge [State Key Lab of Silicon Materials, Department of Material Science and Engineering, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); Han, Gaorong, E-mail: hgr@zju.edu.cn [State Key Lab of Silicon Materials, Department of Material Science and Engineering, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China)

    2013-03-05

    Graphical abstract: One-dimensional single-crystal multiferroic composites composed of PbTiO{sub 3} nanofiber-CoFe{sub 2}O{sub 4} nanodot have been prepared for the first time by a facile in situ solid state sintering method. The composites demonstrate ferroelectricity and ferromagnetism as well as strong coupling between them. Highlights: ► 1D single-crystal multiferroic PTO-CFO was prepared via in situ solid state sintering method. ► A simple epitaxial growth relation has been found between the PTO–CFO composites. ► The composites reveal ferroelectricity and ferromagnetism as well as coupling between them. -- Abstract: One-dimensional single-crystal multiferroic composites consisting of PbTiO{sub 3} (PTO) nanofiber-CoFe{sub 2}O{sub 4} (CFO) nanodot were prepared using an in situ solid state sintering method, where pre-perovskite PTO nanofibers and CFO nanodots were used as precursors. Structural analyses by using transmission electron microscopy, scanning electron microscopy and X-ray diffraction determined a epitaxial growth relation between the PTO nanofiber and the CFO nanodot. Ferromagnetism and ferroelectricity of the nanofiber composites were investigated by using vibarting sample magnetometer (VSM) and piezoresponse force microscopy (PFM)

  2. Modeling, simulation, and experiments of coating growth on nanofibers

    International Nuclear Information System (INIS)

    Clemons, C. B.; Hamrick, P.; Heminger, J.; Kreider, K. L.; Young, G. W.; Buldum, A.; Evans, E.; Zhang, G.

    2008-01-01

    This work is a comparison of modeling and simulation results with experiments for an integrated experimental/modeling investigation of a procedure to coat nanofibers and core-clad nanostructures with thin film materials using plasma enhanced physical vapor deposition. In the experimental effort, electrospun polymer nanofibers are coated with metallic materials under different operating conditions to observe changes in the coating morphology. The modeling effort focuses on linking simple models at the reactor level, nanofiber level and atomic level to form a comprehensive model. The comprehensive model leads to the definition of an evolution equation for the coating free surface around an isolated nanofiber. This evolution equation was previously derived and solved under conditions of a nearly circular coating, with a concentration field that was only radially dependent and that was independent of the location of the coating free surface. These assumptions permitted the development of analytical expressions for the concentration field. The present work does not impose the above-mentioned conditions and considers numerical simulations of the concentration field that couple with level set simulations of the evolution equation for the coating free surface. Further, the cases of coating an isolated fiber as well as a multiple fiber mat are considered. Simulation results are compared with experimental results as the reactor pressure and power, as well as the nanofiber mat porosity, are varied

  3. Enhancement of Ultrahigh Performance Concrete Material Properties with Carbon Nanofiber

    Directory of Open Access Journals (Sweden)

    Libya Ahmed Sbia

    2014-01-01

    Full Text Available Ultrahigh performance concrete (UHPC realized distinctly high mechanical, impermeability, and durability characteristics by reducing the size and content of capillary pore, refining the microstructure of cement hydrates, and effectively using fiber reinforcement. The dense and fine microstructure of UHPC favor its potential to effectively disperse and interact with nanomaterials, which could complement the reinforcing action of fibers in UHPC. An optimization experimental program was implemented in order to identify the optimum combination of steel fiber and relatively low-cost carbon nanofiber in UHPC. The optimum volume fractions of steel fiber and carbon nanofiber identified for balanced improvement of flexural strength, ductility, energy sorption capacity, impact, and abrasion resistance of UHPC were 1.1% and 0.04%, respectively. Desired complementary/synergistic actions of nanofibers and steel fibers in UHPC were detected, which were attributed to their reinforcing effects at different scales, and the potential benefits of nanofibers to interfacial bonding and pull-out behavior of fibers in UHPC. Modification techniques which enhanced the hydrophilicity and bonding potential of nanofibers to cement hydrates benefited their reinforcement efficiency in UHPC.

  4. Dry adhesives from carbon nanofibers grown in an open ethanol flame

    Directory of Open Access Journals (Sweden)

    Christian Lutz

    2017-12-01

    Full Text Available Based on magnetic-field-assisted growth of carbon nanofibers in an open ethanol flame we fabricated arrays of carbon nanofibers with different degrees of orientation. Inspired by the dry adhesive system of geckos we investigated the adhesive properties of such carbon nanofiber arrays with ordered and random orientation. AFM-based force spectroscopy revealed that adhesion force and energy rise linear with preload force. Carbon nanofibers oriented by a magnetic field show a 68% higher adhesion (0.66 N/cm2 than the randomly oriented fibers. Endurance tests revealed that the carbon nanofiber arrays withstand 50.000 attachment/detachment cycles without observable wear.

  5. Film sheet cassette

    International Nuclear Information System (INIS)

    1981-01-01

    A novel film sheet cassette is described for handling CAT photographic films under daylight conditions and facilitating their imaging. A detailed description of the design and operation of the cassette is given together with appropriate illustrations. The resulting cassette is a low-cost unit which is easily constructed and yet provides a sure light-tight seal for the interior contents of the cassette. The individual resilient fingers on the light-trap permit the ready removal of the slide plate for taking pictures. The stippled, non-electrostatic surface of the pressure plate ensures an air layer and free slidability of the film for removal and withdrawal of the film sheet. The advantage of the daylight system is that a darkroom need not be used for inserting and removing the film in and out of the cassette resulting in a considerable time saving. (U.K.)

  6. Clean Cities Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    2004-01-01

    This fact sheet explains the Clean Cities Program and provides contact information for all coalitions and regional offices. It answers key questions such as: What is the Clean Cities Program? What are alternative fuels? How does the Clean Cities Program work? What sort of assistance does Clean Cities offer? What has Clean Cities accomplished? What is Clean Cities International? and Where can I find more information?

  7. Information sheets on energy

    International Nuclear Information System (INIS)

    2004-01-01

    These sheets, presented by the Cea, bring some information, in the energy domain, on the following topics: the world energy demand and the energy policy in France and in Europe, the part of the nuclear power in the energy of the future, the greenhouse gases emissions and the fight against the greenhouse effect, the carbon dioxide storage cost and the hydrogen economy. (A.L.B.)

  8. Biomolecular Science (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-04-01

    A brief fact sheet about NREL Photobiology and Biomolecular Science. The research goal of NREL's Biomolecular Science is to enable cost-competitive advanced lignocellulosic biofuels production by understanding the science critical for overcoming biomass recalcitrance and developing new product and product intermediate pathways. NREL's Photobiology focuses on understanding the capture of solar energy in photosynthetic systems and its use in converting carbon dioxide and water directly into hydrogen and advanced biofuels.

  9. 3D carbon fiber mats/nano-Fe3O4 hybrid material with high electromagnetic shielding performance

    Science.gov (United States)

    Zhan, Yingqing; Long, Zhihang; Wan, Xinyi; Zhang, Jiemin; He, Shuangjiang; He, Yi

    2018-06-01

    To obtain high-performance electromagnetic shielding materials, structure and morphology are two key factors. We here developed an efficient and facial method to prepare high-performance 3D carbon nanofiber mats (CFM)/Fe3O4 hybrid electromagnetic shielding materials. For this purpose, the CFM were chemically modified by mussel-inspired poly-dopamine coating, which were further used as templates for decoration of Fe3O4 nanoparticles via solvothermal route. It was found that the Fe3O4 nano-spheres with diameters of 200-250 nm were uniformly coated on the surface of 3D carbon nanofibers. More importantly, the morphology and structure of resulting 3D carbon nanofiber mats/Fe3O4 hybrids could be easily controlled by altering the experiment parameters, which were examined by FT-IR, XPS, TGA, XRD, SEM, and TEM. The measured magnetic properties showed that saturation magnetism and coercivity increased from 13.4 to 39.7 emu/g and 85.3 to 104.6 Oe, respectively. The lowest reflectivity of resulting hybrid was calculated to be -47 dB at 10.0 GHz (2.5 mm). In addition, the reflectivity of 3D carbon nanofiber mats/Fe3O4 hybrid was less than -25 dB in the range of 7-13 GHz. Moreover, the resulting 3D carbon nanofiber mats/Fe3O4 hybrid exhibited an EMI shielding performance of -62.6 dB in the frequency range of 8.2-12.4 GHz. Therefore, 3D carbon fiber mats/Fe3O4 hybrids can be ideal EMI materials with strong absorption, low density, and wide absorption range.

  10. Sheet pinch devices

    International Nuclear Information System (INIS)

    Anderson, O.A.; Baker, W.R.; Ise, J. Jr.; Kunkel, W.B.; Pyle, R.V.; Stone, J.M.

    1958-01-01

    Three types of sheet-like discharges are being studied at Berkeley. The first of these, which has been given the name 'Triax', consists of a cylindrical plasma sleeve contained between two coaxial conducting cylinders A theoretical analysis of the stability of the cylindrical sheet plasma predicts the existence of a 'sausage-mode' instability which is, however, expected to grow more slowly than in the case of the unstabilized linear pinch (by the ratio of the radial dimensions). The second pinch device employs a disk shaped discharge with radial current guided between flat metal plates, this configuration being identical to that of the flat hydromagnetic capacitor without external magnetic field. A significant feature of these configurations is the absence of a plasma edge, i.e., there are no regions of sharply curved magnetic field lines anywhere in these discharges. The importance of this fact for stability is not yet fully investigated theoretically. As a third configuration a rectangular, flat pinch tube has been constructed, and the behaviour of a flat plasma sheet with edges is being studied experimentally

  11. Evaluation of proanthocyanidin-crosslinked electrospun gelatin nanofibers for drug delivering system

    International Nuclear Information System (INIS)

    Huang, Chiung-Hua; Chi, Chin-Ying; Chen, Yueh-Sheng; Chen, Kuo-Yu; Chen, Pei-Lain; Yao, Chun-Hsu

    2012-01-01

    Electrospun nanofibers are excellent candidates for various biomedical applications. We successfully fabricated proanthocyanidin‐crosslinked gelatin electrospun nanofibers. Proanthocyanidin, a low cytotoxic collagen crosslinking reagent, increased the gelatin crosslinking percentage in the nanofibers from 53% to 64%. The addition of proanthocyanidin kept the nanofibers from swelling, and, thus, made the fibers more stable in the aqueous state. The compatibility and the release behavior of the drug in the nanofibers were examined using magnesium ascorbyl phosphate as the model drug. Proanthocyanidin also promoted drug loading and kept the drug release rate constant. These properties make the proanthocyanidin‐crosslinked gelatin nanofibers an excellent material for drug delivery. In the cell culture study, L929 fibroblast cells had a significantly higher proliferation rate when cultured with the gelatin/proanthocyanidin blended nanofibers. This characteristic showed that proanthocyanidin‐crosslinked gelatin electrospun nanofibers could potentially be employed as a wound healing material by increasing cell spreading and proliferation. - Highlights: ► Proanthocyanidin‐crosslinked gelatin nanofibers (GEL/PA) is synthesized. ► Proanthocyanidin promoted drug loading and kept the drug release rate constant. ► The GEL/PA nanofibers accelerate fibroblast cell proliferation. ► The GEL/PA nanofibers increase the drug loading efficiency.

  12. Bioactive Glass Nanoparticles-Loaded Poly(ɛ-caprolactone Nanofiber as Substrate for ARPE-19 Cells

    Directory of Open Access Journals (Sweden)

    Tadeu Henrique Lima

    2016-01-01

    Full Text Available Bioactive glass nanoparticles-loaded poly(ɛ-caprolactone nanofibers (BIOG PCL nanofibers were synthesized and evaluated as substrates for ocular cells (ARPE-19. BIOG PCL nanofibers were characterized using SEM, FTIR, and DSC, and the in vitro degradation profile was also investigated. The in vitro ocular biocompatibility of nanofibers was exploited in Müller glial cells (MIO-M1 cells and in chorioallantoic membrane (CAM; and the proliferative capacity, cytotoxicity, and functionality were evaluated. Finally, ARPE-19 cells were seeded onto BIOG PCL nanofibers and they were investigated as supports for in vitro cell adhesion and proliferation. SEM images revealed the incorporation of BIOG nanoparticles into PCL nanofibers. Nanoparticles did not induce modifications in the chemical structure and semicrystalline nature of PCL in the nanofiber, as shown by FTIR and DSC. MIO-M1 cells exposed to BIOG PCL nanofibers showed viability, and they were able to proliferate and to express GFAP, indicating cellular functionality. Moreover, nanofibers were well tolerated by CAM. These findings suggested the in vitro ocular biocompatibility and absence of toxicity of these nanofibers. Finally, the BIOG nanoparticles modulated the protein adsorption, and, subsequently, ARPE-19 cells adhered and proliferated onto the nanostructured supports, establishing cell-substrate interactions. In conclusion, the biodegradable and biocompatible BIOG PCL nanofibers supported the ARPE-19 cells.

  13. Improving effects of chitosan nanofiber scaffolds on osteoblast proliferation and maturation

    Science.gov (United States)

    Ho, Ming-Hua; Liao, Mei-Hsiu; Lin, Yi-Ling; Lai, Chien-Hao; Lin, Pei-I; Chen, Ruei-Ming

    2014-01-01

    Osteoblast maturation plays a key role in regulating osteogenesis. Electrospun nanofibrous products were reported to possess a high surface area and porosity. In this study, we developed chitosan nanofibers and examined the effects of nanofibrous scaffolds on osteoblast maturation and the possible mechanisms. Macro- and micro observations of the chitosan nanofibers revealed that these nanoproducts had a flat surface and well-distributed fibers with nanoscale diameters. Mouse osteoblasts were able to attach onto the chitosan nanofiber scaffolds, and the scaffolds degraded in a time-dependent manner. Analysis by scanning electron microscopy further showed mouse osteoblasts adhered onto the scaffolds along the nanofibers, and cell–cell communication was also detected. Mouse osteoblasts grew much better on chitosan nanofiber scaffolds than on chitosan films. In addition, human osteoblasts were able to adhere and grow on the chitosan nanofiber scaffolds. Interestingly, culturing human osteoblasts on chitosan nanofiber scaffolds time-dependently increased DNA replication and cell proliferation. In parallel, administration of human osteoblasts onto chitosan nanofibers significantly induced osteopontin, osteocalcin, and alkaline phosphatase (ALP) messenger (m)RNA expression. As to the mechanism, chitosan nanofibers triggered runt-related transcription factor 2 mRNA and protein syntheses. Consequently, results of ALP-, alizarin red-, and von Kossa-staining analyses showed that chitosan nanofibers improved osteoblast mineralization. Taken together, results of this study demonstrate that chitosan nanofibers can stimulate osteoblast proliferation and maturation via runt-related transcription factor 2-mediated regulation of osteoblast-associated osteopontin, osteocalcin, and ALP gene expression. PMID:25246786

  14. Surface functionalization of carbon nanofibers by sol-gel coating of zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Shao Dongfeng [Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi 214122 (China); Changzhou Textile Garment Institute, Changzhou 213164 (China); Wei Qufu [Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi 214122 (China)], E-mail: qfwei@jiangnan.edu.cn; Zhang Liwei; Cai Yibing; Jiang Shudong [Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi 214122 (China)

    2008-08-15

    In this paper the functional carbon nanofibers were prepared by the carbonization of ZnO coated PAN nanofibers to expand the potential applications of carbon nanofibers. Polyacrylonitrile (PAN) nanofibers were obtained by electrospinning. The electrospun PAN nanofibers were then used as substrates for depositing the functional layer of zinc oxide (ZnO) on the PAN nanofiber surfaces by sol-gel technique. The effects of coating, pre-oxidation and carbonization on the surface morphology and structures of the nanofibers were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM), respectively. The results of SEM showed a significant increase of the size of ZnO nanograins on the surface of nanofibers after the treatments of coating, pre-oxidation and carbonization. The observations by SEM also revealed that ZnO nanoclusters were firmly and clearly distributed on the surface of the carbon nanofibers. FTIR examination also confirmed the deposition of ZnO on the surface of carbon nanofibers. The XRD analysis indicated that the crystal structure of ZnO nanograins on the surface of carbon nanofibers.

  15. Electrochemical Performance of Electrospun carbon nanofibers as free-standing and binder-free anodes for Sodium-Ion and Lithium-Ion Batteries

    International Nuclear Information System (INIS)

    Jin, Juan; Shi, Zhi-qiang; Wang, Cheng-yang

    2014-01-01

    Highlights: • Electrospun carbon nanofiber webs were prepared by pyrolysis of polyacrylonitrile. • The webs as binder-free and current collector-free electrodes for SIBs and LIBs. • Different layer spacing and pore size for Li and Na lead different electrochemical behavior. • Electrochemical performances of the electrodes were high. - Abstract: A series of hard carbon nanofiber-based electrodes derived from electrospun polyacrylonitrile (PAN) nanofibers (PAN-CNFs) have been fabricated by stabilization in air at about 280 °C and then carbonization in N 2 at heat treatment temperatures (HTT) between 800 and 1500 °C. The electrochemical performances of the binder-free, current collector-free carbon nanofiber-based anodes in lithium-ion batteries and sodium-ion batteries are systematically investigated and compared. We demonstrate the presence of similar alkali metal insertion mechanisms in both cases, but just the differences of the layer spacing and pore size available for lithium and sodium ion lead the discharge capacity delivered at sloping region and plateau region to vary from the kinds of alkali elements. Although the anodes in sodium-ion batteries show poorer rate capability than that in lithium-ion batteries, they still achieve a reversible sodium intercalation capacity of 275 mAh g −1 and similar cycling stability due to the conductive 3-D network, weakly ordered turbostratic structure and a large interlayer spacing between graphene sheets. The feature of high capacity and stable cycling performance makes PAN-CNFs to be promising candidates as electrodes in rechargeable sodium-ion batteries and lithium-ion batteries

  16. Development of green nanocomposites reinforced by cellulose nanofibers extracted from paper sludge

    Science.gov (United States)

    Takagi, Hitoshi; Nakagaito, Antonio N.; Kusaka, Kazuya; Muneta, Yuya

    2015-03-01

    Cellulose nanofibers have been showing much greater potential to enhance the mechanical and physical properties of polymer-based composite materials. The purpose of this study is to extract the cellulose nanofibers from waste bio-resources; such as waste newspaper and paper sludge. The cellulosic raw materials were treated chemically and physically in order to extract individualized cellulose nanofiber. The combination of acid hydrolysis and following mechanical treatment resulted in the extraction of cellulose nanofibers having diameter of about 40 nm. In order to examine the reinforcing effect of the extracted cellulose nanofibers, fully biodegradable green nanocomposites were fabricated by composing polyvinyl alcohol (PVA) resin with the extracted cellulose nanofibers, and then the tensile tests were conducted. The results showed that the enhancement in mechanical properties was successfully obtained in the cellulose nanofiber/PVA green nanocomposites.

  17. Biomedical Applications of Antibacterial Nanofiber Mats Made of Electrospinning with Wire Electrodes

    Directory of Open Access Journals (Sweden)

    Yi-Jun Pan

    2016-02-01

    Full Text Available Twisted stainless steel wires are used as wire electrodes for electrospinning the polyvinyl alcohol (PVA/zinc citrate nanofiber mats. The morphology and diameter of the nanofibers in PVA/zinc citrate nanofiber mats are evaluated. We measured the antibacterial efficacy against Staphylococcus aureus (S. aureus and Escherichia coli (E. coli of the nanofiber mats. We also examined the cell adhesion affinity of mammalian tissue culture cells on these nanofiber mats. Our results indicate that an increase in zinc citrate increases the viscosity and electrical conductivity of PVA solution. In addition, increasing zinc citrate results in a smaller diameter of nanofibers that reaches below 100 nm. According to the antibacterial test results, increasing zinc citrate enlarges the inhibition zone of S. aureus but only has a bacteriostatic effect against E. coli. Finally, cell adhesion test results indicate that all nanofiber mats have satisfactory cell attachment regardless of the content of zinc citrate.

  18. Facile Synthesis of Porous Silicon Nanofibers by Magnesium Reduction for Application in Lithium Ion Batteries.

    Science.gov (United States)

    Cho, Daehwan; Kim, Moonkyoung; Hwang, Jeonghyun; Park, Jay Hoon; Joo, Yong Lak; Jeong, Youngjin

    2015-12-01

    We report a facile fabrication of porous silicon nanofibers by a simple three-stage procedure. Polymer/silicon precursor composite nanofibers are first fabricated by electrospinning, a water-based spinning dope, which undergoes subsequent heat treatment and then reduction using magnesium to be converted into porous silicon nanofibers. The porous silicon nanofibers are coated with a graphene by using a plasma-enhanced chemical vapor deposition for use as an anode material of lithium ion batteries. The porous silicon nanofibers can be mass-produced by a simple and solvent-free method, which uses an environmental-friendly polymer solution. The graphene-coated silicon nanofibers show an improved cycling performance of a capacity retention than the pure silicon nanofibers due to the suppression of the volume change and the increase of electric conductivity by the graphene.

  19. Electrospinning cellulose based nanofibers for sensor applications

    Science.gov (United States)

    Nartker, Steven

    2009-12-01

    Bacterial pathogens have recently become a serious threat to the food and water supply. A biosensor based on an electrochemical immunoassay has been developed for detecting food borne pathogens, such as Escherichia coli (E. coli) O157:H7. These sensors consist of several materials including, cellulose, cellulose nitrate, polyaniline and glass fibers. The current sensors have not been optimized in terms of microscale architecture and materials. The major problem associated with the current sensors is the limited concentration range of pathogens that provides a linear response on the concentration conductivity chart. Electrospinning is a process that can be used to create a patterned fiber mat design that will increase the linear range and lower the detection limit of these sensors by improving the microscale architecture. Using the electrospinning process to produce novel mats of cellulose nitrate will offer improved surface area, and the cellulose nitrate can be treated to further improve chemical interactions required for sensor activity. The macro and micro architecture of the sensor is critical to the performance of the sensors. Electrospinning technology can be used to create patterned architectures of nanofibers that will enhance sensor performance. To date electrospinning of cellulose nitrate has not been performed and optimization of the electrospinning process will provide novel materials suitable for applications such as filtration and sensing. The goal of this research is to identify and elucidate the primary materials and process factors necessary to produce cellulose nitrate nanofibers using the electrospinning process that will improve the performance of biosensors. Cellulose nitrate is readily dissolved in common organic solvents such as acetone, tetrahydrofuran (THF) and N,N dimethylformamide (DMF). These solvents can be mixed with other latent solvents such as ethanol and other alcohols to provide a solvent system with good electrospinning behavior

  20. Nanostructure induced changes in lifetime and enhanced second-harmonic response of organic-plasmonic hybrids

    Energy Technology Data Exchange (ETDEWEB)

    Leißner, Till [NanoSYD, Mads Clausen Institute, University of Southern Denmark, Alsion 2, 6400 Sønderborg (Denmark); Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense (Denmark); Kostiučenko, Oksana; Rubahn, Horst-Günter; Fiutowski, Jacek, E-mail: fiutowski@mci.sdu.dk [NanoSYD, Mads Clausen Institute, University of Southern Denmark, Alsion 2, 6400 Sønderborg (Denmark); Brewer, Jonathan R. [Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense (Denmark)

    2015-12-21

    In this letter we show that the optical response of organic nanofibers, grown from functionalized para-quaterphenylene molecules, can be controlled by forming organic-plasmonic hybrid systems. The interaction between nanofibers and supporting regular arrays of nanostructures leads to a strongly enhanced second harmonic response. At the same time, the fluorescence lifetime of the nanofibers is reduced from 0.32 ns for unstructured gold films to 0.22 ns for gold nanosquare arrays, demonstrating efficient organic–plasmonic interaction. To study the origin of these effects, we applied two-photon laser scanning microscopy and fluorescence lifetime imaging microscopy. These findings provide an effective approach for plasmon-enhanced second-harmonic generation at the nanoscale, which is attractive for nanophotonic circuitry.

  1. Preservation of plasmonic interactions in DLC protected robust organic-plasmonic hybrid systems

    DEFF Research Database (Denmark)

    Cielecki, Pawel Piotr; Sobolewska, Elżbieta Karolina; Kostiučenko, Oksana

    Gold is the most commonly used plasmonic material, however soft and prone to mechanical deformations. It has been previously shown that the durability of gold plasmonic substrates can be improved by applying a protective diamond-like carbon (DLC) coating [1]. In this work, we investigate...... the influence of such protective layers on plasmonic interactions in organic-plasmonic hybrid systems. We consider systems, consisting of 1-Cyano-quaterphenylene nanofibers on top of gold nano-square plasmonic arrays [2], coated with protective layers of varying thickness. We investigate the spectral position...... response of organic nanofibers. Subsequently, we experimentally characterize the plasmonic coupling between organic nanofibers and underlying substrates by time-resolved photoluminescence spectroscopy. Our findings reveal that the optimal thickness for DLC coating, in terms of mechanical protection while...

  2. Conductive Au nanowires regulated by silk fibroin nanofibers

    Science.gov (United States)

    Dong, Bo-Ju; Lu, Qiang

    2014-03-01

    Conductive Au-biopolymer composites have promising applications in tissue engineering such as nerve tissue regeneration. In this study, silk fibroin nanofibers were formed in aqueous solution by regulating silk self-assembly process and then used as template for Au nanowire fabrication. We performed the synthesis of Au seeds by repeating the seeding cycles for several times in order to increase the density of Au seeds on the nanofibers. After electroless plating, densely decorated Au seeds grew into irregularly shaped particles following silk nanofiber to fill the gaps between particles and finally form uniform continuous nanowires. The conductive property of the Au-silk fibroin nanowires was studied with current-voltage ( I-V) measurement. A typical ohmic behavior was observed, which highlighted their potential applications in nerve tissue regeneration.

  3. Pulsed laser dewetting of nickel catalyst for carbon nanofiber growth

    International Nuclear Information System (INIS)

    Guan, Y F; Pearce, R C; Simpson, M L; Rack, P D; Melechko, A V; Hensley, D K

    2008-01-01

    We present a pulsed laser dewetting technique that produces single nickel catalyst particles from lithographically patterned disks for subsequent carbon nanofiber growth through plasma enhanced chemical vapor deposition. Unlike the case for standard heat treated Ni catalyst disks, for which multiple nickel particles and consequently multiple carbon nanofibers (CNFs) are observed, single vertically aligned CNFs could be obtained from the laser dewetted catalyst. Different laser dewetting parameters were tested in this study, such as the laser energy density and the laser processing time measured by the total number of laser pulses. Various nickel disk radii and thicknesses were attempted and the resultant number of carbon nanofibers was found to be a function of the initial disk dimension and the number of laser pulses

  4. Improved infiltration of stem cells on electrospun nanofibers

    International Nuclear Information System (INIS)

    Shabani, Iman; Haddadi-Asl, Vahid; Seyedjafari, Ehsan; Babaeijandaghi, Farshad; Soleimani, Masoud

    2009-01-01

    Nanofibrous scaffolds have been recently used in the field of tissue engineering because of their nano-size structure which promotes cell attachment, function, proliferation and infiltration. In this study, nanofibrous polyethersulfone (PES) scaffolds was prepared via electrospinning. The scaffolds were surface modified by plasma treatment and collagen grafting. The surface changes then investigated by contact angle measurements and FTIR-ATR. The results proved grafting of the collagen on nanofibers surface and increased hydrophilicity after plasma treatment and collagen grafting. The cell interaction study was done using stem cells because of their ability to differentiate to different kinds of cell lines. The cells had normal morphology on nanofibers and showed very high infiltration through collagen grafted PES nanofibers. This infiltration capability is very useful and needed to make 3D scaffolds in tissue engineering.

  5. Uniaxially aligned ceramic nanofibers obtained by chemical mechanical processing

    Energy Technology Data Exchange (ETDEWEB)

    Tararam, R. [Univ Estadual Paulista – UNESP – Instituto de Química, Rua Prof. Francisco Degni n° 55, CEP 14800-900 Araraquara, SP (Brazil); Foschini, C.R. [Univ Estadual Paulista – UNESP – Faculdade de Engenharia de Bauru, Dept. de Eng. Mecanica, Av. Eng. Luiz Edmundo C. Coube 14-01, CEP 17033-360 Bauru, SP (Brazil); Destro, F.B. [Univ Estadual Paulista – UNESP – Faculdade de Engenharia de Guaratinguetá, Guaratinguetá 12516-410, SP (Brazil); Simões, A.Z., E-mail: alezipo@yahoo.com [Univ Estadual Paulista – UNESP – Faculdade de Engenharia de Guaratinguetá, Guaratinguetá 12516-410, SP (Brazil); Longo, E.; Varela, J.A. [Univ Estadual Paulista – UNESP – Instituto de Química, Rua Prof. Francisco Degni n° 55, CEP 14800-900 Araraquara, SP (Brazil)

    2014-08-01

    For this study, we investigated a simple method to generate well aligned nanofibers over large areas using an organic polymer stretched over the substrate surface With this method, ZnO and CuO 3D parallel nanowire arrays were successfully prepared by calcinations of the polymer fibers. X-ray diffraction (XRD) analysis revealed that the copper oxide has a monoclinic structure while the zinc oxide has a hexagonal structure. Scanning electron microscopy (SEM) analysis showed ceramic nanofibers with an average diameter of 120 nm which were composed of small nanoparticles which are 10 nm in diameter. The ability to obtain uniaxially aligned nanofibers reveals a range of interesting properties with potential applications for sensors, catalysts and energy technologies.

  6. Bubble-electrospinning: a novel method for making nanofibers

    International Nuclear Information System (INIS)

    Liu, Y; He, J-H; Yu, J-Y

    2008-01-01

    Nanofibers produced by electrospinning are already being used in a vast array of products in many industries. However, the volume of production of nanofibers has been being a bottleneck restricting their applications. In this work we reported a novel method to fabricate continuous and uniform nanofibers by electrospinning using an aerated polymer solution in an electric field. Multiple jets, which were a prerequisite for increasing the volume of production, were found in this electrospinning process. The morphology of the deposited fibers was straight, coiled and helix observed by a scanning electron microscope (SEM) and an optical microscopy. The results showed that the product of this process was similar to that of a traditional electrospinning process and illustrated a good prospect of application

  7. Modeling and simulation of axisymmetric coating growth on nanofibers

    International Nuclear Information System (INIS)

    Moore, K.; Clemons, C. B.; Kreider, K. L.; Young, G. W.

    2007-01-01

    This work is a modeling and simulation extension of an integrated experimental/modeling investigation of a procedure to coat nanofibers and core-clad nanostructures with thin film materials using plasma enhanced physical vapor deposition. In the experimental effort, electrospun polymer nanofibers are coated with metallic materials under different operating conditions to observe changes in the coating morphology. The modeling effort focuses on linking simple models at the reactor level, nanofiber level, and atomic level to form a comprehensive model. The comprehensive model leads to the definition of an evolution equation for the coating free surface. This equation was previously derived and solved under a single-valued assumption in a polar geometry to determine the coating morphology as a function of operating conditions. The present work considers the axisymmetric geometry and solves the evolution equation without the single-valued assumption and under less restrictive assumptions on the concentration field than the previous work

  8. Functionalized carbon nanotubes and nanofibers for biosensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jun; Lin, Yuehe

    2008-07-30

    This review summarizes the recent advances of carbon nanotube (CNT) and carbon nanofiber (CNF)-based electrochemical biosensors with an emphasis on the applications of CNTs. Carbon nanotubes and carbon nanofibers have unique electric, electrocatalytic, and mechanical properties which make them efficient materials for the use in electrochemical biosensor development. In this article, the functionalization of CNTs for biosensors is simply discussed. The electrochemical biosensors based on CNT and their various applications, e.g., measurement of small biological molecules and environmental pollutants, detection of DNA, and immunosensing of disease biomarkers, are reviewed. Moreover, the development of carbon nanofiber-based electrochemical biosensors and their applications are outlined. Finally, some challenges are discussed in the conclusion.

  9. A "Tandem" Strategy to Fabricate Flexible Graphene/Polypyrrole Nanofiber Film Using the Surfactant-Exfoliated Graphene for Supercapacitors.

    Science.gov (United States)

    Shu, Kewei; Chao, Yunfeng; Chou, Shulei; Wang, Caiyun; Zheng, Tian; Gambhir, Sanjeev; Wallace, Gordon G

    2018-06-19

    The surfactant-assisted liquid-phase exfoliation of expanded graphite can produce graphene sheets in large quantities with minimal defects. However, it is difficult to completely remove the surfactant from the final product, thus affecting the electrochemical properties of the produced graphene. In this article, a novel approach to fabricate flexible graphene/polypyrrole film was developed: using surfactant cetyltrimethylammonium bromide as a template for growth of polypyrrole nanofibers (PPyNFs) instead of removal after the exfoliation process; followed by a simple filtration method. The introduction of PPyNF not only increases the electrochemical performance, but also ensures flexibility. This composite film electrode offers a capacitance up to 161 F g -1 along with a capacitance retention rate of over 80% after 5000 cycles.

  10. Stability of β-carotene in polyethylene oxide electrospun nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Peinado, I., E-mail: irpeipar@upvnet.upv.es [Free University of Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Mason, M.; Romano, A. [Free University of Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Biasioli, F. [Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach (FEM), via E. Mach 1, 38010 San Michele all ‘Adige, TN (Italy); Scampicchio, M., E-mail: matteo.scampicchio@unibz.it [Free University of Bolzano, Piazza Università 5, 39100 Bolzano (Italy)

    2016-05-01

    Highlights: • β-carotene was incorporated into PEO-nanofibers by electrospinning. • Properties of the fibers were analyzed by SEM, color analysis, and DSC. • TGA coupled to PTR–ms resulted promising to online-monitoring thermal degradation. • Thermal stability of βc increased after encapsulation into the PEO-nanofibers. - Abstract: β-carotene (βc) was successfully incorporated into electrospun nanofibers of poly-(ethylene oxide) (PEO) with the aim of prolonging its shelf life and thermal stability. The physical and thermal properties of the βc-PEO-nanofibers were determined by scanning electron microscopy (SEM), color analysis, and differential scanning calorimetry (DSC). The nanofibers of PEO and βc-PEO exhibited average fiber diameters of 320 ± 46 and 230 ± 21 nm, with colorimetric coordinates L* = 95.7 ± 2.4 and 89.4 ± 4.6 and b* = −0.5 ± 0.1 and 6.2 ± 3.0 respectively. Thermogravimetric analysis coupled with Proton Transfer–Mass Spectroscopy (TGA/PTR–ms) demonstrated that coated βc inside PEO nanofibers increased thermal stability when compared to standard βc in powder form. In addition, β-carotene in the membranes showed higher stability during storage when compared with β-carotene in solution with a decrease in concentration of 57 ± 4% and 70 ± 2% respectively, thus should extend the shelf life of this compound. Also, TGA coupled with PTR–MS resulted in a promising technique to online-monitoring thermal degradation.

  11. Polyaniline emeraldine base nanofibers as a radiostabilizing agent for PMMA

    International Nuclear Information System (INIS)

    Araujo, Patricia L.B.; Ferreira, Carlas C.; Araujo, Elmo S.

    2007-01-01

    Polyaniline (PANI) presents antioxidant and radical-scavenging properties. Substances having these characteristics are good candidates for radioprotecting agents. Some studies have also shown results pointing out to biocompatibility and biodegradability of PANI. These characteristics are desirable for substances in contact with biological tissues and have important implications for inclusion of PANI in physical mixtures with conventional radiosterilizable polymers. In this work, nanofibers of polyaniline emeraldine doped with (±)-camphor-10-sulfonic acid (PANI-(±)-CSA) were prepared by self-assembly method. Polyaniline emeraldine base (PANI-EB) nanofibers were obtained after dedoping with NH 4 OH and used as additives in films of commercial poly (methyl methacrylate) (PMMA). In order to assess possible radiostabilizing effects of PANI-EB and its aniline monomer (An) on the PMMA matrix, films containing 0.075 and 0.15% (wt/wt) of these substances were submitted to gamma irradiation from 25 to 75 kGy doses. Variation on viscosity-average molar mass (Mv) of the PMMA matrix at 25 kGy dose showed that samples containing An and PANI-EB nanofibers in amounts of 0.15% (wt/wt) underwent less degradation than control sample. When nanofibers were used as additives, no measurable variation of Mv could be detected in PMMA samples at this dose. At 75 kGy, all composites containing PANI-EB nanofibers underwent less degradation than control samples, suggesting that these additives are able to retain their action at doses higher than standard sterilization dose. These evidences show that PANI-EB nanofibers could be useful additives in commercial PMMA used in medical applications. FTIR spectroscopic characterization and scanning electron microscopy (SEM) of PANI samples were also performed. (author)

  12. Hybrid Magnetic Shielding

    Science.gov (United States)

    Royal, Kevin; Crawford, Christopher; Mullins, Andrew; Porter, Greg; Blanton, Hunter; Johnstone, Connor; Kistler, Ben; Olivera, Daniela

    2017-09-01

    The search for the electric dipole moment of the neutron requires the ambient magnetic field to be on the pT scale which is accomplished with large magnetic shielding rooms. These rooms are fitted with large mu-metal sheets to allow for passive cancellation of background magnetic fields. Active shielding technology cannot uniformly cancel background magnetic fields. These issues can be remedied by combining the methods into a hybrid system. The design used is composed of panels that have an active layer of cancellation between two sheets of mu-metal. The panels form a cube and draw in magnetic fields perpendicular to the surface which can then be reduced using active shielding. This work is supported by the Department of Energy under Contract DE-SC0008107.

  13. Preparation of ZnO/CdS/BC Photocatalyst Hybrid Fiber and Research of Its Photocatalytic Properties

    Directory of Open Access Journals (Sweden)

    Beibei Dai

    2015-01-01

    Full Text Available An environment-friendly biomaterial bacterial cellulose (BC is introduced to substitute general organic polymers to assist the preparation of ZnO/CdS/BC photocatalyst hybrid nanofiber through coprecipitation method under the low-temperature condition. The XRD, XPS, and SEM results show that high load of ZnO/CdS/BC ternary hybrid fiber can be produced. TGA curves scan shows that ZnO/CdS/BC hybrid fiber has better thermal properties than bacterial cellulose. The UV-Vis spectra of the ZnO/CdS/BC hybrid nanofiber (0, 10, 20, and 50 wt%, resp. show that photocatalytic activities of ZnO/CdS/BC are influenced by the added amount of CdS. The degradation curve of methyl shows that ZnO/CdS/BC nanohybrid fibers exhibit excellent photocatalytic efficiency.

  14. Thermally driven self-healing using copper nanofiber heater

    Science.gov (United States)

    Lee, Min Wook; Jo, Hong Seok; Yoon, Sam S.; Yarin, Alexander L.

    2017-07-01

    Nano-textured transparent heaters made of copper nanofibers (CuNFs) are used to facilitate accelerated self-healing of bromobutyl rubber (BIIR). The heater and BIIR layer are separately deposited on each side of a transparent flexible polyethylene terephthalate (PET) substrate. A pre-notched crack on the BIIR layer was bridged due to heating facilitated by CuNFs. In the corrosion test, a cracked BIIR layer covered a steel substrate. An accelerated self-healing of the crack due to the transparent copper nanofiber heater facilitated an anti-corrosion protective effect of the BIIR layer.

  15. Engineered Polymer Composites Through Electrospun Nanofiber Coating of Fiber Tows

    Science.gov (United States)

    Kohlman, Lee W.; Bakis, Charles; Williams, Tiffany S.; Johnston, James C.; Kuczmarski, Maria A.; Roberts, Gary D.

    2014-01-01

    Composite materials offer significant weight savings in many aerospace applications. The toughness of the interface of fibers crossing at different angles often determines failure of composite components. A method for toughening the interface in fabric and filament wound components using directly electrospun thermoplastic nanofiber on carbon fiber tow is presented. The method was first demonstrated with limited trials, and then was scaled up to a continuous lab scale process. Filament wound tubes were fabricated and tested using unmodified baseline towpreg material and nanofiber coated towpreg.

  16. Polyamic Acid Nanofibers Produced by Needleless Electro spinning

    International Nuclear Information System (INIS)

    Jirsak, O.; Sanetrnik, F.; Hruza, J.; Chaloupek, J.; Sysel, P.

    2010-01-01

    The polyimide precursor (polyamic acid) produced of 4,4'-oxydiphthalic anhydride and 4,4'-oxydianiline was electrospun using needleless electrospinning method. Nonwoven layers consisting of submicron fibers with diameters in the range about 143-470 nm on the polypropylene spunbond supporting web were produced. Filtration properties of these nanofiber layers on the highly permeable polypropylene support namely filtration effectivity and pressure drop were evaluated. Consequently, these polyamic acid fibers were heated to receive polyimide nanofibers. The imidization process has been studied using IR spectroscopy. Some comparisons with the chemically identical polyimide prepared as the film were made.

  17. Eddy Current Assessment of Engineered Components Containing Nanofibers

    Science.gov (United States)

    Ko, Ray T.; Hoppe, Wally; Pierce, Jenny

    2009-03-01

    The eddy current approach has been used to assess engineered components containing nanofibers. Five specimens with different programmed defects were fabricated. A 4-point collinear probe was used to verify the electrical resistivity of each specimen. The liftoff component of the eddy current signal was used to test two extreme cases with different nano contents. Additional eddy current measurements were also used in detecting a missing nano layer simulating a manufacturing process error. The results of this assessment suggest that eddy current liftoff measurement can be a useful tool in evaluating the electrical properties of materials containing nanofibers.

  18. Carbon Nanofiber Electrode Array for Neurochemical Monitoring

    Science.gov (United States)

    Koehne, Jessica E.

    2017-01-01

    A sensor platform based on vertically aligned carbon nanofibers (CNFs) has been developed. Their inherent nanometer scale, high conductivity, wide potential window, good biocompatibility and well-defined surface chemistry make them ideal candidates as biosensor electrodes. Here, we report using vertically aligned CNF as neurotransmitter recording electrodes for application in a smart deep brain stimulation (DBS) device. Our approach combines a multiplexed CNF electrode chip, developed at NASA Ames Research Center, with the Wireless Instantaneous Neurotransmitter Concentration Sensor (WINCS) system, developed at the Mayo Clinic. Preliminary results indicate that the CNF nanoelectrode arrays are easily integrated with WINCS for neurotransmitter detection in a multiplexed array format. In the future, combining CNF based stimulating and recording electrodes with WINCS may lay the foundation for an implantable smart therapeutic system that utilizes neurochemical feedback control while likely resulting in increased DBS application in various neuropsychiatric disorders. In total, our goal is to take advantage of the nanostructure of CNF arrays for biosensing studies requiring ultrahigh sensitivity, high-degree of miniaturization, and selective biofunctionalization.

  19. High thermoelectric performance of graphite nanofibers.

    Science.gov (United States)

    Tran, Van-Truong; Saint-Martin, Jérôme; Dollfus, Philippe; Volz, Sebastian

    2018-02-22

    Graphite nanofibers (GNFs) have been demonstrated to be a promising material for hydrogen storage and heat management in electronic devices. Here, by means of first-principles and transport simulations, we show that GNFs can also be an excellent material for thermoelectric applications thanks to the interlayer weak van der Waals interaction that induces low thermal conductance and a step-like shape in the electronic transmission with mini-gaps, which are necessary ingredients to achieve high thermoelectric performance. This study unveils that the platelet form of GNFs in which graphite layers are perpendicular to the fiber axis can exhibit outstanding thermoelectric properties with a figure of merit ZT reaching 3.55 in a 0.5 nm diameter fiber and 1.1 in a 1.1 nm diameter one. Interestingly, by introducing 14 C isotope doping, ZT can even be enhanced up to more than 5, and more than 8 if we include the effect of finite phonon mean free path, which demonstrates the amazing thermoelectric potential of GNFs.

  20. Preparation of MnO nanofibers by novel hydrothermal treatment of manganese acetate/PVA electrospun nanofiber mats

    Energy Technology Data Exchange (ETDEWEB)

    Barakat, Nasser A.M. [Chemical Engineering Department, Faculty of Engineering, El-Minia University, El-Minia (Egypt); Center for Healthcare Technology Development, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)], E-mail: nasbarakat@yahoo.com; Park, Soo Jin [Center for Healthcare Technology Development, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Khil, Myung Seob [Department of Textile Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Kim, Hak Yong [Center for Healthcare Technology Development, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Textile Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)], E-mail: khy@chonbuk.ac.kr

    2009-06-15

    In the present study, manganese monoxide (MnO) which is hard to prepare because of the chemical activity of the manganese metal has been synthesized in nanofibrous form. An electrospun manganese acetate/poly(vinyl alcohol) nanofiber mats have been hydrothermally treated by novel strategy. The treatment process was based on producing of water gas (Co and H{sub 2}) to eliminate the polymer and reduced the manganese acetate to manganese monoxide. The process was carried out by heating the dried nanofiber mates at 400 deg. C for 3 h in an especial designed reactor in which a stream of water vapor was passing through a bed of an activated carbon. The obtained physiochemical characterization results indicated that the proposed hydrothermal treatment process does have the ability to produce pure MnO nanofibers with good crystallinity.

  1. Preparation of MnO nanofibers by novel hydrothermal treatment of manganese acetate/PVA electrospun nanofiber mats

    International Nuclear Information System (INIS)

    Barakat, Nasser A.M.; Park, Soo Jin; Khil, Myung Seob; Kim, Hak Yong

    2009-01-01

    In the present study, manganese monoxide (MnO) which is hard to prepare because of the chemical activity of the manganese metal has been synthesized in nanofibrous form. An electrospun manganese acetate/poly(vinyl alcohol) nanofiber mats have been hydrothermally treated by novel strategy. The treatment process was based on producing of water gas (Co and H 2 ) to eliminate the polymer and reduced the manganese acetate to manganese monoxide. The process was carried out by heating the dried nanofiber mates at 400 deg. C for 3 h in an especial designed reactor in which a stream of water vapor was passing through a bed of an activated carbon. The obtained physiochemical characterization results indicated that the proposed hydrothermal treatment process does have the ability to produce pure MnO nanofibers with good crystallinity.

  2. Dense sheet Z-pinches

    International Nuclear Information System (INIS)

    Tetsu, Miyamoto

    1999-01-01

    The steady state and quasi-steady processes of infinite- and finite-width sheet z-pinches are studied. The relations corresponding to the Bennett relation and Pease-Braginskii current of cylindrical fiber z-pinches depend on a geometrical factor in the sheet z-pinches. The finite-width sheet z-pinch is approximated by a segment of infinite-width sheet z-pinch, if it is wide enough, and corresponds to a number of (width/thickness) times fiber z-pinch plasmas of the diameter that equals the sheet thickness. If the sheet current equals this number times the fiber current, the plasma created in the sheet z-pinches is as dense as in the fiber z-pinches. The total energy of plasma and magnetic field per unit mass is approximately equal in both pinches. Quasi-static transient processes are different in several aspects from the fiber z-pinch. No radiation collapse occurs in the sheet z-pinch. The stability is improved in the sheet z-pinches. The fusion criterions and the experimental arrangements to produce the sheet z-pinches are also discussed. (author)

  3. Perforation of metal sheets

    DEFF Research Database (Denmark)

    Steenstrup, Jens Erik

    simulation is focused on the sheet deformation. However, the effect on the tool and press is included. The process model is based on the upper bound analysis in order to predict the force progress and hole characteristics etc. Parameter analyses are divided into two groups, simulation and experimental tests......The main purposes of this project are:1. Development of a dynamic model for the piercing and performation process2. Analyses of the main parameters3. Establishing demands for process improvements4. Expansion of the existing parameter limitsThe literature survey describes the process influence...

  4. Surface modification of polyvinyl alcohol/malonic acid nanofibers by gaseous dielectric barrier discharge plasma for glucose oxidase immobilization

    Science.gov (United States)

    Afshari, Esmail; Mazinani, Saeedeh; Ranaei-Siadat, Seyed-Omid; Ghomi, Hamid

    2016-11-01

    Polymeric nanofiber prepares a suitable situation for enzyme immobilization for variety of applications. In this research, we have fabricated polyvinyl alcohol (PVA)/malonic acid nanofibers using electrospinning. After fabrication of nanofibers, the effect of air, nitrogen, CO2, and argon DBD (dielectric barrier discharge) plasmas on PVA/malonic acid nanofibers were analysed. Among them, air plasma had the most significant effect on glucose oxidase (GOx) immobilization. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrum analysis and X-ray photoelectron spectroscopy (XPS) results revealed that in case of air plasma modified nanofibers, the carboxyl groups on the surface are increased. The scanning electron microscopy (SEM) images showed that, after GOx immobilization, the modified nanofibers with plasma has retained its nanofiber structure. Finally, we analysed reusability and storage stability of GOx immobilized on plasma modified and unmodified nanofibers. The results were more satisfactory for modified nanofibers with respect to unmodified ones.

  5. Controlled Growth of NiCo2O4 Nanorods and Ultrathin Nanosheets on Carbon Nanofibers for High-performance Supercapacitors

    Science.gov (United States)

    Zhang, Genqiang; (David) Lou, Xiong Wen

    2013-01-01

    Two one-dimensional hierarchical hybrid nanostructures composed of NiCo2O4 nanorods and ultrathin nanosheets on carbon nanofibers (CNFs) are controllably synthesized through facile solution methods combined with a simple thermal treatment. The structure of NiCo2O4 can be easily controlled to be nanorods or nanosheets by using different additives in the synthesis. These two different nanostructures are evaluated as electrodes for high performance supercapacitors, in view of their apparent advantages, such as high electroactive surface area, ultrathin and porous features, robust mechanical strength, shorter ion and electron transport path. Their electrochemical performance is systematically studied, and both of these two hierarchical hybrid nanostructures exhibit high capacitance and excellent cycling stability. The remarkable electrochemical performance will undoubtedly make these hybrid structures attractive for high-performance supercapacitors with high power and energy densities. PMID:23503561

  6. Co- and defect-rich carbon nanofiber films as a highly efficient electrocatalyst for oxygen reduction

    Science.gov (United States)

    Kim, Il To; Song, Myeong Jun; Shin, Seoyoon; Shin, Moo Whan

    2018-03-01

    Many efforts are continuously devoted to developing high-efficiency, low-cost, and highly scalable oxygen reduction reaction (ORR) electrocatalysts to replace precious metal catalysts. Herein, we successfully synthesize Co- and defect-rich carbon nanofibers (CNFs) using an efficient heat treatment approach involving the pyrolysis of electrospun fibers at 370 °C under air. The heat treatment process produces Co-decorated CNFs with a high Co mass ratio, enriched pyridinic N, Co-pyridinic Nx clusters, and defect-rich carbon structures. The synergistic effects from composition and structural changes in the designed material increase the number of catalytically active sites for the ORR in an alkaline solution. The prepared Co- and defect-rich CNFs exhibit excellent ORR activities with a high ORR onset potential (0.954 V vs. RHE), a large reduction current density (4.426 mA cm-2 at 0.40 V), and a nearly four-electron pathway. The catalyst also exhibits a better long-term durability than commercial Pt/C catalysts. This study provides a novel hybrid material as an efficient ORR catalyst and important insight into the design strategy for CNF-based hybrid materials as electrochemical electrodes.

  7. Lysozyme-immobilized electrospun PAMA/PVA and PSSA-MA/PVA ion-exchange nanofiber for wound healing.

    Science.gov (United States)

    Tonglairoum, Prasopchai; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Opanasopit, Praneet

    2014-08-27

    Abstract This research was aimed to develop the lysozyme immobilized ion-exchange nanofiber mats for wound healing. To promote the healing process, the PSSA-MA/PVA and PAMA ion-exchange nanofiber mats were fabricated to mimic the extracellular matrix structure using electrospinning process followed by thermally crosslinked. Lysozyme was immobilized on the ion-exchane nanofibers by an adsorption method. The ion-exchange nanofibers were investigated using SEM, FTIR and XRPD. Moreover, the lysozyme-immobilized ion-exchange nanofibers were further investigated for lysozyme content and activity, lysozyme release and wound healing activity. The fiber diameters of the mats were in the nanometer range. Lysozyme was gradually absorbed into the PSSA-MA/PVA nanofiber with higher extend than that is absorbed on the PAMA/PVA nanofiber and exhibited higher activity than lysozyme-immobilized PAMA/PVA nanofiber. The total contents of lysozyme on the PSSA-MA/PVA and PAMA/PVA nanofiber were 648 and 166 µg/g, respectively. FTIR and lysozyme activity results confirmed the presence of lysozyme on the nanofiber mats. The lysozyme was released from the PSSA-MA/PVA and PAMA/PVA nanofiber in the same manner. The lysozyme-immobilized PSSA-MA/PVA nanofiber mats and lysozyme-immobilized PAMA/PVA nanofiber mats exhibited significantly faster healing rate than gauze and similar to the commercial antibacterial gauze dressing. These results suggest that these nanofiber mats could provide the promising candidate for wound healing application.

  8. Incorporation of functionalized gold nanoparticles into nanofibers for enhanced attachment and differentiation of mammalian cells

    Directory of Open Access Journals (Sweden)

    Jung Dongju

    2012-06-01

    Full Text Available Abstract Background Electrospun nanofibers have been widely used as substrata for mammalian cell culture owing to their structural similarity to natural extracellular matrices. Structurally consistent electrospun nanofibers can be produced with synthetic polymers but require chemical modification to graft cell-adhesive molecules to make the nanofibers functional. Development of a facile method of grafting functional molecules on the nanofibers will contribute to the production of diverse cell type-specific nanofiber substrata. Results Small molecules, peptides, and functionalized gold nanoparticles were successfully incorporated with polymethylglutarimide (PMGI nanofibers through electrospinning. The PMGI nanofibers functionalized by the grafted AuNPs, which were labeled with cell-adhesive peptides, enhanced HeLa cell attachment and potentiated cardiomyocyte differentiation of human pluripotent stem cells. Conclusions PMGI nanofibers can be functionalized simply by co-electrospinning with the grafting materials. In addition, grafting functionalized AuNPs enable high-density localization of the cell-adhesive peptides on the nanofiber. The results of the present study suggest that more cell type-specific synthetic substrata can be fabricated with molecule-doped nanofibers, in which diverse functional molecules are grafted alone or in combination with other molecules at different concentrations.

  9. Osteoinductive peptide-functionalized nanofibers with highly ordered structure as biomimetic scaffolds for bone tissue engineering.

    Science.gov (United States)

    Gao, Xiang; Zhang, Xiaohong; Song, Jinlin; Xu, Xiao; Xu, Anxiu; Wang, Mengke; Xie, Bingwu; Huang, Enyi; Deng, Feng; Wei, Shicheng

    2015-01-01

    The construction of functional biomimetic scaffolds that recapitulate the topographical and biochemical features of bone tissue extracellular matrix is now of topical interest in bone tissue engineering. In this study, a novel surface-functionalized electrospun polycaprolactone (PCL) nanofiber scaffold with highly ordered structure was developed to simulate the critical features of native bone tissue via a single step of catechol chemistry. Specially, under slightly alkaline aqueous solution, polydopamine (pDA) was coated on the surface of aligned PCL nanofibers after electrospinning, followed by covalent immobilization of bone morphogenetic protein-7-derived peptides onto the pDA-coated nanofiber surface. Contact angle measurement, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the presence of pDA and peptides on PCL nanofiber surface. Our results demonstrated that surface modification with osteoinductive peptides could improve cytocompatibility of nanofibers in terms of cell adhesion, spreading, and proliferation. Most importantly, Alizarin Red S staining, quantitative real-time polymerase chain reaction, immunostaining, and Western blot revealed that human mesenchymal stem cells cultured on aligned nanofibers with osteoinductive peptides exhibited enhanced osteogenic differentiation potential than cells on randomly oriented nanofibers. Furthermore, the aligned nanofibers with osteoinductive peptides could direct osteogenic differentiation of human mesenchymal stem cells even in the absence of osteoinducting factors, suggesting superior osteogenic efficacy of biomimetic design that combines the advantages of osteoinductive peptide signal and highly ordered nanofibers on cell fate decision. The presented peptide-decorated bone-mimic nanofiber scaffolds hold a promising potential in the context of bone tissue engineering.

  10. Formation of high aspect ratio polyamide-6 nanofibers via electrically induced double layer during electrospinning

    International Nuclear Information System (INIS)

    Nirmala, R.; Nam, Ki Taek; Park, Soo-Jin; Shin, Yu-Shik; Navamathavan, R.; Kim, Hak Yong

    2010-01-01

    In the present study, the formation of high aspect ratio nanofibers in polyamide-6 was investigated as a function of applied voltage ranging from 15 to 25 kV using electrospinning technique. All other experimental parameters were kept constant. The electrospun polyamide-6 nanofibers were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF). FE-SEM images of polyamide-6 nanofibers showed that the diameter of the electrospun fiber was decreased with increasing applied voltage. At the critical applied voltage, the polymer solution was completely ionized to form the dense high aspect ratio nanofibers in between the main nanofibers. The diameter of the polyamide-6 nanofibers was observed to be in the range of 75-110 nm, whereas the high aspect ratio structures consisted of regularly distributed very fine nanofibers with diameters of about 9-28 nm. Trends in fiber diameter and diameter distribution were discussed for the high aspect ratio nanofibers. TEM results revealed that the formation of double layers in polyamide-6 nanofibers and then split-up into ultrafine fibers. The electrically induced double layer in combination with the polyelectrolytic nature of solution is proposed as the suitable mechanisms for the formation of high aspect ratio nanofibers in polyamide-6.

  11. Influence of polyvinyl alcohol amount on producing in situ photo-crosslinked thioamide functionalized nanofiber membranes

    Directory of Open Access Journals (Sweden)

    Zeytuncu Bihter

    2015-01-01

    Full Text Available Poly(vinyl alcohol/maleic anhydride/acryloyl thioamide monomer (PVA/MA/ATM photo-cured nanofiber membranes and pure PVA nanofiber membranes were produced by electrospinning technique. In situ UV radiation was applied during the electrospinning in order to provide polymerization during the jet flight and promote crosslinking of ATM and MA with PVA. The cross-linking was examined by Fourier-transform infrared spectroscopy (FTIR. The morphology and thermal behavior of electrospun nanofiber were characterized by scanning electron microscope (SEM and thermogravimetric analysis (TGA, respectively. The surface area of nanofiber membranes was measured by Brunauer-Emmert-Teller (BET analysis. Furthermore, water durability test was examined. Water durability test demonstrated that in situ photo-cured PVA/MA/ATM nanofiber membrane had the least average mass loss. The surface areas of PVA/MA/ATM nanofiber membranes were 160-280 m2/g. The surface area and diameter of PVA/MA/ATM nanofibers decreased as the PVA content increased. The diameter of nanofibers was obtained less than 100 nm. The results showed that the water-insoluble nanofiber membranes with better chemical and thermal resistance were obtained. These nanofiber membranes may be a promising candidate for the usage of water treatment.

  12. Preparation of Ag/HBP/PAN Nanofiber Web and Its Antimicrobial and Filtration Property

    Directory of Open Access Journals (Sweden)

    Li-Rong Yao

    2016-01-01

    Full Text Available To widen the application of nanofibers web in the field of medical health materials, a new Ag/amino-terminated hyperbranched polymer (HBP/polyacrylonitrile (PAN nanofiber web with excellent antimicrobial activity and filtration property was produced with Ag/HBP dispersion solution and PAN nanofiber. Ag/HBP dispersion solution was prepared with HBP as reducer and stabilizer, and Ag/HBP/PAN nanofiber was prepared by modifying electrospun PAN nanofiber with Ag/HBP aqueous solution. The characterization results showed that spherical Ag nanoparticles were prepared and they had a narrow distribution in HBP aqueous solution. The results of Ag/HBP/PAN nanofiber characterized with SEM and EDS showed that the content of silver nanoparticles on the surface of PAN nanofiber was on the increase when the treating temperature rose. The bacterial reduction rates of HBP-treated PAN nanofiber against S. aureus and E. coli were about 89%, while those of the Ag/HBP/PAN nanofiber against S. aureus and E. coli were 99.9% and 99.96%, respectively, due to the cooperative effects from the amino groups in HBP and Ag nanoparticles. Moreover, the small pores and high porosity in Ag/HBP/PAN nanofiber web resulted in high filtration efficiency (99.9% for removing smaller particles (0.1 μm~0.7 μm, which was much higher than that of the gauze mask.

  13. Physico-chemical/biological properties of tripolyphosphate cross-linked chitosan based nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Soumi Dey [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur-721302 (India); Farrugia, Brooke L.; Dargaville, Tim R. [Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Groove, Queensland-4059 (Australia); Dhara, Santanu, E-mail: sdhara@smst.iitkgp.ernet.in [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur-721302 (India)

    2013-04-01

    In this study, chitosan-PEO blend, prepared in a 15 M acetic acid, was electrospun into nanofibers (∼ 78 nm diameter) with bead free morphology. While investigating physico-chemical parameters of blend solutions, effect of yield stress on chitosan based nanofiber fabrication was clearly evidenced. Architectural stability of nanofiber mat in aqueous medium was achieved by ionotropic cross-linking of chitosan by tripolyphosphate (TPP) ions. The TPP cross-linked nanofiber mat showed swelling up to ∼ 300% in 1 h and ∼ 40% degradation during 30 day study period. 3T3 fibroblast cells showed good attachment, proliferation and viability on TPP treated chitosan based nanofiber mats. The results indicate non-toxic nature of TPP cross-linked chitosan based nanofibers and their potential to be explored as a tissue engineering matrix. - Highlights: ► Chitosan based nanofiber fabrication through electrospinning. ► Roles of solution viscosity and yield stress on spinnability of chitosan evidenced. ► Tripolyphosphate (TPP) cross-linking rendered structural stability to nanofibers. ► TPP cross-linking also improved cellular response on chitosan based nanofibers. ► Thus, chitosan based nanofibers are suitable for tissue engineering application.

  14. Physico-chemical/biological properties of tripolyphosphate cross-linked chitosan based nanofibers

    International Nuclear Information System (INIS)

    Sarkar, Soumi Dey; Farrugia, Brooke L.; Dargaville, Tim R.; Dhara, Santanu

    2013-01-01

    In this study, chitosan-PEO blend, prepared in a 15 M acetic acid, was electrospun into nanofibers (∼ 78 nm diameter) with bead free morphology. While investigating physico-chemical parameters of blend solutions, effect of yield stress on chitosan based nanofiber fabrication was clearly evidenced. Architectural stability of nanofiber mat in aqueous medium was achieved by ionotropic cross-linking of chitosan by tripolyphosphate (TPP) ions. The TPP cross-linked nanofiber mat showed swelling up to ∼ 300% in 1 h and ∼ 40% degradation during 30 day study period. 3T3 fibroblast cells showed good attachment, proliferation and viability on TPP treated chitosan based nanofiber mats. The results indicate non-toxic nature of TPP cross-linked chitosan based nanofibers and their potential to be explored as a tissue engineering matrix. - Highlights: ► Chitosan based nanofiber fabrication through electrospinning. ► Roles of solution viscosity and yield stress on spinnability of chitosan evidenced. ► Tripolyphosphate (TPP) cross-linking rendered structural stability to nanofibers. ► TPP cross-linking also improved cellular response on chitosan based nanofibers. ► Thus, chitosan based nanofibers are suitable for tissue engineering application

  15. A nanofiber functionalized with dithizone by co-electrospinning for lead (II) adsorption from aqueous media

    International Nuclear Information System (INIS)

    Deng, Jianjun; Kang, Xuejun; Chen, Liqin; Wang, Yu; Gu, Zhongze; Lu, Zuhong

    2011-01-01

    Highlights: ► We fabricated a composite electrospun nanofiber as a selective sorbent for lead (II) in PFSPE. ► The composite nanofiber was functionalized with the dithizone by co-electrospinning of the PS solution containing unbonded dithizone. ► The nanofiber was characterized by scanning electron microscope and IR spectra. ► We applied the nanofiber by packing in a cartridge. ► The nanofiber performed well in the absorption of lead (II) and was applied successfully in aqueous samples. - Abstract: An electrospun nanofiber was utilized as a sorbent in packed fiber solid phase extraction (PFSPE) for selective separation and preconcentration of lead (II). The nanofiber had a polystyrene (PS) backbone, which was functionalized with dithizone (DZ) by co-electrospinning of a PS solution containing DZ. The nanofiber exhibited its performance in a cartridge prepared by packing 5 mg of nanofiber. The nanofiber was characterized by a scanning electron microscope and IR spectra. The diameter of the nanofiber was less than 400 nm. After being activated by 2.0 mol L −1 NaOH aqueous solution, the nanofiber quantitatively sorbed lead (II) at pH 8.5, and the metal ion could be desorbed from it by three times of elution with a small volume of 0.1 mol L −1 HNO 3 aqueous solution. The breakthrough capacity was 16 μg mg −1 . The nanofiber could be used for concentration of lead (II) from water and other aqueous media, such as plasma with stable recovery in a simple and convenient manner.

  16. Experiments on sheet metal shearing

    OpenAIRE

    Gustafsson, Emil

    2013-01-01

    Within the sheet metal industry, different shear cutting technologies are commonly used in several processing steps, e.g. in cut to length lines, slitting lines, end cropping etc. Shearing has speed and cost advantages over competing cutting methods like laser and plasma cutting, but involves large forces on the equipment and large strains in the sheet material.Numerical models to predict forces and sheared edge geometry for different sheet metal grades and different shear parameter set-ups a...

  17. Electrospun Nanofiber Scaffolds with Gradations in Fiber Organization

    Science.gov (United States)

    Khandalavala, Karl; Jiang, Jiang; Shuler, Franklin D.; Xie, Jingwei

    2015-01-01

    The goal of this protocol is to report a simple method for generating nanofiber scaffolds with gradations in fiber organization and test their possible applications in controlling cell morphology/orientation. Nanofiber organization is controlled with a new fabrication apparatus that enables the gradual decrease of fiber organization in a scaffold. Changing the alignment of fibers is achieved through decreasing deposition time of random electrospun fibers on a uniaxially aligned fiber mat. By covering the collector with a moving barrier/mask, along the same axis as fiber deposition, the organizational structure is easily controlled. For tissue engineering purposes, adipose-derived stem cells can be seeded to these scaffolds. Stem cells undergo morphological changes as a result of their position on the varied organizational structure, and can potentially differentiate into different cell types depending on their locations. Additionally, the graded organization of fibers enhances the biomimicry of nanofiber scaffolds so they more closely resemble the natural orientations of collagen nanofibers at tendon-to-bone insertion site compared to traditional scaffolds. Through nanoencapsulation, the gradated fibers also afford the possibility to construct chemical gradients in fiber scaffolds, and thereby further strengthen their potential applications in fast screening of cell-materials interaction and interfacial tissue regeneration. This technique enables the production of continuous gradient scaffolds, but it also can potentially produce fibers in discrete steps by controlling the movement of the moving barrier/mask in a discrete fashion. PMID:25938562

  18. Functionalized carbon nanofibers as solid acid catalysts for transesterification

    NARCIS (Netherlands)

    Stellwagen, D.R.; van der Klis, Frits; van Es, D.S.; de Jong, K.P.; Bitter, J.H.

    2013-01-01

    Carbon nanofibers (CNFs) were functionalized with aryl sulfonic acid groups using in situ diazonium coupling. The use of diazonium coupling yielded an acidic carbon material, in which the introduced acidic groups are readily accessible to the triglyceride substrate. The material is an efficient

  19. Functionalized carbon nanofibers as solid-acid catalysts for transesterification

    NARCIS (Netherlands)

    Stellwagen, D.R.; Klis, van der F.; Es, van D.S.; Jong, de K.P.; Bitter, J.H.

    2013-01-01

    Carbon nanofibers (CNFs) were functionalized with aryl sulfonic acid groups using in situ diazonium coupling. The use of diazonium coupling yielded an acidic carbon material, in which the introduced acidic groups are readily accessible to the triglyceride substrate. The material is an efficient

  20. Preparation and electrochemical properties of polyaniline nanofibers using ultrasonication

    Energy Technology Data Exchange (ETDEWEB)

    Manuel, James [Department of Chemical and Biological Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of); Kim, Miso [Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of); Fapyane, Deby; Chang, In Seop [School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, 261 Cheomdan Gwagi-ro, Buk-gu, Gwangju 500-712 (Korea, Republic of); Ahn, Hyo-Jun, E-mail: ahj@gnu.ac.kr [Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of); Ahn, Jou-Hyeon, E-mail: jhahn@gnu.ac.kr [Department of Chemical and Biological Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of); Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of)

    2014-10-15

    Highlights: • Nanofibrous structured polyaniline (PANI) was prepared by simple ultrasonication. • PANI nanofibers prepared at 5 °C are uniform with an average diameter of 50 nm. • The conductivity is increased by 2 × 10{sup 8} times after doping with LiClO{sub 4}. • The cell with PANI-LiClO{sub 4} shows good cycle performance at high current densities. - Abstract: Polyaniline nanofibers have been successfully prepared by applying ultrasonic irradiation during oxidative polymerization of aniline in dilute hydrochloric acid and evaluated for suitability in lithium cells after doping with lithium perchlorate salt. Polyaniline nanofibers are confirmed by Fourier transform infrared spectroscopy, Fourier transform Raman spectroscopy, and transmission electron microscopy, and the efficiency of doping is confirmed by DC conductivity measurements at different temperatures. Electrochemical properties of nanofibers are evaluated, of which a remarkable increase in cycle stability is achieved when compared to polyaniline prepared by simple oxidative polymerization of aniline. The cell with nanofibrous polyaniline doped with LiClO{sub 4} delivers an initial discharge capacity value of 86 mA h g{sup −1} at 1 C-rate which is about 60% of theoretical capacity, and the capacity is slightly lowered during cycle and reaches 50% of theoretical capacity after 40 cycles. The cell delivers a stable and higher discharge capacity even at 2 C-rate compared to that of the cell prepared with bulk polyaniline doped with LiClO{sub 4}.

  1. Electrospun propolis/polyurethane composite nanofibers for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong In [Department of Bio-nano System Engineering, Chonbuk National University, Jeonju 561–756 (Korea, Republic of); Pant, Hem Raj, E-mail: hempant@jbnu.ac.kr [Department of Bio-nano System Engineering, Chonbuk National University, Jeonju 561–756 (Korea, Republic of); Department of Engineering Science and Humanities, Pulchowk Campus, Tribhuvan University, Kathmandu (Nepal); Research Institute for Next Generation, Kalanki, Kathmandu (Nepal); Sim, Hyun-Jaung [Department of Bioactive Material Science, Research Center of Bioactive Material, Chonbuk National University, Jeonju, Chonbuk (Korea, Republic of); Lee, Kang Min [Department of Molecular Biology, College of Natural Science, Chonbuk National University, Jeonju, 561–756 (Korea, Republic of); Kim, Cheol Sang, E-mail: chskim@jbnu.ac.kr [Department of Bio-nano System Engineering, Chonbuk National University, Jeonju 561–756 (Korea, Republic of)

    2014-11-01

    Tissue engineering requires functional polymeric membrane for adequate space for cell migration and attachment within the nanostructure. Therefore, biocompatible propolis loaded polyurethane (propolis/PU) nanofibers were successfully prepared using electrospinning of propolis/PU blend solution. Here, composite nanofibers were subjected to detailed analysis using electron microscopy, FT-IR spectroscopy, thermal gravimetric analysis (TGA), and mechanical properties and water contact angle measurement. FE-SEM images revealed that the composite nanofibers became point-bonded with increasing amounts of propolis in the blend due to its adhesive properties. Incorporation of small amount of propolis through PU matrix could improve the hydrophilicity and mechanical strength of the fibrous membrane. In order to assay the cytocompatibility and cell behavior on the composite scaffolds, fibroblast cells were seeded on the matrix. Results suggest that the incorporation of propolis into PU fibers could increase its cell compatibility. Moreover, composite nanofibers have effective antibacterial activity. Therefore, as-synthesized nanocomposite fibrous mat has great potentiality in wound dressing and skin tissue engineering. - Highlights: • Sufficient amount of propolis is simply loaded through PU fibers. • Propolis increases the hydrophilicity and mechanical properties of PU fibers. • Composite mat shows excellent antibacterial activity. • Small amount of propolis can enhance the cell compatibility of PU fibers.

  2. Surface plasmon polariton propagation in organic nanofiber based plasmonic waveguides

    DEFF Research Database (Denmark)

    Leißner, Till; Lemke, Christoph; Jauernik, Stephan

    2013-01-01

    Plasmonic wave packet propagation is monitored in dielectric-loaded surface plasmon polariton waveguides realized from para-hexaphenylene nanofibers deposited onto a 60 nm thick gold film. Using interferometric time resolved two-photon photoemission electron microscopy we are able to determine...

  3. Reducing bleaching effects in organic nanofibers by coating

    DEFF Research Database (Denmark)

    Tavares, Luciana; Kjelstrup-Hansen, Jakob; Rubahn, Horst-Günter

    Para-hexaphenylene (p-6P) organic nanofibers emit polarized, blue light upon UV excitation with a peak wavelength of the emitted light of 425 nm [1] and a spatially anisotropic distribution of the emitted light [2]. These features could enable future (opto-)electronic applications [3], since...

  4. Nanofibers extraction from palm mesocarp fiber for biodegradable polymers incorporation

    International Nuclear Information System (INIS)

    Kuana, Vanessa A.; Rodrigues, Vanessa B.; Takahashi, Marcio C.; Campos, Adriana de; Sena Neto, Alfredo R.; Mattoso, Luiz H.C.; Marconcini, Jose M.

    2015-01-01

    The palm mesocarp fibers are residues produced by the palm oil industries. The objective of this paper is to determine an efficient treatment to extract crystal cellulose nanofibers from the palm mesocarp fibers to be incorporated in biodegradable polymeric composites. The fibers were saponified, bleached and analyzed with thermal gravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. (author)

  5. Carbon Nanofibers as Catalyst Support for Noble Metals

    NARCIS (Netherlands)

    Toebes, M.L.

    2004-01-01

    In the quest for new and well-defined support materials for heterogeneous catalysts we explored the potential of carbon nanofibers (CNF). CNF belongs to the by now extensive family of synthetic graphite-like carbon materials with advantageous and tunable physico-chemical properties. Aim of the work

  6. Electrospun propolis/polyurethane composite nanofibers for biomedical applications

    International Nuclear Information System (INIS)

    Kim, Jeong In; Pant, Hem Raj; Sim, Hyun-Jaung; Lee, Kang Min; Kim, Cheol Sang

    2014-01-01

    Tissue engineering requires functional polymeric membrane for adequate space for cell migration and attachment within the nanostructure. Therefore, biocompatible propolis loaded polyurethane (propolis/PU) nanofibers were successfully prepared using electrospinning of propolis/PU blend solution. Here, composite nanofibers were subjected to detailed analysis using electron microscopy, FT-IR spectroscopy, thermal gravimetric analysis (TGA), and mechanical properties and water contact angle measurement. FE-SEM images revealed that the composite nanofibers became point-bonded with increasing amounts of propolis in the blend due to its adhesive properties. Incorporation of small amount of propolis through PU matrix could improve the hydrophilicity and mechanical strength of the fibrous membrane. In order to assay the cytocompatibility and cell behavior on the composite scaffolds, fibroblast cells were seeded on the matrix. Results suggest that the incorporation of propolis into PU fibers could increase its cell compatibility. Moreover, composite nanofibers have effective antibacterial activity. Therefore, as-synthesized nanocomposite fibrous mat has great potentiality in wound dressing and skin tissue engineering. - Highlights: • Sufficient amount of propolis is simply loaded through PU fibers. • Propolis increases the hydrophilicity and mechanical properties of PU fibers. • Composite mat shows excellent antibacterial activity. • Small amount of propolis can enhance the cell compatibility of PU fibers

  7. Phosphopeptide enrichment with inorganic nanofibers prepared by forcespinning technology

    Czech Academy of Sciences Publication Activity Database

    Křenková, Jana; Morávková, J.; Buk, J.; Foret, František

    2016-01-01

    Roč. 1427, JAN (2016), s. 8-15 ISSN 0021-9673 R&D Projects: GA ČR(CZ) GA14-06319S; GA ČR(CZ) GBP206/12/G014 Institutional support: RVO:68081715 Keywords : nanofibers * enrichment * phosphopeptides Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 3.981, year: 2016

  8. Micro-nanofibers with hierarchical structure by bubbfil-spinning

    Directory of Open Access Journals (Sweden)

    Liu Peng

    2015-01-01

    Full Text Available Bubbfil spinning is used to fabricate micro/nanofibers with hierarchical structure. The wall of a polymer film is attenuated unevenly by a blowing air. The burst of the bubble results in film fragments with different thickness, as a result, different sizes of fibers are obtained.

  9. Electrostatic Self-Assembly of Polysaccharides into Nanofibers

    DEFF Research Database (Denmark)

    Mendes, Ana Carina Loureiro; Strohmenger, Timm; Goycoolea, Francisco

    2017-01-01

    In this study, the anionic polysaccharide Xanthan gum (X) was mixed with positively charged Chitosan oligomers (ChO), and used as building blocks, to generate novel nanofibers by electrostatic self-assembly in aqueous conditions. Different concentrations, ionic strength and order of mixing of both...

  10. Silver-functionalized carbon nanofiber composite electrodes for ibuprofen detection

    NARCIS (Netherlands)

    Manea, F.; Motoc, S.; Pop, A.; Remes, A.; Schoonman, J.

    2012-01-01

    The aim of this study is to prepare and characterize two types of silver-functionalized carbon nanofiber (CNF) composite electrodes, i.e., silver-decorated CNF-epoxy and silver-modified natural zeolite-CNF-epoxy composite electrodes suitable for ibuprofen detection in aqueous solution. Ag carbon

  11. Superhydrophobic terpolymer nanofibers containing perfluoroethyl alkyl methacrylate by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Cengiz, Ugur, E-mail: ucengiz@gyte.edu.tr [Department of Chemical Engineering, Gebze Institute of Technology, Cayirova, 41400 Kocaeli (Turkey); Avci, Merih Z. [Polymer Science and Technology, Deparment of Chemistry, Istanbul Technical University, Maslak 34469, Istanbul (Turkey); Erbil, H. Yildirim [Department of Chemical Engineering, Gebze Institute of Technology, Cayirova, 41400 Kocaeli (Turkey); Sarac, A. Sezai [Polymer Science and Technology, Deparment of Chemistry, Istanbul Technical University, Maslak 34469, Istanbul (Turkey)

    2012-05-15

    A new statistical terpolymer containing perfluoroethyl alkyl methacrylate (Zonyl-TM), methyl methacrylate and butyl acrylate, poly(Zonyl-TM-ran-MMA-ran-BA) was synthesized in supercritical carbon dioxide at 200 bar and 80 Degree-Sign C using AIBN as an initiator by heterogeneous free radical copolymerization. Nanofibers of this terpolymer were produced by electrospinning from its DMF solution. The structural and thermal properties of terpolymers and electrospun poly(Zonyl-TM-MMA-BA) nanofibers were analyzed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and differential scanning calorimetry. Nanofiber morphology was investigated by scanning electron microscopy. Electrospun nanofiber layer was found to be superhydrophobic with a water contact angle of 172 {+-} 1 Degree-Sign and highly oleophobic with hexadecane, glycerol and ethylene glycol contact angles of 70 {+-} 1 Degree-Sign , 167 {+-} 1 Degree-Sign and 163 {+-} 1 Degree-Sign respectively. The change of the contact angle results on the electrospun fiber layer and flat terpolymer surfaces by varying feed monomer composition were compared and discussed in the text.

  12. Modeling temperature dependent singlet exciton dynamics in multilayered organic nanofibers

    Science.gov (United States)

    de Sousa, Leonardo Evaristo; de Oliveira Neto, Pedro Henrique; Kjelstrup-Hansen, Jakob; da Silva Filho, Demétrio Antônio

    2018-05-01

    Organic nanofibers have shown potential for application in optoelectronic devices because of the tunability of their optical properties. These properties are influenced by the electronic structure of the molecules that compose the nanofibers and also by the behavior of the excitons generated in the material. Exciton diffusion by means of Förster resonance energy transfer is responsible, for instance, for the change with temperature of colors in the light emitted by systems composed of different types of nanofibers. To study in detail this mechanism, we model temperature dependent singlet exciton dynamics in multilayered organic nanofibers. By simulating absorption and emission spectra, the possible Förster transitions are identified. Then, a kinetic Monte Carlo model is employed in combination with a genetic algorithm to theoretically reproduce time-resolved photoluminescence measurements for several temperatures. This procedure allows for the obtainment of different information regarding exciton diffusion in such a system, including temperature effects on the Förster transfer efficiency and the activation energy of the Förster mechanism. The method is general and may be employed for different systems where exciton diffusion plays a role.

  13. Virucidal Nanofiber Textiles Based on Photosensitized Production of Singlet Oxygen

    Czech Academy of Sciences Publication Activity Database

    Lhotáková, Y.; Plištil, L.; Morávková, A.; Kubát, Pavel; Lang, Kamil; Forstová, J.; Mosinger, J.

    2012-01-01

    Roč. 7, č. 11 (2012), e49226 E-ISSN 1932-6203 R&D Projects: GA ČR GAP208/10/1678 Institutional support: RVO:61388955 ; RVO:61388980 Keywords : photosynthesis * biomaterials * nanofiber textiles Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.730, year: 2012

  14. Dislocation Starvation and Exhaustion Hardening in Mo-alloy Nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Chisholm, Claire [University of California, Berkeley & LBNL; Bei, Hongbin [ORNL; Lowry, M. B. [University of California, Berkeley; Oh, Jason [Hysitron, Inc., MN; Asif, S.A. Syed [Hysitron, Inc., MN; Warren, O. [Hysitron, Inc., MN; Shan, Zhiwei [Xi' an Jiaotong University, China & Hysitron, Inc., MN; George, Easo P [ORNL; Minor, Andrew [University of California, Berkeley & LBNL

    2012-01-01

    The evolution of defects in Mo alloy nanofibers with initial dislocation densities ranging from 0 to 1.6 1014 m2 were studied using an in situ push-to-pull device in conjunction with a nanoindenter in a transmission electron microscope. Digital image correlation was used to determine stress and strain in local areas of deformation. When they had no initial dislocations the Mo alloy nanofibers suffered sudden catastrophic elongation following elastic deformation to ultrahigh stresses. At the other extreme fibers with a high dislocation density underwent sustained homogeneous deformation after yielding at much lower stresses. Between these two extremes nanofibers with intermediate dislocation densities demonstrated a clear exhaustion hardening behavior, where the progressive exhaustion of dislocations and dislocation sources increases the stress required to drive plasticity. This is consistent with the idea that mechanical size effects ( smaller is stronger ) are due to the fact that nanostructures usually have fewer defects that can operate at lower stresses. By monitoring the evolution of stress locally we find that exhaustion hardening causes the stress in the nanofibers to surpass the critical stress predicted for self-multiplication, supporting a plasticity mechanism that has been hypothesized to account for the rapid strain softening observed in nanoscale bcc materials at high stresses.

  15. Zirconium Hydroxide-coated Nanofiber Mats for Nerve Agent Decontamination.

    Science.gov (United States)

    Kim, Sohee; Ying, Wu Bin; Jung, Hyunsook; Ryu, Sam Gon; Lee, Bumjae; Lee, Kyung Jin

    2017-03-16

    Diverse innovative fabrics with specific functionalities have been developed for requirements such as self-decontamination of chemical/biological pollutants and toxic nerve agents. In this work, Zr(OH) 4 -coated nylon-6,6 nanofiber mats were fabricated for the decontamination of nerve agents. Nylon-6,6 fabric was prepared via the electrospinning process, followed by coating with Zr(OH) 4 , which was obtained by the hydrolysis of Zr(OBu) 4 by a sol-gel reaction on nanofiber surfaces. The reaction conditions were optimized by varying the amounts of Zr(OBu) 4 ,the reaction time, and the temperature of the sol-gel reaction. The composite nanofibers show high decontamination efficiency against diisopropylfluorophosphate, which is a nerve agent analogue, due to its high nucleophilicity that aids in the catalysis of the hydrolysis of the phosphonate ester bonds. Composite nanofiber mats have a large potential and can be applied in specific fields such as military and medical markets. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Morphological Characterization of Nanofibers: Methods and Application in Practice

    Directory of Open Access Journals (Sweden)

    Jakub Širc

    2012-01-01

    Full Text Available Biomedical applications such as wound dressing for skin regeneration, stem cell transplantation, or drug delivery require special demands on the three-dimensional porous scaffolds. Besides the biocompatibility and mechanical properties, the morphology is the most important attribute of the scaffold. Specific surface area, volume, and size of the pores have considerable effect on cell adhesion, growth, and proliferation. In the case of incorporated biologically active substances, their release is also influenced by the internal structure of nanofibers. Although many scientific papers are focused on the preparation of nanofibers and evaluation of biological tests, the morphological characterization was described just briefly as service methods. The aim of this paper is to summarize the methods applicable for morphological characterization of nanofibers and supplement it by the results of our research. Needleless electrospinning technique was used to prepare nanofibers from polylactide, poly(ε-caprolactone, gelatin, and polyamide. Scanning electron microscopy was used to evaluate the fiber diameters and to reveal eventual artifacts in the nanofibrous structure. Nitrogen adsorption/desorption measurements were employed to measure the specific surface areas. Mercury porosimetry was used to determine total porosities and compare pore size distributions of the prepared samples.

  17. Reusable photocatalytic titanium dioxide-cellulose nanofiber films

    Science.gov (United States)

    Alexandra Snyder; Zhenyu Bo; Robert Moon; Jean-Christophe Rochet; Lia. Stanciu

    2013-01-01

    Titanium dioxide (TiO2) is a well-studied photocatalyst that is known to break down organic molecules upon ultraviolet (UV) irradiation. Cellulose nanofibers (CNFs) act as an attractive matrix material for the suspension of photocatalytic particles due to their desirable mechanical and optical properties. In this work, TiO2...

  18. Phosphopeptide enrichment with inorganic nanofibers prepared by forcespinning technology

    Czech Academy of Sciences Publication Activity Database

    Křenková, Jana; Morávková, J.; Buk, J.; Foret, František

    2016-01-01

    Roč. 1427, JAN (2016), s. 8-15 ISSN 0021-9673 R&D Projects: GA ČR(CZ) GA14-06319S; GA ČR(CZ) GBP206/12/G014 Institutional support: RVO:68081715 Keywords : nanofibers * enrichment * phosphopeptides Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.981, year: 2016

  19. Aramid Nanofiber Composites for Energy Storage Applications

    Science.gov (United States)

    Tung, Siu on

    Lithium ion batteries and non-aqueous redox flow batteries represent two of the most important energy storage technologies to efficient electric vehicles and power grid, which are essential to decreasing U.S. dependence on fossil fuels and sustainable economic growth. Many of the developmental roadblocks for these batteries are related to the separator, an electrically insulating layer between the cathode and anode. Lithium dendrite growth has limited the performance and threatened the safety of lithium ion batteries by piercing the separator and causing internal shorts. In non-aqueous redox flow batteries, active material crossover through microporous separators and the general lack of a suitable ion conducting membrane has led to low operating efficiencies and rapid capacity fade. Developing new separators for these batteries involve the combination of different and sometimes seemingly contradictory properties, such as high ionic conductivity, mechanical stability, thermal stability, chemical stability, and selective permeability. In this dissertation, I present work on composites made from Kevlar-drived aramid nanofibers (ANF) through rational design and fabrication techniques. For lithium ion batteries, a dendrite suppressing layer-by-layer composite of ANF and polyethylene oxide is present with goals of high ionic conductivity, improved safety and thermal stability. For non-aqueous redox flow batteries, a nanoporous ANF separator with surface polyelectrolyte modification is used to achieve high coulombic efficiencies and cycle life in practical flow cells. Finally, manufacturability of ANF based separators is addressed through a prototype machine for continuous ANF separator production and a novel separator coated on anode assembly. In combination, these studies serve as a foundation for addressing the challenges in separator engineering for lithium ion batteries and redox flow batteries.

  20. Vapor-phase polymerization of poly(3, 4-ethylenedioxythiophene) nanofibers on carbon cloth as electrodes for flexible supercapacitors

    Science.gov (United States)

    Zhao, Xin; Dong, Mengyang; Zhang, Junxian; Li, Yingzhi; Zhang, Qinghua

    2016-09-01

    In this study, an evaporative vapor-phase polymerization approach was employed to fabricate vertically aligned poly(3, 4-ethylenedioxythiophene) (PEDOT) nanofibers on the surface of carbon cloth (CC). Optimized reaction conditions can obtain well distributed and uniform layers of high-aspect-ratio PEDOT nanofibers on CC. The hierarchical PEDOT/CC structure as a freestanding electrode exhibits good electrochemical properties. As a flexible symmetric supercapacitor, the PEDOT/CC hybrid electrode displays a specific areal capacitance of 201.4 mF cm-2 at 1 mA cm-2, good flexibility with a higher value (204.6 mF cm-2) in the bending state, and a good cycling stability of 92.4% after 1000 cycles. Moreover, the device shows a maximum energy density of 4.0 Wh kg-1 (with a power density of 3.2 kW kg-1) and a maximum power density of 4.2 kW kg-1 (with an energy density of 3.1 Wh kg-1). The results demonstrate that PEDOT may be a promising material for storage devices through a simple and efficient vapor-phase polymerization process with precisely controlled reaction conditions.

  1. The Chemical Deposition Method for the Decoration of Palladium Particles on Carbon Nanofibers with Rapid Conductivity Changes

    Directory of Open Access Journals (Sweden)

    Hoik Lee

    2016-11-01

    Full Text Available Palladium (Pd metal is well-known for hydrogen sensing material due to its high sensitivity and selectivity toward hydrogen, and is able to detect hydrogen at near room temperature. In this work, palladium-doped carbon nanofibers (Pd/CNFs were successfully produced in a facile manner via electrospinning. Well-organized and uniformly distributed Pd was observed in microscopic images of the resultant nanofibers. Hydrogen causes an increment in the volume of Pd due to the ability of hydrogen atoms to occupy the octahedral interstitial positions within its face centered cubic lattice structure, resulting in the resistance transition of Pd/CNFs. The resistance variation was around 400%, and it responded rapidly within 1 min, even in 5% hydrogen atmosphere conditions at room temperature. This fibrous hybrid material platform will open a new and practical route and stimulate further researches on the development of hydrogen sensing materials with rapid response, even to low concentrations of hydrogen in an atmosphere.

  2. Fabricated nano-fiber diameter as liquid concentration sensors

    Science.gov (United States)

    Chyad, Radhi M.; Mat Jafri, Mohd Zubir; Ibrahim, Kamarulazizi

    Nanofiber is characterized by thin, long, and very soft silica. Taper fibers are made using an easy and low cost chemical method. Etching is conducted with a HF solution to remove cladding and then a low molarity HF solution to reduce the fiber core diameter. One approach to on-line monitoring of the etching process uses spectrophotometer with a white light source. In the aforementioned technique, this method aims to determine the diameter of the reduced core and show the evolution of the two different processes from the nanofiber regime to the fixed regime in which the mode was remote from the surrounding evanescent field, intensity can propagate outside the segment fiber when the core diameter is less than 500 nm. Manufacturing technologies of nano-fiber sensors offer a number of approved properties of optical fiber sensors utilized in various sensory applications. The nano-fiber sensor is utilized to sense the difference in the concentration of D-glucose in double-distilled deionized water and to measure the refractive index (RI) of a sugar solution. Our proposed method exhibited satisfactory capability based on bimolecular interactions in the biological system. The response of the nano-fiber sensors indicates a different kind of interaction among various groups of AAs. These results can be interpreted in terms of solute-solute and solute-solvent interactions and the structure making or breaking ability of solutes in the given solution. This study utilized spectra photonics to measure the transmission of light through different concentrations of sugar solution, employing cell cumber and nano-optical fibers as sensors.

  3. Soft Costs Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-05-01

    This fact sheet is an overview of the systems integration subprogram at the U.S. Department of Energy SunShot Initiative. Soft costs can vary significantly as a result of a fragmented energy marketplace. In the U.S., there are 18,000 jurisdictions and 3,000 utilities with different rules and regulations for how to go solar. The same solar equipment may vary widely in its final installation price due to process and market variations across jurisdictions, creating barriers to rapid industry growth. SunShot supports the development of innovative solutions that enable communities to build their local economies and establish clean energy initiatives that meet their needs, while at the same time creating sustainable solar market conditions.

  4. Photovoltaics Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-02-01

    This fact sheet is an overview of the Photovoltaics (PV) subprogram at the U.S. Department of Energy SunShot Initiative. The U.S. Department of Energy (DOE)’s Solar Energy Technologies Office works with industry, academia, national laboratories, and other government agencies to advance solar PV, which is the direct conversion of sunlight into electricity by a semiconductor, in support of the goals of the SunShot Initiative. SunShot supports research and development to aggressively advance PV technology by improving efficiency and reliability and lowering manufacturing costs. SunShot’s PV portfolio spans work from early-stage solar cell research through technology commercialization, including work on materials, processes, and device structure and characterization techniques.

  5. Systems Integration Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-06-01

    This fact sheet is an overview of the Systems Integration subprogram at the U.S. Department of Energy SunShot Initiative. The Systems Integration subprogram enables the widespread deployment of safe, reliable, and cost-effective solar energy technologies by addressing the associated technical and non-technical challenges. These include timely and cost-effective interconnection procedures, optimal system planning, accurate prediction of solar resources, monitoring and control of solar power, maintaining grid reliability and stability, and many more. To address the challenges associated with interconnecting and integrating hundreds of gigawatts of solar power onto the electricity grid, the Systems Integration program funds research, development, and demonstration projects in four broad, interrelated focus areas: grid performance and reliability, dispatchability, power electronics, and communications.

  6. Hyperspectral light sheet microscopy

    Science.gov (United States)

    Jahr, Wiebke; Schmid, Benjamin; Schmied, Christopher; Fahrbach, Florian O.; Huisken, Jan

    2015-09-01

    To study the development and interactions of cells and tissues, multiple fluorescent markers need to be imaged efficiently in a single living organism. Instead of acquiring individual colours sequentially with filters, we created a platform based on line-scanning light sheet microscopy to record the entire spectrum for each pixel in a three-dimensional volume. We evaluated data sets with varying spectral sampling and determined the optimal channel width to be around 5 nm. With the help of these data sets, we show that our setup outperforms filter-based approaches with regard to image quality and discrimination of fluorophores. By spectral unmixing we resolved overlapping fluorophores with up to nanometre resolution and removed autofluorescence in zebrafish and fruit fly embryos.

  7. Carbon Nanofiber versus Graphene-Based Stretchable Capacitive Touch Sensors for Artificial Electronic Skin.

    Science.gov (United States)

    Cataldi, Pietro; Dussoni, Simeone; Ceseracciu, Luca; Maggiali, Marco; Natale, Lorenzo; Metta, Giorgio; Athanassiou, Athanassia; Bayer, Ilker S

    2018-02-01

    Stretchable capacitive devices are instrumental for new-generation multifunctional haptic technologies particularly suited for soft robotics and electronic skin applications. A majority of elongating soft electronics still rely on silicone for building devices or sensors by multiple-step replication. In this study, fabrication of a reliable elongating parallel-plate capacitive touch sensor, using nitrile rubber gloves as templates, is demonstrated. Spray coating both sides of a rubber piece cut out of a glove with a conductive polymer suspension carrying dispersed carbon nanofibers (CnFs) or graphene nanoplatelets (GnPs) is sufficient for making electrodes with low sheet resistance values (≈10 Ω sq -1 ). The electrodes based on CnFs maintain their conductivity up to 100% elongation whereas the GnPs-based ones form cracks before 60% elongation. However, both electrodes are reliable under elongation levels associated with human joints motility (≈20%). Strikingly, structural damages due to repeated elongation/recovery cycles could be healed through annealing. Haptic sensing characteristics of a stretchable capacitive device by wrapping it around the fingertip of a robotic hand (ICub) are demonstrated. Tactile forces as low as 0.03 N and as high as 5 N can be easily sensed by the device under elongation or over curvilinear surfaces.

  8. Interpenetrated Binary Supramolecular Nanofibers for Sensitive Fluorescence Detection of Six Classes of Explosives.

    Science.gov (United States)

    Xiong, Wei; Zhu, Qijian; Gong, Yanjun; Wang, Chen; Che, Yanke; Zhao, Jincai

    2018-04-03

    In this work, we develop a sequential self-assembly approach to fabricate interpenetrated binary supramolecular nanofibers consisting of carbazole oligomer 1-cobalt(II) (1-Co 2+ ) coordination nanofibers and oligomer 2 nanofibers for the sensitive detection of six classes of explosives. When exposed to peroxide explosives (e.g., H 2 O 2 ), Co 2+ in 1-Co 2+ coordination nanofibers can be reduced to Co + that can transfer an electron to the excited 2 nanofibers and thereby quench their fluorescence. On the other hand, when exposed to the other five classes of explosives, the excited 2 nanofibers can transfer an electron to explosives to quench their fluorescence. On the basis of the distinct fluorescence quenching mechanisms, six classes of explosives can be sensitively detected. Herein, we provide a new strategy to design broad-band fluorescence sensors for a rich identification of threats.

  9. Graft polymerization of acrylic acid onto chitin nanofiber to improve dispersibility in basic water.

    Science.gov (United States)

    Ifuku, Shinsuke; Iwasaki, Masayoshi; Morimoto, Minoru; Saimoto, Hiroyuki

    2012-09-01

    Graft copolymerization of acrylic acid (AA) on chitin nanofibers was carried out with potassium persulfate as a free radical initiator in an aqueous medium. The molar ratio of grafted AA increased with the AA concentration. The grafted chitin nanofibers were characterized by FT-IR, FE-SEM, UV-vis, XRD, and TGA. After polymerization, the characteristic morphology of chitin nanofibers was maintained. Chitin nanofibers grafted with AA were efficiently dissociated and dispersed homogeneously in basic water because of the electrostatic repulsion effect between nanofibers. AA was grafted on the surface and amorphous part of chitin nanofibers, and the original crystalline structure of α-chitin was maintained. At 330 °C, the weight residue of the graft copolymer increased with the grafted AA content. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Dehydration driven changes in the structure and mechanical behavior of electrospun poly (vinyl alcohol) nanofibers

    International Nuclear Information System (INIS)

    Bansal, Ankita; Sinha, Arvind

    2012-01-01

    Electrospun nanofibers of poly (vinyl alcohol) (PVA) are well known for their possible application in different fields, ranging from packaging to tissue engineering. However, biomedical application of these nanofibers gets limited due to its rapid disintegration in water, causing mechanical instability. Addressing this issue, the present manuscript reports ethanol induced dehydration of electrospun PVA nanofibers, and its effects on the structure and mechanical properties of the electrospun system. A systematic variation in the structure and mechanical stability of nanofibers as a function of PVA concentration has also been established in the both hydrated and dehydrated states. - Highlights: ► Study reports structure-property correlation of dehydrated PVA nanofibers. ► Results confirm symmetrical reversal of properties in two states. ► Experimental results are in confirmation with the fusion model of nanofibers.

  11. Biocompatible Electroactive Tetra(aniline)-Conjugated Peptide Nanofibers for Neural Differentiation.

    Science.gov (United States)

    Arioz, Idil; Erol, Ozlem; Bakan, Gokhan; Dikecoglu, F Begum; Topal, Ahmet E; Urel, Mustafa; Dana, Aykutlu; Tekinay, Ayse B; Guler, Mustafa O

    2018-01-10

    Peripheral nerve injuries cause devastating problems for the quality of patients' lives, and regeneration following damage to the peripheral nervous system is limited depending on the degree of the damage. Use of nanobiomaterials can provide therapeutic approaches for the treatment of peripheral nerve injuries. Electroactive biomaterials, in particular, can provide a promising cure for the regeneration of nerve defects. Here, a supramolecular electroactive nanosystem with tetra(aniline) (TA)-containing peptide nanofibers was developed and utilized for nerve regeneration. Self-assembled TA-conjugated peptide nanofibers demonstrated electroactive behavior. The electroactive self-assembled peptide nanofibers formed a well-defined three-dimensional nanofiber network mimicking the extracellular matrix of the neuronal cells. Neurite outgrowth was improved on the electroactive TA nanofiber gels. The neural differentiation of PC-12 cells was more advanced on electroactive peptide nanofiber gels, and these biomaterials are promising for further use in therapeutic neural regeneration applications.

  12. Superhydrophilicity of a nanofiber-covered aluminum surface fabricated via pyrophosphoric acid anodizing

    Science.gov (United States)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2016-12-01

    A superhydrophilic aluminum surface covered by numerous alumina nanofibers was fabricated via pyrophosphoric acid anodizing. High-density anodic alumina nanofibers grow on the bottom of a honeycomb oxide via anodizing in concentrated pyrophosphoric acid. The water contact angle on the nanofiber-covered aluminum surface decreased with time after a 4 μL droplet was placed on the surface, and a superhydrophilic behavior with a contact angle measuring 2.2° was observed within 2 s; this contact angle is considerably lower than those observed for electropolished and porous alumina-covered aluminum surfaces. There was no dependence of the superhydrophilicity on the density of alumina nanofibers fabricated via different constant voltage anodizing conditions. The superhydrophilic property of the surface covered by anodic alumina nanofibers was maintained during an exposure test for 359 h. The quick-drying and snow-sliding behaviors of the superhydrophilic aluminum covered with anodic alumina nanofibers were demonstrated.

  13. Evaluation of carbon fiber composites modified by in situ incorporation of carbon nanofibers

    Directory of Open Access Journals (Sweden)

    André Navarro de Miranda

    2011-12-01

    Full Text Available Nano-carbon materials, such as carbon nanotubes and carbon nanofibers, are being thought to be used as multifunctional reinforcement in composites. The growing of carbon nanofiber at the carbon fiber/epoxy interface results in composites having better electrical properties than conventional carbon fiber/epoxy composites. In this work, carbon nanofibers were grown in situ over the surface of a carbon fiber fabric by chemical vapor deposition. Specimens of carbon fiber/nanofiber/epoxy (CF/CNF/epoxy composites were molded and electrical conductivity was measured. Also, the CF/CNF/epoxy composites were tested under flexure and interlaminar shear. The results showed an overall reduction in mechanical properties as a function of added nanofiber, although electrical conductivity increased up to 74% with the addition of nanofibers. Thus CF/CNF/epoxy composites can be used as electrical dissipation discharge materials.

  14. Electrospun polyvinyl alcohol–collagen–hydroxyapatite nanofibers: a biomimetic extracellular matrix for osteoblastic cells

    International Nuclear Information System (INIS)

    Song Wei; Shi Tong; Ren Weiping; Markel, David C; Wang Sunxi; Mao Guangzhao

    2012-01-01

    The failure of prosthesis after total joint replacement is due to the lack of early implant osseointegration. In this study polyvinyl alcohol–collagen–hydroxyapatite (PVA-Col-HA) electrospun nanofibrous meshes were fabricated as a biomimetic bone-like extracellular matrix for the modification of orthopedic prosthetic surfaces. In order to reinforce the PVA nanofibers, HA nanorods and Type I collagen were incorporated into the nanofibers. We investigated the morphology, biodegradability, mechanical properties and biocompatibility of the prepared nanofibers. Our results showed these inorganic–organic blended nanofibers to be degradable in vitro. The encapsulated nano-HA and collagen interacted with the PVA content, reinforcing the hydrolytic resistance and mechanical properties of nanofibers that provided longer lasting stability. The encapsulated nano-HA and collagen also enhanced the adhesion and proliferation of murine bone cells (MC3T3) in vitro. We propose the PVA-Col-HA nanofibers might be promising modifying materials on implant surfaces for orthopedic applications. (paper)

  15. Fabrication and properties of shape-memory polymer coated with conductive nanofiber paper

    Science.gov (United States)

    Lu, Haibao; Liu, Yanju; Gou, Jan; Leng, Jinsong

    2009-07-01

    A unique concept of shape-memory polymer (SMP) nanocomposites making up of carbon nanofiber paper was explored. The essential element of this method was to design and fabricate nanopaper with well-controlled and optimized network structure of carbon nanofibers. In this study, carbon nanofiber paper was prepared under ultrasonicated processing and vapor press method, while the dispersion of nanofiber was treated by BYK-191 dispersant. The morphologies of carbon nanofibers within the paper were characterized with scanning electron microscopy (SEM). In addition, the thermomechanical properties of SMP coated with carbon nanofiber paper were measured by the dynamic mechanical thermal analysis (DMTA). It was found that the glass transition temperature and thermomechanical properties of nanocomposites were strongly determined by the dispersion of polymer in conductive paper. Subsequently, the electrical conductivity of conductive paper and nanocomposites were measured, respectively. And experimental results revealed that the conductive properties of nanocoposites were significantly improved by carbon nanopaper, resulting in actuation driven by electrical resistive heating.

  16. Fabrication and Characterization of Electrospun Wool Keratin/Poly(vinyl alcohol Blend Nanofibers

    Directory of Open Access Journals (Sweden)

    Shuai Li

    2014-01-01

    Full Text Available Wool keratin/poly(vinyl alcohol (PVA blend nanofibers were fabricated using the electrospinning method in formic acid solutions with different weight ratios of keratin to PVA. The resultant blend nanofibers were characterized by scanning electron microscopy (SEM, Fourier transform infrared (FTIR, X-ray diffraction (XRD, thermal gravimetric analysis (TGA, and tensile test. SEM images showed that the diameter of the blend nanofibers was affected by the content of keratin in blend solution. FTIR and XRD analyses data demonstrated that there were good interactions between keratin and PVA in the blended nanofibers caused by possibly hydrogen bonds. The TGA study revealed that the thermal stability of the blend nanofibers was between those of keratin and PVA. Tensile test indicated that the addition of PVA was able to improve the mechanical properties of the electrospun nanofibers.

  17. Vortex sheet approximation of boundary layers

    International Nuclear Information System (INIS)

    Chorin, A.J.

    1978-01-01

    a grid free method for approximating incomprssible boundary layers is introduced. The computational elements are segments of vortex sheets. The method is related to the earlier vortex method; simplicity is achieved at the cost of replacing the Navier-Stokes equations by the Prandtl boundary layer equations. A new method for generating vorticity at boundaries is also presented; it can be used with the earlier voartex method. The applications presented include (i) flat plate problems, and (ii) a flow problem in a model cylinder- piston assembly, where the new method is used near walls and an improved version of the random choice method is used in the interior. One of the attractive features of the new method is the ease with which it can be incorporated into hybrid algorithms

  18. Settlement during vibratory sheet piling

    NARCIS (Netherlands)

    Meijers, P.

    2007-01-01

    During vibratory sheet piling quite often the soil near the sheet pile wall will settle. In many cases this is not a problem. For situations with houses, pipelines, roads or railroads at relative short distance these settlements may not be acceptable. The purpose of the research described in this

  19. Surface modification of polyvinyl alcohol/malonic acid nanofibers by gaseous dielectric barrier discharge plasma for glucose oxidase immobilization

    International Nuclear Information System (INIS)

    Afshari, Esmail; Mazinani, Saeedeh; Ranaei-Siadat, Seyed-Omid; Ghomi, Hamid

    2016-01-01

    Highlights: • We fabricated polyvinyl alcohol/malonic acid nanofibers using electrospinning. • The surface nanofibers were modified by gaseous (air, nitrogen, CO_2 and argon) dielectric barrier discharge. • Among them, air plasma had the most significant effect on glucose oxidase immobilization. • Chemical analysis showed that after modification of nanofibers by air plasma, the carboxyl group increased. • After air plasma treatment, reusability and storage stability of glucose oxidase immobilized on nanofibers improved. - Abstract: Polymeric nanofiber prepares a suitable situation for enzyme immobilization for variety of applications. In this research, we have fabricated polyvinyl alcohol (PVA)/malonic acid nanofibers using electrospinning. After fabrication of nanofibers, the effect of air, nitrogen, CO_2, and argon DBD (dielectric barrier discharge) plasmas on PVA/malonic acid nanofibers were analysed. Among them, air plasma had the most significant effect on glucose oxidase (GOx) immobilization. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrum analysis and X-ray photoelectron spectroscopy (XPS) results revealed that in case of air plasma modified nanofibers, the carboxyl groups on the surface are increased. The scanning electron microscopy (SEM) images showed that, after GOx immobilization, the modified nanofibers with plasma has retained its nanofiber structure. Finally, we analysed reusability and storage stability of GOx immobilized on plasma modified and unmodified nanofibers. The results were more satisfactory for modified nanofibers with respect to unmodified ones.

  20. Surface modification of polyvinyl alcohol/malonic acid nanofibers by gaseous dielectric barrier discharge plasma for glucose oxidase immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Afshari, Esmail, E-mail: e.afshari@mail.sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, Evin, 1983963113 Tehran (Iran, Islamic Republic of); Mazinani, Saeedeh [Amirkabir Nanotechnology Research Institute (ANTRI), Amirkabir University of Technology, 15875-4413, Tehran (Iran, Islamic Republic of); Ranaei-Siadat, Seyed-Omid [Protein Research Center, Shahid Beheshti University, Evin, 1983963113 Tehran (Iran, Islamic Republic of); Ghomi, Hamid [Laser and Plasma Research Institute, Shahid Beheshti University, Evin, 1983963113 Tehran (Iran, Islamic Republic of)

    2016-11-01

    Highlights: • We fabricated polyvinyl alcohol/malonic acid nanofibers using electrospinning. • The surface nanofibers were modified by gaseous (air, nitrogen, CO{sub 2} and argon) dielectric barrier discharge. • Among them, air plasma had the most significant effect on glucose oxidase immobilization. • Chemical analysis showed that after modification of nanofibers by air plasma, the carboxyl group increased. • After air plasma treatment, reusability and storage stability of glucose oxidase immobilized on nanofibers improved. - Abstract: Polymeric nanofiber prepares a suitable situation for enzyme immobilization for variety of applications. In this research, we have fabricated polyvinyl alcohol (PVA)/malonic acid nanofibers using electrospinning. After fabrication of nanofibers, the effect of air, nitrogen, CO{sub 2}, and argon DBD (dielectric barrier discharge) plasmas on PVA/malonic acid nanofibers were analysed. Among them, air plasma had the most significant effect on glucose oxidase (GOx) immobilization. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrum analysis and X-ray photoelectron spectroscopy (XPS) results revealed that in case of air plasma modified nanofibers, the carboxyl groups on the surface are increased. The scanning electron microscopy (SEM) images showed that, after GOx immobilization, the modified nanofibers with plasma has retained its nanofiber structure. Finally, we analysed reusability and storage stability of GOx immobilized on plasma modified and unmodified nanofibers. The results were more satisfactory for modified nanofibers with respect to unmodified ones.

  1. Photocatalytic and Magnetic Behaviors Observed in BiFeO3 Nanofibers by Electrospinning

    Directory of Open Access Journals (Sweden)

    Xuehui Zhang

    2013-01-01

    Full Text Available Perovskite-type BiFeO3 nanofibers with wave nodes-like morphology were prepared by electrospinning. The nanofibers show a highly enhanced visible-light-active photocatalytic property. The results also showed that the diameter could affect the band gap and photocatalytic performances of nanofibers. Additionally, weak ferromagnetic behaviors can be observed at room temperature, which should be correlated to the size-confinement effect on the magnetic ordering of BiFeO3 structure.

  2. Size-dependent mechanical properties of PVA nanofibers reduced via air plasma treatment

    International Nuclear Information System (INIS)

    Fu Qiang; Song Xuefeng; Gao Jingyun; Han Xiaobing; Zhao Qing; Yu Dapeng; Jin Yu; Jiang Xingyu

    2010-01-01

    Organic nanowires/fibers have great potential in applications such as organic electronics and soft electronic techniques. Therefore investigation of their mechanical performance is of importance. The Young's modulus of poly(vinyl alcohol) (PVA) nanofibers was analyzed by scanning probe microscopy (SPM) methods. Air plasma treatment was used to reduce the nanofibers to different sizes. Size-dependent mechanical properties of PVA nanofibers were studied and revealed that the Young's modulus increased dramatically when the scales became very small (<80 nm).

  3. Size-dependent mechanical properties of PVA nanofibers reduced via air plasma treatment.

    Science.gov (United States)

    Fu, Qiang; Jin, Yu; Song, Xuefeng; Gao, Jingyun; Han, Xiaobing; Jiang, Xingyu; Zhao, Qing; Yu, Dapeng

    2010-03-05

    Organic nanowires/fibers have great potential in applications such as organic electronics and soft electronic techniques. Therefore investigation of their mechanical performance is of importance. The Young's modulus of poly(vinyl alcohol) (PVA) nanofibers was analyzed by scanning probe microscopy (SPM) methods. Air plasma treatment was used to reduce the nanofibers to different sizes. Size-dependent mechanical properties of PVA nanofibers were studied and revealed that the Young's modulus increased dramatically when the scales became very small (<80 nm).

  4. Fabrication of a novel aluminum surface covered by numerous high-aspect-ratio anodic alumina nanofibers

    OpenAIRE

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

    2015-01-01

    The formation behavior of anodic alumina nanofibers via anodizing in a concentrated pyrophosphoric acid under various conditions was investigated using electrochemical measurements and SEM/TEM observations. Pyrophosphoric acid anodizing at 293 K resulted in the formation of numerous anodic alumina nanofibers on an aluminum substrate through a thin barrier oxide and honeycomb oxide with narrow walls. However, long-term anodizing led to the chemical dissolution of the alumina nanofibers. The de...

  5. Fabrication and Characterization of Electrospun Wool Keratin/Poly(vinyl alcohol) Blend Nanofibers

    OpenAIRE

    Shuai Li; Xu-Hong Yang

    2014-01-01

    Wool keratin/poly(vinyl alcohol) (PVA) blend nanofibers were fabricated using the electrospinning method in formic acid solutions with different weight ratios of keratin to PVA. The resultant blend nanofibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and tensile test. SEM images showed that the diameter of the blend nanofibers was affected by the content of keratin in blend solution...

  6. Plasma dynamics in current sheets

    International Nuclear Information System (INIS)

    Bogdanov, S.Yu.; Drejden, G.V.; Kirij, N.P.; AN SSSR, Leningrad

    1992-01-01

    Plasma dynamics in successive stages of current sheet evolution is investigated on the base of analysis of time-spatial variations of electron density and electrodynamic force fields. Current sheet formation is realized in a two-dimensional magnetic field with zero line under the action of relatively small initial disturbances (linear regimes). It is established that in the limits of the formed sheet is concentrated dense (N e ∼= 10 16 cm -3 ) (T i ≥ 100 eV, bar-Z i ≥ 2) hot pressure of which is balanced by the magnetic action of electrodynamic forces is carried out both plasma compression in the sheet limits and the acceleration along the sheet surface from a middle to narrow side edges

  7. Low temperature route synthesis of SiC–Al2O3 hetero-structural nanofibers

    International Nuclear Information System (INIS)

    Dai, Xiao; Wang, Hao; Cao, Fengfeng; Yi, Qinghua; Cong, Shan; Wang, Yun; Song, Pingyuan; Zhai, Pengfei; Zou, Guifu; Dong, Chao

    2014-01-01

    SiC–Al 2 O 3 hetero-structural nanofibers have been synthesized by the chemical solution approach at 200 ° C. The diameters of nanofibers are in the range of 60–100 nm while the lengths are from tens of micrometers to hundreds of micrometers. The microstructural analysis shows that the fibers possess a like-epitaxial relationship between (104) of hexagonal Al 2 O 3 and (111) of cubic SiC. Additionally, the optical investigation of the nanofibers suggests there are some defects in the low annealing temperature synthesized SiC–Al 2 O 3 nanofibers. (paper)

  8. Novel electrospun gelatin/oxycellulose nanofibers as a suitable platform for lung disease modeling

    Energy Technology Data Exchange (ETDEWEB)

    Švachová, Veronika, E-mail: xcsvachova@fch.vutbr.cz [Institute of Materials Chemistry, Brno University of Technology (Czech Republic); Vojtová, Lucy [CEITEC – Central European Institute of Technology, Brno University of Technology (Czech Republic); SCITEG, a.s., Brno (Czech Republic); Pavliňák, David [Department of Physical Electronics, Masaryk University (Czech Republic); Vojtek, Libor [Institute of Experimental Biology, Masaryk University (Czech Republic); Sedláková, Veronika [Department of Histology and Embryology, Masaryk University (Czech Republic); International Clinical Research, St. Anne' s University Hospital, Brno (Czech Republic); Hyršl, Pavel [Institute of Experimental Biology, Masaryk University (Czech Republic); Alberti, Milan [Department of Physical Electronics, Masaryk University (Czech Republic); Jaroš, Josef; Hampl, Aleš [Department of Histology and Embryology, Masaryk University (Czech Republic); International Clinical Research, St. Anne' s University Hospital, Brno (Czech Republic); Jančář, Josef [Institute of Materials Chemistry, Brno University of Technology (Czech Republic); CEITEC – Central European Institute of Technology, Brno University of Technology (Czech Republic); SCITEG, a.s., Brno (Czech Republic)

    2016-10-01

    Novel hydrolytically stable gelatin nanofibers modified with sodium or calcium salt of oxycellulose were prepared by electrospinning method. The unique inhibitory effect of these nanofibers against Escherichia coli bacteria was examined by luminometric method. Biocompatibility of these gelatin/oxycellulose nanofibers with eukaryotic cells was tested using human lung adenocarcinoma cell line NCI-H441. Cells firmly adhered to nanofiber surface, as determined by scanning electron microscopy, and no signs of cell dying were detected by fluorescent live/dead assay. We propose that the newly developed gelatin/oxycellulose nanofibers could be used as promising scaffold for lung disease modeling and anti-cancer drug testing. - Highlights: • Novel hydrolytically stable gelatin nanofibers modified with oxycellulose were prepared by electrospinning. • ATR–FTIR spectroscopy and EDX confirmed the presence of oxycellulose in the nanofibers. • Nanofibers modified with calcium salt of oxycellulose exhibited significant antibacterial properties. • Nanofibers modified with sodium salt of oxycellulose revealed excellent biocompatibility with cell line NCI-H441.

  9. Physicochemical investigations of carbon nanofiber supported Cu/ZrO2 catalyst

    International Nuclear Information System (INIS)

    Din, Israf Ud; Shaharun, Maizatul S.; Subbarao, Duvvuri; Naeem, A.

    2014-01-01

    Zirconia-promoted copper/carbon nanofiber catalysts (Cu‐ZrO 2 /CNF) were prepared by the sequential deposition precipitation method. The Herringbone type of carbon nanofiber GNF-100 (Graphite nanofiber) was used as a catalyst support. Carbon nanofiber was oxidized to (CNF-O) with 5% and 65 % concentration of nitric acid (HNO 3 ). The CNF activated with 5% HNO 3 produced higher surface area which is 155 m 2 /g. The catalyst was characterized by X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) and N 2 adsorption-desorption. The results showed that increase of HNO 3 concentration reduced the surface area and porosity of the catalyst

  10. Morphology study of nanofibers produced by extraction from polymer blend fibers using image processing

    International Nuclear Information System (INIS)

    Dehghan, Neda; Tavanaie, Mohammad Ali; Payvandy, Pedram

    2015-01-01

    The morphology of nanofibers extracted from the industrial-scale produced polypropylene/polybutylene terephthalate (PP/PBT) blend fibers was studied. To study the morphology and diameter measurements of the nanofibers, image processing method was used, and the results were compared with the results of a conventional visual method. Comparing these two methods indicated the good performance of image processing methods for the measuring of nanofiber diameter. Among the various applied image processing methods, the fuzzy c-means (FCM) method was determined as the best for image thresholding. Additionally, the distance transform method was determined as the best way for measuring nanofiber diameter. According to high regression coefficient (R=0.98) resulting between the draw ratio and nanofibers diameter, the high effectiveness of draw ratio to nanofiber diameter is concluded. The spherical (drop) shapes of the PBT dispersed phase particles were eventually deformed into very thin fibrils during the drawing process. The results of measuring the nanofiber diameters showed that the diameter means of nanofibers varied from 420 nm to 175 nm with the highest draw ratio. Good uniformity for diameter of nanofibers was observed, which had not been observed in previous works.

  11. Thermal and Electrical Characterization of the Carbon Nanofibers Based Cement Composites

    Directory of Open Access Journals (Sweden)

    Agnieszka ŚLOSARCZYK

    2017-08-01

    Full Text Available The paper describes the influence of chemical modification of vapor grown carbon nanofibers (VGCnFs on the thermal and electrical properties of the cement composites. The surface modification of nanofibers was performed by means of ozone and nitric acid treatments. It was shown that the oxidized carbon nanofibers surface plays an important role in shaping the mechanical and especially electrical properties of cement composite. For cement matrix modified with carbon nanofibers subjected to oxidized treatment, the slightly increase of cement paste resistivity was observed. It confirms the better adhesion of carbon nanofibers to cement paste. However, independently of carbon nanofibers modification, the occurrence of VGCnFs in cement paste increased the electrical conductivity of the composite in comparison to the cement paste without fibers. The obtained values of electrical resistivity were comparable with values of cement composites modified with 4 mm long carbon fibers. Moreover, it was shown that the chemical modification of carbon nanofibers surface does not influence on the thermal properties of cement composites. In case of cement paste with unmodified and modified carbon nanofibers, the Seebeck voltage was proportional to the temperature difference and was independent of the oxidation degree of carbon nanofibers.DOI: http://dx.doi.org/10.5755/j01.ms.23.2.14993

  12. (Au/PANA/PVAc) nanofibers as a novel composite matrix for albumin and streptavidin immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Golshaei, Rana [University of Kashan, Institute of Nano Science and Nano Technology, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Guler, Zeliha [Istanbul Technical University, Nanoscience and Nanoengineering, Maslak, Istanbul 34469 (Turkey); Sarac, Sezai A., E-mail: sarac@itu.edu.tr [Istanbul Technical University, Nanoscience and Nanoengineering, Maslak, Istanbul 34469 (Turkey); Istanbul Technical University, Department of Chemistry and Polymer Science and Technology, Maslak, Istanbul 34469 (Turkey)

    2016-03-01

    A novel electrospun nanofiber mat (Au/PANA/PVAc) consists of (Gold/Poly Anthranilic acid) (Au/PANA) core/shell nanostructures as a support material for protein immobilization that was developed and characterized by electrochemical impedance spectroscopy. In the core/shells, PANA served carboxyl groups (− COOH) for covalent protein immobilization and Au enhanced the electrochemical properties by acting as tiny conduction centers to facilitate electron transfer. Covalent immobilization of albumin and streptavidin as model proteins onto the (Au/PANA/PVAc) nanofibers was carried out by using 1-ethyl-3-(dimethyl-aminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxyl succinimide (NHS) activation. PVAc nanofibers were compared with Au/PANA/PVAc nanofibers before and after protein immobilization. The successful covalent binding of both albumin and streptavidin onto (Au/PANA/PVAc) nanofibers was confirmed by FTIR-ATR, Electron Microscopy/Energy-Dispersive X-ray Spectroscopy SEM/EDX and Electrochemical impedance spectroscopy (EIS). The nanofibers became resistive due to protein immobilization and the higher charge transfer resistance was observed after higher amount of protein was immobilized. - Highlights: • Au/PANA/PVAc nanofibers with (COOH) groups as a suitable supports for covalent immobilization of proteins. • Increasing of the resistivity of the nanofibers after immobilization of the proteins. • Activation of Au/PANA/PVAc nanofibers by using EDC/NHS.

  13. Electrospun water-stable zein/ethyl cellulose composite nanofiber and its drug release properties

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hangyi; Wang, Qingqing; Li, Guohui [Key Laboratory of Eco-textiles, Jiangnan University, Wuxi (China); Qiu, Yuyu [Key Laboratory of Eco-textiles, Jiangnan University, Wuxi (China); Laboratory of Natural Medicine, Wuxi Medical School, Jiangnan University (China); Wei, Qufu, E-mail: qfwei@jiangnan.edu.cn [Key Laboratory of Eco-textiles, Jiangnan University, Wuxi (China)

    2017-05-01

    A simple and cost-effective way to prepare water-stable zein-based nanofibers for potential drug delivery was presented in this article. Corn protein zein was co-electrospun with hydrophobic ethyl cellulose. Indomethacin, as a model drug, was incorporated in situ into the composite nanofibers. Scanning electron microscopy and element mapping revealed the morphologies of drug-loaded nanofibers and drug distribution, respectively. Fourier transform infrared spectra confirmed the physical blending among the components. Differential scanning calorimetry and X-ray diffraction demonstrated the physical state of drug and polymers in the nanofiber matrix. The composite nanofibers showed a sustained diffusion-controlled release according to the results of in vitro dissolution tests. - Highlights: • A simple, non-toxic and cost-effective way to improve water stability of zein nanofibers was proposed. • Electrospun zein/ethyl cellulose nanofibers with improved water stability and mechanical strength were prepared. • Indomethacin was homogeneously distributed in the zein/ethyl cellulose nanofibers with no aggregation or cluster. • The zein/ethyl cellulose nanofibers presented a sustained drug release profile, following Fickican diffusion mechanism.

  14. Synthesis and Characterization of Carbon nanofibers on Co and Cu Catalysts by Chemical Vapor Deposition

    International Nuclear Information System (INIS)

    Park, Eunsil; Kim, Jongwon; Lee, Changseop

    2014-01-01

    This study reports on the synthesis of carbon nanofibers via chemical vapor deposition using Co and Cu as catalysts. In order to investigate the suitability of their catalytic activity for the growth of nanofibers, we prepared catalysts for the synthesis of carbon nanofibers with Cobalt nitrate and Copper nitrate, and found the optimum concentration of each respective catalyst. Then we made them react with Aluminum nitrate and Ammonium Molybdate to form precipitates. The precipitates were dried at a temperature of 110 .deg. C in order to be prepared into catalyst powder. The catalyst was sparsely and thinly spread on a quartz tube boat to grow carbon nanofibers via thermal chemical vapor deposition. The characteristics of the synthesized carbon nanofibers were analyzed through SEM, EDS, XRD, Raman, XPS, and TG/DTA, and the specific surface area was measured via BET. Consequently, the characteristics of the synthesized carbon nanofibers were greatly influenced by the concentration ratio of metal catalysts. In particular, uniform carbon nanofibers of 27 nm in diameter grew when the concentration ratio of Co and Cu was 6:4 at 700 .deg. C of calcination temperature; carbon nanofibers synthesized under such conditions showed the best crystallizability, compared to carbon nanofibers synthesized with metal catalysts under different concentration ratios, and revealed 1.26 high amorphicity as well as 292 m 2 g -1 high specific surface area

  15. Fabrication of a novel aluminum surface covered by numerous high-aspect-ratio anodic alumina nanofibers

    Science.gov (United States)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

    2015-11-01

    The formation behavior of anodic alumina nanofibers via anodizing in a concentrated pyrophosphoric acid under various conditions was investigated using electrochemical measurements and SEM/TEM observations. Pyrophosphoric acid anodizing at 293 K resulted in the formation of numerous anodic alumina nanofibers on an aluminum substrate through a thin barrier oxide and honeycomb oxide with narrow walls. However, long-term anodizing led to the chemical dissolution of the alumina nanofibers. The density of the anodic alumina nanofibers decreased as the applied voltage increased in the 10-75 V range. However, active electrochemical dissolution of the aluminum substrate occurred at a higher voltage of 90 V. Low temperature anodizing at 273 K resulted in the formation of long alumina nanofibers measuring several micrometers in length, even though a long processing time was required due to the low current density during the low temperature anodizing. In contrast, high temperature anodizing easily resulted in the formation and chemical dissolution of alumina nanofibers. The structural nanofeatures of the anodic alumina nanofibers were controlled by choosing of the appropriate electrochemical conditions, and numerous high-aspect-ratio alumina nanofibers (>100) can be successfully fabricated. The anodic alumina nanofibers consisted of a pure amorphous aluminum oxide without anions from the employed electrolyte.

  16. Recent Advances in Cell Electrospining of Natural and Synthetic Nanofibers for Regenerative Medicine.

    Science.gov (United States)

    Zamani, Reza; Aval, Sedigheh Fekri; Pilehvar-Soltanahmadi, Younes; Nejati-Koshki, Kazem; Zarghami, Nosratollah

    2018-01-22

    The progression of nanotechnology provides opportunities to manipulate synthetic and natural materials to mimic the natural structure for tissue engineering applications. The electrospinning technique applies electrostatic principle to fabricate electrospun nanofibers. Nanofiber scaffolds are precisely similar to the native extracellular matrix (ECM) and support cell proliferation, adhesion, tendency to preserve their phenotypic shape and directed growth according to the nanofiber direction. This study reviewed both the natural and synthetic type of nanofibers and described the different properties used to trigger certain process in the tissue development. Also, the potential applications of electrospun scaffolds for regenerative medicine were summarized. © Georg Thieme Verlag KG Stuttgart · New York.

  17. Preparation of Fish Skin Gelatin-Based Nanofibers Incorporating Cinnamaldehyde by Solution Blow Spinning

    Science.gov (United States)

    Liu, Fei; Avena-Bustillos, Roberto J.; Bridges, David F.; Takeoka, Gary R.; Wu, Vivian C. H.; Chiou, Bor-Sen; McHugh, Tara H.; Zhong, Fang

    2018-01-01

    Cinnamaldehyde, a natural preservative that can non-specifically deactivate foodborne pathogens, was successfully incorporated into fish skin gelatin (FSG) solutions and blow spun into uniform nanofibers. The effects of cinnamaldehyde ratios (5–30%, w/w FSG) on physicochemical properties of fiber-forming emulsions (FFEs) and their nanofibers were investigated. Higher ratios resulted in higher values in particle size and viscosity of FFEs, as well as higher values in diameter of nanofibers. Loss of cinnamaldehyde was observed during solution blow spinning (SBS) process and cinnamaldehyde was mainly located on the surface of resultant nanofibers. Nanofibers all showed antibacterial activity by direct diffusion and vapor release against Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes. Inhibition zones increased as cinnamaldehyde ratio increased. Nanofibers showed larger inhibition effects than films prepared by casting method when S. typhimurium was exposed to the released cinnamaldehyde vapor, although films had higher remaining cinnamaldehyde than nanofibers after preparation. Lower temperature was favorable for cinnamaldehyde retention, and nanofibers added with 10% cinnamaldehyde ratio showed the highest retention over eight-weeks of storage. Results suggest that FSG nanofibers can be prepared by SBS as carriers for antimicrobials. PMID:29470390

  18. Spectroscopy, Manipulation and Trapping of Neutral Atoms, Molecules, and Other Particles Using Optical Nanofibers: A Review

    Science.gov (United States)

    Morrissey, Michael J.; Deasy, Kieran; Frawley, Mary; Kumar, Ravi; Prel, Eugen; Russell, Laura; Truong, Viet Giang; Chormaic, Síle Nic

    2013-01-01

    The use of tapered optical fibers, i.e., optical nanofibers, for spectroscopy and the detection of small numbers of particles, such as neutral atoms or molecules, has been gaining interest in recent years. In this review, we briefly introduce the optical nanofiber, its fabrication, and optical mode propagation within. We discuss recent progress on the integration of optical nanofibers into laser-cooled atom and vapor systems, paying particular attention to spectroscopy, cold atom cloud characterization, and optical trapping schemes. Next, a natural extension of this work to molecules is introduced. Finally, we consider several alternatives to optical nanofibers that display some advantages for specific applications. PMID:23945738

  19. Preparation of Fish Skin Gelatin-Based Nanofibers Incorporating Cinnamaldehyde by Solution Blow Spinning.

    Science.gov (United States)

    Liu, Fei; Türker Saricaoglu, Furkan; Avena-Bustillos, Roberto J; Bridges, David F; Takeoka, Gary R; Wu, Vivian C H; Chiou, Bor-Sen; Wood, Delilah F; McHugh, Tara H; Zhong, Fang

    2018-02-22

    Cinnamaldehyde, a natural preservative that can non-specifically deactivate foodborne pathogens, was successfully incorporated into fish skin gelatin (FSG) solutions and blow spun into uniform nanofibers. The effects of cinnamaldehyde ratios (5-30%, w / w FSG) on physicochemical properties of fiber-forming emulsions (FFEs) and their nanofibers were investigated. Higher ratios resulted in higher values in particle size and viscosity of FFEs, as well as higher values in diameter of nanofibers. Loss of cinnamaldehyde was observed during solution blow spinning (SBS) process and cinnamaldehyde was mainly located on the surface of resultant nanofibers. Nanofibers all showed antibacterial activity by direct diffusion and vapor release against Escherichia coli O157:H7 , Salmonella typhimurium , and Listeria monocytogenes . Inhibition zones increased as cinnamaldehyde ratio increased. Nanofibers showed larger inhibition effects than films prepared by casting method when S . typhimurium was exposed to the released cinnamaldehyde vapor, although films had higher remaining cinnamaldehyde than nanofibers after preparation. Lower temperature was favorable for cinnamaldehyde retention, and nanofibers added with 10% cinnamaldehyde ratio showed the highest retention over eight-weeks of storage. Results suggest that FSG nanofibers can be prepared by SBS as carriers for antimicrobials.

  20. Fabrication of indium sulfide nanofibers via a hydrothermal method assisted by AAO template

    International Nuclear Information System (INIS)

    Zhu Xiaoyi; Ma Junfeng; Wang Yonggang; Tao Jiantao; Zhou Jun; Zhao Zhongqiang; Xie Lijin; Tian Hua

    2006-01-01

    β-In 2 S 3 nanofibers were successfully synthesized via a hydrothermal method with AAO membrane as a template at 150 deg. C for 15 h. XRD patterns indicated the perfect crystallization of β-In 2 S 3 . SEM images showed that the β-In 2 S 3 nanofibers grew up from the channel ends of the AAO template. TEM images confirmed that the nanofibers had a high aspect ratio of ca. 40-50 and diameters of about 10 nm. The room temperature photoluminescence (PL) spectrum of the β-In 2 S 3 nanofibers indicated its potential applications in light-emission devices

  1. Process parameter and surface morphology of pineapple leaf electrospun nanofibers (PALF)

    Science.gov (United States)

    Surip, S. N.; Aziz, F. M. A.; Bonnia, N. N.; Sekak, K. A.; Zakaria, M. N.

    2017-09-01

    In recent times, nanofibers have attracted the attention of researchers due to their pronounced micro and nano structural characteristics that enable the development of advanced materials that have sophisticated applications. The production of nanofibers by the electrospinning process is influenced both by the electrostatic forces and the viscoelastic behavior of the polymer. Process parameters, like solution feed rate, applied voltage, nozzle-collector distance, and spinning environment, and material properties, like solution concentration, viscosity, surface tension, conductivity, and solvent vapor pressure, influence the structure and properties of electrospun nanofibers. Significant work has been done to characterize the properties of PALF nanofibers as a function of process and material parameters.

  2. Nanobiotechnology approach to fabricate polycaprolactone nanofibers containing solid titanium nanoparticles as future implant materials

    DEFF Research Database (Denmark)

    Sheikh, Faheem A.; Kanjwal, Muzafar Ahmed; Cha, Jaegwan

    2011-01-01

    In this study, a good combination of electrospun poly(caprolactone) nanofibers incorporated with high purity titanium nanoparticles is introduced for hard tissue engineering applications. A simple approach to utilize the colloidal properties of poly(caprolactone) and titanium nanoparticles...... nanofiber mats, they were incubated in simulated body fluid at 37 °C for 10 days. Field emission scanning electron microscopy in combination with energy-dispersive X-ray spectroscopy indicated that incorporation of titanium strongly activates precipitation of the apatite-like materials from the utilized...... simulated body fluid. Moreover, in-vivo experiments using experimental dogs revealed that nanofibers can yield good tissue regeneration on the surfaces of nanofibers....

  3. Fabrication and Characterization of Cellulose Acetate/Montmorillonite Composite Nanofibers by Electrospinning

    Directory of Open Access Journals (Sweden)

    Se Wook Kim

    2015-01-01

    Full Text Available Nanofibers composed of cellulose acetate (CA and montmorillonite (MMT were prepared by electrospinning method. MMT was first dispersed in water and mixed with an acetic acid solution of CA. The viscosity and conductivity of the CA/MMT solutions with different MMT contents were measured to compare with those of the CA solution. The CA/MMT solutions were electrospun to fabricate the CA/MMT composite nanofibers. The morphology, thermal stability, and crystalline and mechanical properties of the composite nanofibers were characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, energy dispersive X-ray spectroscopy (EDX, thermogravimetric analysis (TGA, X-ray diffraction (XRD, and tensile test. The average diameters of the CA/MMT composite nanofibers obtained by electrospinning 18 wt% CA/MMT solutions in a mixed acetic acid/water (75/25, w/w solvent ranged from 150~350 nm. The nanofiber diameter decreased with increasing MMT content. TEM indicated the coexistence of CA nanofibers. The CA/MMT composite nanofibers showed improved tensile strength compared to the CA nanofiber due to the physical protective barriers of the silicate clay layers. MMT could be incorporated into the CA nanofibers resulting in about 400% improvement in tensile strength for the CA sample containing 5 wt% MMT.

  4. Morphology study of nanofibers produced by extraction from polymer blend fibers using image processing

    Energy Technology Data Exchange (ETDEWEB)

    Dehghan, Neda; Tavanaie, Mohammad Ali; Payvandy, Pedram [University of Yazd, Yazd (Iran, Islamic Republic of)

    2015-09-15

    The morphology of nanofibers extracted from the industrial-scale produced polypropylene/polybutylene terephthalate (PP/PBT) blend fibers was studied. To study the morphology and diameter measurements of the nanofibers, image processing method was used, and the results were compared with the results of a conventional visual method. Comparing these two methods indicated the good performance of image processing methods for the measuring of nanofiber diameter. Among the various applied image processing methods, the fuzzy c-means (FCM) method was determined as the best for image thresholding. Additionally, the distance transform method was determined as the best way for measuring nanofiber diameter. According to high regression coefficient (R=0.98) resulting between the draw ratio and nanofibers diameter, the high effectiveness of draw ratio to nanofiber diameter is concluded. The spherical (drop) shapes of the PBT dispersed phase particles were eventually deformed into very thin fibrils during the drawing process. The results of measuring the nanofiber diameters showed that the diameter means of nanofibers varied from 420 nm to 175 nm with the highest draw ratio. Good uniformity for diameter of nanofibers was observed, which had not been observed in previous works.

  5. Green-Schwarz superstring: Beltrami parametrization and world-sheet supersymmetric generalization

    International Nuclear Information System (INIS)

    Binetruy, P.; Girardi, G.; Grimm, R.

    1989-06-01

    We study a generalization of the superstring theory in which both world-sheet and space-time supersymmetries are explicit. This hybrid superstring interpolates between the Green-Schwarz and the Ramond-Neveu-Schwarz formulations. We show that the Beltrami parametrization of the world-sheet provides a natural setting for the description of K-transformations already in the Green-Schwarz string. We construct the hybrid superstring action using the (1,1) supersymmetric version of the Beltrami parametrization. We discuss the generalization of k-transformations

  6. Vitamin and Mineral Supplement Fact Sheets

    Science.gov (United States)

    ... website Submit Search NIH Office of Dietary Supplements Vitamin and Mineral Supplement Fact Sheets Search the list ... Supplements: Background Information Botanical Dietary Supplements: Background Information Vitamin and Mineral Fact Sheets Botanical Supplement Fact Sheets ...

  7. Surface plasmon resonances, optical properties, and electrical conductivity thermal hystersis of silver nanofibers produced by the electrospinning technique.

    Science.gov (United States)

    Barakat, Nasser A M; Woo, Kee-Do; Kanjwal, Muzafar A; Choi, Kyung Eun; Khil, Myung Seob; Kim, Hak Yong

    2008-10-21

    In the present study, silver metal nanofibers have been successfully prepared by using the electrospinning technique. Silver nanofibers have been produced by electrospinning a sol-gel consisting of poly(vinyl alcohol) and silver nitrate. The dried nanofiber mats have been calcined at 850 degrees C in an argon atmosphere. The produced nanofibers do have distinct plasmon resonance compared with the reported silver nanoparticles. Contrary to the introduced shapes of silver nanoparticles, the nanofibers have a blue-shifted plasmon resonance at 330 nm. Moreover, the optical properties study indicated that the synthesized nanofibers have two band gap energies of 0.75 and 2.34 eV. An investigation of the electrical conductivity behavior of the obtained nanofibers shows thermal hystersis. These privileged physical features greatly widen the applications of the prepared nanofibers in various fields.

  8. Electrospun nanofiber reinforcement of dental composites with electromagnetic alignment approach

    International Nuclear Information System (INIS)

    Uyar, Tansel; Çökeliler, Dilek; Doğan, Mustafa; Koçum, Ismail Cengiz; Karatay, Okan; Denkbaş, Emir Baki

    2016-01-01

    Polymethylmethacrylate (PMMA) is commonly used as a base acrylic denture material with benefits of rapid and easy handling, however, when it is used in prosthetic dentistry, fracturing or cracking problems can be seen due to the relatively low strength issues. Besides, acrylic resin is the still prominent material for denture fabrication due to its handy and low cost features. Numerous proposed fillers that are used to produce PMMA composites, however electrospun polyvinylalcohol (PVA) nanofiber fillers for production of PMMA composite resins are not studied as much as the others. The other focus of the practice is to compare both mechanical properties and efficiency of aligned fibers versus non-aligned PVA nanofibers in PMMA based dental composites. Field-controlled electrospinning system is manufactured and provided good alignment in lab scale as one of contributions. Some novel auxiliary electrodes in controlled structure are augmented to obtain different patterns of alignment with a certain range of fiber diameters. Scanning electron microscopy is used for physical characterization to determine the range of fiber diameters. Non-woven fiber has no unique pattern due to chaotic nature of electrospinning process, but aligned fibers have round pattern or crossed lines. These produced fibers are structured as layer-by-layer form with different features, and these features are used in producing PMMA dental composites with different volume ratios. The maximum flexural strength figure shows that fiber load by weight of 0.25% w/w and above improves in the maximum level. As a result, mechanical properties of PMMA dental composites are improved by using PVA nanofibers as a filler, however the improvement was higher when aligned PVA nanofibers are used. The maximum values were 5.1 MPa (flexural strength), 0.8 GPa (elastic modulus), and 170 kJ/m 3 (toughness) in three-point bending test. In addition to the positive results of aligned and non-aligned nanofibers it was found

  9. Electrospun nanofiber reinforcement of dental composites with electromagnetic alignment approach

    Energy Technology Data Exchange (ETDEWEB)

    Uyar, Tansel [Department of Biomedical Engineering, Başkent University Bağlıca Campus, 06530 Ankara (Turkey); Çökeliler, Dilek, E-mail: cokeliler@baskent.edu.tr [Department of Biomedical Engineering, Başkent University Bağlıca Campus, 06530 Ankara (Turkey); Doğan, Mustafa [Department of Electrical and Electronics Engineering, Başkent University, Ankara 06180 (Turkey); Koçum, Ismail Cengiz [Department of Biomedical Engineering, Başkent University Bağlıca Campus, 06530 Ankara (Turkey); Karatay, Okan [Department of Electrical and Electronics Engineering, Başkent University, Ankara 06180 (Turkey); Denkbaş, Emir Baki [Department of Chemistry, Biochemistry Division, Hacettepe University, Ankara (Turkey)

    2016-05-01

    Polymethylmethacrylate (PMMA) is commonly used as a base acrylic denture material with benefits of rapid and easy handling, however, when it is used in prosthetic dentistry, fracturing or cracking problems can be seen due to the relatively low strength issues. Besides, acrylic resin is the still prominent material for denture fabrication due to its handy and low cost features. Numerous proposed fillers that are used to produce PMMA composites, however electrospun polyvinylalcohol (PVA) nanofiber fillers for production of PMMA composite resins are not studied as much as the others. The other focus of the practice is to compare both mechanical properties and efficiency of aligned fibers versus non-aligned PVA nanofibers in PMMA based dental composites. Field-controlled electrospinning system is manufactured and provided good alignment in lab scale as one of contributions. Some novel auxiliary electrodes in controlled structure are augmented to obtain different patterns of alignment with a certain range of fiber diameters. Scanning electron microscopy is used for physical characterization to determine the range of fiber diameters. Non-woven fiber has no unique pattern due to chaotic nature of electrospinning process, but aligned fibers have round pattern or crossed lines. These produced fibers are structured as layer-by-layer form with different features, and these features are used in producing PMMA dental composites with different volume ratios. The maximum flexural strength figure shows that fiber load by weight of 0.25% w/w and above improves in the maximum level. As a result, mechanical properties of PMMA dental composites are improved by using PVA nanofibers as a filler, however the improvement was higher when aligned PVA nanofibers are used. The maximum values were 5.1 MPa (flexural strength), 0.8 GPa (elastic modulus), and 170 kJ/m{sup 3} (toughness) in three-point bending test. In addition to the positive results of aligned and non-aligned nanofibers it was

  10. Extraction of cellulose nanofibers from Pinus oocarpa residues

    Energy Technology Data Exchange (ETDEWEB)

    Manrich, Anny; Martins, Maria Alice, E-mail: anny@daad-alumni.de [EMBRAPA Instrumentacao, Sao Carlos, SP (Brazil); Moraes, Jheyce Cristina; Pasquoloto, Camila [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil)

    2016-07-01

    Full text: Pinus oocarpa, which wood is moderately hard and tough, is planted in Brazil for reforestation and employed for timber production used in constructions. The wood residues, such as shavings, bark and sawdust represent 30% to 50% of the total volume of wood production, of which the sawdust is 10%{sup 1}. Cellulose nanofibers is nanomaterials having a diameter between 5 nm and 20 nm and a length of up to hundreds of nm. To obtain nanofibers from cellulose sources, such as sisal and sugarcane bagasse, is used chemical processes, in which the lignocellulosic material initially undergoes pre-treatments to promote partial separation of the cellulose, such as mercerisation and bleaching thus disposing lignin and hemicellulose components. Sequentially, by controlled acid hydrolysis, amorphous regions of the cellulose are removed, and crystalline cellulose is isolated in the form of cellulose nanofibers. In this work, nanofibers from sawdust of Pinnus oocarpa, containing 44.8 wt% of cellulose 20.6 wt% hemicellulose and 30.0 wt% insoluble lignin were isolated by mercerisation (NaOH 5%, 80°C, 120 min), followed by bleaching (NaOH + acetic acid + NaClO{sub 2}, 80 deg C, 240min) and acid hydrolysis (60 wt% sulfuric acid, 45 °C, 40min). Nanofibers obtained were characterized by DRX and SEM-FEG. Results showed that, for used conditions, fiber acid hydrolysis was not complete, therefore a biphasic suspension was formed. Crystallinity index achieved was not much higher than that from pinus fiber itself, increasing from 62% to 65% and signs of cellulose type II were observed. SEM images showed elongated fibers, which have diameter of 15 ± 5 nm and length of hundreds of nm, what means that they have a large L/D aspect ratio. Nanofiber extraction yield was very low (1.3 wt% of initial residue). All steps of the process are being reviewed aiming at better results. 1) Morais, S. A. L.; Nascimento E. A. e D. C. Melo, 2005, R. Árvore, 29, 3, 461-470. (author)

  11. Resin infusion of layered metal/composite hybrid and resulting metal/composite hybrid laminate

    Science.gov (United States)

    Cano, Roberto J. (Inventor); Grimsley, Brian W. (Inventor); Weiser, Erik S. (Inventor); Jensen, Brian J. (Inventor)

    2009-01-01

    A method of fabricating a metal/composite hybrid laminate is provided. One or more layered arrangements are stacked on a solid base to form a layered structure. Each layered arrangement is defined by a fibrous material and a perforated metal sheet. A resin in its liquid state is introduced along a portion of the layered structure while a differential pressure is applied across the laminate structure until the resin permeates the fibrous material of each layered arrangement and fills perforations in each perforated metal sheet. The resin is cured thereby yielding a metal/composite hybrid laminate.

  12. Selectively reflective transparent sheets

    Science.gov (United States)

    Waché, Rémi; Florescu, Marian; Sweeney, Stephen J.; Clowes, Steven K.

    2015-08-01

    We investigate the possibility to selectively reflect certain wavelengths while maintaining the optical properties on other spectral ranges. This is of particular interest for transparent materials, which for specific applications may require high reflectivity at pre-determined frequencies. Although there exist currently techniques such as coatings to produce selective reflection, this work focuses on new approaches for mass production of polyethylene sheets which incorporate either additives or surface patterning for selective reflection between 8 to 13 μ m. Typical additives used to produce a greenhouse effect in plastics include particles such as clays, silica or hydroxide materials. However, the absorption of thermal radiation is less efficient than the decrease of emissivity as it can be compared with the inclusion of Lambertian materials. Photonic band gap engineering by the periodic structuring of metamaterials is known in nature for producing the vivid bright colors in certain organisms via strong wavelength-selective reflection. Research to artificially engineer such structures has mainly focused on wavelengths in the visible and near infrared. However few studies to date have been carried out to investigate the properties of metastructures in the mid infrared range even though the patterning of microstructure is easier to achieve. We present preliminary results on the diffuse reflectivity using FDTD simulations and analyze the technical feasibility of these approaches.

  13. Superfund fact sheet: The remedial program. Fact sheet

    International Nuclear Information System (INIS)

    1992-09-01

    The fact sheet describes what various actions the EPA can take to clean up hazardous wastes sites. Explanations of how the criteria for environmental and public health risk assessment are determined and the role of state and local governments in site remediation are given. The fact sheet is one in a series providing reference information about Superfund issues and is intended for readers with no formal scientific training

  14. A novel nano-nonwoven fabric with three-dimensionally dispersed nanofibers: entrapment of carbon nanofibers within nonwovens using the wet-lay process

    International Nuclear Information System (INIS)

    Karwa, Amogh N; Davis, Virginia A; Tatarchuk, Bruce J; Barron, Troy J

    2012-01-01

    This study demonstrates, for the first time, the manufacturing of novel nano-nonwovens that are comprised of three-dimensionally distributed carbon nanofibers within the matrices of traditional wet-laid nonwovens. The preparation of these nano-nonwovens involves dispersing and flocking carbon nanofibers, and optimizing colloidal chemistry during wet-lay formation. The distribution of nanofibers within the nano-nonwoven was verified using polydispersed aerosol filtration testing, air permeability, low surface tension liquid capillary porometry, SEM and cyclic voltammetry. All these characterization techniques indicated that nanofiber flocks did not behave as large solid clumps, but retained the ‘nanoporous’ structure expected from nanofibers. These nano-nonwovens showed significant enhancements in aerosol filtration performance. The reduction–oxidation reactions of the functional groups on nanofibers and the linear variation of electric double-layer capacitance with nanofiber loading were measured using cyclic voltammetry. More than 65 m 2 (700 ft 2 ) of the composite were made during the demonstration of process scalability using a Fourdrinier-type continuous pilot papermaking machine. The scalability of the process with the control over pore size distribution makes these composites very promising for filtration and other nonwoven applications. (paper)

  15. Polyvinyl alcohol/starch composite nanofibers by bubble electrospinning

    Directory of Open Access Journals (Sweden)

    Liu Zhi

    2014-01-01

    Full Text Available Bubble electrospinning exhibits profound prospect of industrialization of macro/ nano materials. Starch is the most abundant and inexpensive biopolymer. With the drawbacks of poor strength, water resistibility, thermal stability and processability of pure starch, some biodegradable synthetic polymers such as poly (lactic acid, polyvinyl alcohol were composited to electrospinning. To the best of our knowledge, composite nanofibers of polyvinyl alcohol/starch from bubble electrospinning have never been investigated. In the present study, nanofibers of polyvinyl alcohol/starch were prepared from bubble electrospinning. The processability and the morphology were affected by the weight ratio of polyvinyl alcohol and starchy. The rheological studies were in agreement with the spinnability of the electrospinning solutions.

  16. Vertically Aligned Carbon Nanofiber based Biosensor Platform for Glucose Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Al Mamun, Khandaker A.; Tulip, Fahmida S.; MacArthur, Kimberly; McFarlane, Nicole; Islam, Syed K.; Hensley, Dale

    2014-03-01

    Vertically aligned carbon nanofibers (VACNFs) have recently become an important tool for biosensor design. Carbon nanofibers (CNF) have excellent conductive and structural properties with many irregularities and defect sites in addition to exposed carboxyl groups throughout their surfaces. These properties allow a better immobilization matrix compared to carbon nanotubes and offer better resolution when compared with the FET-based biosensors. VACNFs can be deterministically grown on silicon substrates allowing optimization of the structures for various biosensor applications. Two VACNF electrode architectures have been employed in this study and a comparison of their performances has been made in terms of sensitivity, sensing limitations, dynamic range, and response time. The usage of VACNF platform as a glucose sensor has been verified in this study by selecting an optimum architecture based on the VACNF forest density. Read More: http://www.worldscientific.com/doi/abs/10.1142/S0129156414500062

  17. The photophysics of luminescence in multilayered organic nanofibers

    DEFF Research Database (Denmark)

    Tavares, Luciana; Quochi, Francesco; Simbrunner, Clemens

    different organic molecules (para-hexaphenyl (p6P) donor and α-sexithiophene (6T) acceptor materials). The excited donor (p6P) is able to sensitize the acceptor (6T) via resonance energy transfer (Förster) as a consequence of the overlap between the p6P photo emission spectrum and the 6T absorption spectrum......Multilayered crystalline nanofibers are exemplary model system for the study of exciton dynamics and lasing in organic materials due to their well-defined morphology, high luminescence efficiencies, and color tunability. The multi-layered nanofibers are composed of alternating layers of two...... to extract the activation energy for exciton diffusion in crystalline p6P (19 meV). The weak PL temperature dependence of the acceptor material (6T) and hence its high quantum yield in combination with the small activation energy for exciton diffusion of the donor material (p6P) explain the high efficiency...

  18. Quasi one dimensional transport in individual electrospun composite nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Avnon, A., E-mail: avnon@phys.fu-berlin.de; Datsyuk, V.; Trotsenko, S. [Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany); Wang, B.; Zhou, S. [Research Center of Microperipheric Technologies, Technische Universität Berlin, TiB4/2-1, Gustav-Meyer-Allee 25, 13355 Berlin (Germany); Grabbert, N.; Ngo, H.-D. [Microsystem Engineering (FB I), University of Applied Sciences, Wilhelminenhofstr. 74 (C 525), 12459 Berlin (Germany)

    2014-01-15

    We present results of transport measurements of individual suspended electrospun nanofibers Poly(methyl methacrylate)-multiwalled carbon nanotubes. The nanofiber is comprised of highly aligned consecutive multiwalled carbon nanotubes. We have confirmed that at the range temperature from room temperature down to ∼60 K, the conductance behaves as power-law of temperature with an exponent of α ∼ 2.9−10.2. The current also behaves as power law of voltage with an exponent of β ∼ 2.3−8.6. The power-law behavior is a footprint for one dimensional transport. The possible models of this confined system are discussed. Using the model of Luttinger liquid states in series, we calculated the exponent for tunneling into the bulk of a single multiwalled carbon nanotube α{sub bulk} ∼ 0.06 which agrees with theoretical predictions.

  19. Carbon composites composites with carbon fibers, nanofibers, and nanotubes

    CERN Document Server

    Chung, Deborah D L

    2017-01-01

    Carbon Composites: Composites with Carbon Fibers, Nanofibers, and Nanotubes, Second Edition, provides the reader with information on a wide range of carbon fiber composites, including polymer-matrix, metal-matrix, carbon-matrix, ceramic-matrix and cement-matrix composites. In contrast to other books on composites, this work emphasizes materials rather than mechanics. This emphasis reflects the key role of materials science and engineering in the development of composite materials. The applications focus of the book covers both the developing range of structural applications for carbon fiber composites, including military and civil aircraft, automobiles and construction, and non-structural applications, including electromagnetic shielding, sensing/monitoring, vibration damping, energy storage, energy generation, and deicing. In addition to these new application areas, new material in this updated edition includes coverage of cement-matrix composites, carbon nanofibers, carbon matrix precursors, fiber surface ...

  20. Electrospun Ceramic Nanofiber Mats Today: Synthesis, Properties, and Applications

    Science.gov (United States)

    Esfahani, Hamid; Ramakrishna, Seeram

    2017-01-01

    Ceramic nanofibers (NFs) have recently been developed for advanced applications due to their unique properties. In this article, we review developments in electrospun ceramic NFs with regard to their fabrication process, properties, and applications. We find that surface activity of electrospun ceramic NFs is improved by post pyrolysis, hydrothermal, and carbothermal processes. Also, when combined with another surface modification methods, electrospun ceramic NFs result in the advancement of properties and widening of the application domains. With the decrease in diameter and length of a fiber, many properties of fibrous materials are modified; characteristics of such ceramic NFs are different from their wide and long (bulk) counterparts. In this article, electrospun ceramic NFs are reviewed with an emphasis on their applications as catalysts, membranes, sensors, biomaterials, fuel cells, batteries, supercapacitors, energy harvesting systems, electric and magnetic parts, conductive wires, and wearable electronic textiles. Furthermore, properties of ceramic nanofibers, which enable the above applications, and techniques to characterize them are briefly outlined. PMID:29077074

  1. Electrospun Ceramic Nanofiber Mats Today: Synthesis, Properties, and Applications

    Directory of Open Access Journals (Sweden)

    Hamid Esfahani

    2017-10-01

    Full Text Available Ceramic nanofibers (NFs have recently been developed for advanced applications due to their unique properties. In this article, we review developments in electrospun ceramic NFs with regard to their fabrication process, properties, and applications. We find that surface activity of electrospun ceramic NFs is improved by post pyrolysis, hydrothermal, and carbothermal processes. Also, when combined with another surface modification methods, electrospun ceramic NFs result in the advancement of properties and widening of the application domains. With the decrease in diameter and length of a fiber, many properties of fibrous materials are modified; characteristics of such ceramic NFs are different from their wide and long (bulk counterparts. In this article, electrospun ceramic NFs are reviewed with an emphasis on their applications as catalysts, membranes, sensors, biomaterials, fuel cells, batteries, supercapacitors, energy harvesting systems, electric and magnetic parts, conductive wires, and wearable electronic textiles. Furthermore, properties of ceramic nanofibers, which enable the above applications, and techniques to characterize them are briefly outlined.

  2. Polyurethane Nanofiber Membranes for Waste Water Treatment by Membrane Distillation

    Directory of Open Access Journals (Sweden)

    T. Jiříček

    2017-01-01

    Full Text Available Self-sustained electrospun polyurethane nanofiber membranes were manufactured and tested on a direct-contact membrane distillation unit in an effort to find the optimum membrane thickness to maximize flux rate and minimize heat losses across the membrane. Also salt retention and flux at high salinities up to 100 g kg−1 were evaluated. Even though the complex structure of nanofiber layers has extreme specific surface and porosity, membrane performance was surprisingly predictable; the highest flux was achieved with the thinnest membranes and the best energy efficiency was achieved with the thickest membranes. All membranes had salt retention above 99%. Nanotechnology offers the potential to find modern solutions for desalination of waste waters, by introducing new materials with revolutionary properties, but new membranes must be developed according to the target application.

  3. Ethylene tetrafluoroethylene nanofibers prepared by CO2 laser supersonic drawing

    Directory of Open Access Journals (Sweden)

    A. Suzuki

    2013-06-01

    Full Text Available Ethylene tetrafluoroethylene (ETFE nanofibers were prepared by carbon dioxide (CO2 laser irradiation of asspun ETFE fibers with four different melt flow rates (MFRs in a supersonic jet that was generated by blowing air into a vacuum chamber through the fiber injection orifice. The drawability and superstructure of fibers produced by CO2 laser supersonic drawing depend on the laser power, the chamber pressure, the fiber injection speed, and the MFR. Nanofibers obtained using a laser power of 20 W, a chamber pressure of 20 kPa, and an MFR of 308 g•10 min–1 had an average diameter of 0.303 µm and a degree of crystallinity of 54%.

  4. 2012 Swimming Season Fact Sheets

    Science.gov (United States)

    To help beachgoers make informed decisions about swimming at U.S. beaches, EPA annually publishes state-by-state data about beach closings and advisories for the previous year's swimming season. These fact sheets summarize that information by state.

  5. State Fact Sheets on COPD

    Science.gov (United States)

    ... Submit Search The CDC Chronic Obstructive Pulmonary Disease (COPD) Note: Javascript is disabled or is not supported ... message, please visit this page: About CDC.gov . COPD Homepage Data and Statistics Fact Sheets Publications Publications ...

  6. Fabrication of PEDOT coated PVA-GO nanofiber for supercapacitor

    International Nuclear Information System (INIS)

    Mohd Abdah, Muhammad Amirul Aizat; Zubair, Nur Afifah; Azman, Nur Hawa Nabilah; Sulaiman, Yusran

    2017-01-01

    Conducting nanofibers comprised of poly(vinyl alcohol) (PVA)-graphene oxide (GO) nanofiber coated with poly(3,4-ethylenedioxythiophene) (PEDOT) for supercapacitor application was prepared through integrated techniques i.e. electrospinning and electrodeposition. The formation of smooth cross-linking nanofibers without beads proved that GO has uniformly distributed into PVA with an average diameter of 117 ± 32 nm. Field emission scanning electron microscopy (FESEM) images revealed that cauliflower-like structure of PEDOT grew well on the surface of PVA-GO nanofibers with high porosity. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy proved the existence of PVA, GO, and PEDOT. PVA-GO/PEDOT nanocomposite showed the highest specific capacitance (224.27 F/g) compared to PEDOT (167.92 F/g) and PVA/PEDOT (182.73 F/g). PVA-GO/PEDOT nanocomposite exhibited 1.8 V wide operating potential windows which significantly can enhance its capacitive behaviour. PVA-GO/PEDOT nanocomposite has also demonstrated superior performance with the energy density and power density of 9.58 Wh/kg and 304.37 W/kg, respectively at 1.0 A/g current density. PVA-GO/PEDOT nanocomposite revealed the smallest resistance of charge transfer (R_c_t) and equivalent series resistance (ESR) indicating excellent charge propagation behaviour at the interfacial region. The composite exhibits a good capacity retention of 82.41% after 2000 CV cycles and further drops 11.27% after 5000 cycles caused by the swelling and shrinkage of the electrode material during the charging and discharging processes. - Highlights: • PVA-GO/PEDOT was prepared via electrospinning and electrodeposition. • PVA-GO/PEDOT displays high capacitance value with wide potential window of 1.8 V. • PVA-GO/PEDOT exhibits high energy and power density, low R_c_t and ESR.

  7. Tuneable nanoparticle-nanofiber composite substrate for improved cellular adhesion.

    Science.gov (United States)

    Nicolini, Ariana M; Toth, Tyler D; Yoon, Jeong-Yeol

    2016-09-01

    This work presents a novel technique using a reverse potential electrospinning mode for fabricating nanoparticle-embedded composites that can be tailored to represent various fiber diameters, surface morphologies, and functional groups necessary for improved cellular adhesion. Polycaprolactone (PCL) nanofibers were electrospun in both traditional positive (PP) and reverse potential (RP) electrical fields. The fibers were incorporated with 300nm polystyrene (PS) fluorescent particles, which contained carboxyl, amine groups, and surfactants. In the unconventional RP, the charged colloidal particles and surfactants were shown to have an exaggerated effect on Taylor cone morphology and fiber diameter caused by the changes in charge density and surface tension of the bulk solution. The RP mode was shown to lead to a decrease in fiber diameter from 1200±100nm (diameter±SE) for the nanofibers made with PCL alone to 440±80nm with the incorporation of colloidal particles, compared to the PP mode ranging from 530±90nm to 350±50nm, respectively. The nanoparticle-nanofiber composite substrates were cultured with human umbilical vein endothelial cells (HUVECs) and evaluated for cellular viability and adhesion for up to 5 days. Adhesion to the nanofibrous substrates was improved by 180±10% with the addition of carboxylated particles and by 480±60% with the functionalization of an RGD ligand compared to the PCL nanofibers. The novel approach of electrospinning in the RP mode with the addition of colloids in order to alter charge density and surface tension could be utilized towards many applications, one being implantable biomaterials and tissue engineered scaffolds as demonstrated in this work. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Nanoscaled Mechanical Properties of Cement Composites Reinforced with Carbon Nanofibers

    OpenAIRE

    Barbhuiya, Salim; Chow, PengLoy

    2017-01-01

    This paper reports the effects of carbon nanofibers (CNFs) on nanoscaled mechanical properties of cement composites. CNFs were added to cement composites at the filler loading of 0.2 wt % (by wt. of cement). Micrographs based on scanning electron microscopy (SEM) show that CNFs are capable of forming strong interfacial bonding with cement matrices. Experimental results using nanoindentation reveal that the addition of CNFs in cement composites increases the proportions of high-density calcium...

  9. Fabrication of PEDOT coated PVA-GO nanofiber for supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Mohd Abdah, Muhammad Amirul Aizat; Zubair, Nur Afifah; Azman, Nur Hawa Nabilah [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia); Sulaiman, Yusran, E-mail: yusran@upm.edu.my [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia); Functional Device Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia)

    2017-05-01

    Conducting nanofibers comprised of poly(vinyl alcohol) (PVA)-graphene oxide (GO) nanofiber coated with poly(3,4-ethylenedioxythiophene) (PEDOT) for supercapacitor application was prepared through integrated techniques i.e. electrospinning and electrodeposition. The formation of smooth cross-linking nanofibers without beads proved that GO has uniformly distributed into PVA with an average diameter of 117 ± 32 nm. Field emission scanning electron microscopy (FESEM) images revealed that cauliflower-like structure of PEDOT grew well on the surface of PVA-GO nanofibers with high porosity. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy proved the existence of PVA, GO, and PEDOT. PVA-GO/PEDOT nanocomposite showed the highest specific capacitance (224.27 F/g) compared to PEDOT (167.92 F/g) and PVA/PEDOT (182.73 F/g). PVA-GO/PEDOT nanocomposite exhibited 1.8 V wide operating potential windows which significantly can enhance its capacitive behaviour. PVA-GO/PEDOT nanocomposite has also demonstrated superior performance with the energy density and power density of 9.58 Wh/kg and 304.37 W/kg, respectively at 1.0 A/g current density. PVA-GO/PEDOT nanocomposite revealed the smallest resistance of charge transfer (R{sub ct}) and equivalent series resistance (ESR) indicating excellent charge propagation behaviour at the interfacial region. The composite exhibits a good capacity retention of 82.41% after 2000 CV cycles and further drops 11.27% after 5000 cycles caused by the swelling and shrinkage of the electrode material during the charging and discharging processes. - Highlights: • PVA-GO/PEDOT was prepared via electrospinning and electrodeposition. • PVA-GO/PEDOT displays high capacitance value with wide potential window of 1.8 V. • PVA-GO/PEDOT exhibits high energy and power density, low R{sub ct} and ESR.

  10. Multifunctional Composite Nanofibers for Smart Structures

    Science.gov (United States)

    2011-10-13

    such as the Shape Memory Alloy (SMA) and/or shape memory polymer (SMP) and other hybrid systems. We specifically attempt to answer the following...stress induced from SiNP expansion upon alloying with Li ions. The cycling performance of core-shell CNF/SiNP composite is compared with that of non...Ayranci, Frank Ko, Tucker Howie, MinoruTaya, “Shape memory effect of a thermoset polymer and its fiber reinforced composites, submitted to the 18th

  11. Cellulose nanofibers use in coated paper

    Science.gov (United States)

    Richmond, Finley

    Cellulose Nanofibers (CNF) are materials that can be obtained by the mechanical breakdown of natural fibers. CNF have the potential to be produced at low cost in a paper mill and may provide novel properties to paper, paper coatings, paints, or other products. However, suspensions have a complex rheology even at low solid contents. To be able to coat, pump, or mix CNF at moderate solids, it is critical to understand the rheology of these suspensions and how they flow in process equipment; current papers only report the rheology up to 6% solids. Few publications are available that describe the coating of CNF onto paper or the use of CNF as an additive into a paper coating. The rheology of CNF suspensions and coatings that contain CNF were characterized with parallel-disk geometry in a controlled stress rheometer. The steady shear viscosity, the complex viscosity, the storage modulus, and the yield stress were determined for the range of solids or concentrations (2.5-10.5%). CNF were coated onto paper with a laboratory rod coater, a size press and a high speed cylindrical laboratory coater (CLC). For each case, the coat weights were measures and the properties of the papers were characterized. CNF water base suspension was found to be a shear thinning with a power law index of around 0.1. Oscillatory tests showed a linear viscoelastic region at low strains and significant storage and loss moduli even at low solids. The Cox Merz rule does not hold for CNF suspensions or coating formulations that contain CNF with complex viscosities that are about 100 times larger than the steady shear viscosities. Paper coating formulations that contain CNF were found to have viscosities and storage and loss moduli that are over ten times larger than coatings that contain starch at similar solids. CNF suspensions were coated on papers with low amount transferred on paper either at high solids or high nip loadings. The amount transferred appears to be controlled by an interaction of

  12. Australian Government Balance Sheet Management

    OpenAIRE

    Wilson Au-Yeung; Jason McDonald; Amanda Sayegh

    2006-01-01

    Since almost eliminating net debt, the Australian Government%u2019s attention has turned to the financing of broader balance sheet liabilities, such as public sector superannuation. Australia will be developing a significant financial asset portfolio in the %u2018Future Fund%u2019 to smooth the financing of expenses through time. This raises the significant policy question of how best to manage the government balance sheet to reduce risk. This paper provides a framework for optimal balance sh...

  13. Energy information sheets, July 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the public. The Energy Information Sheets was developed to provide general information on various aspects of fuel production, prices, consumption, and capability. Additional information on related subject matter can be found in other Energy Information Administration (EIA) publications as referenced at the end of each sheet.

  14. Energy information sheets, September 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the public. The Energy Information Sheets was developed to provide general information on various aspects of fuel production, prices, consumption, and capability. Additional information on related subject matter can be found in other Energy Information Administration (EIA) publications as referenced at the end of each sheet.

  15. Laser-induced charge separation in organic nanofibers

    DEFF Research Database (Denmark)

    Tavares, Luciana; Behn, Dino; Kjelstrup-Hansen, Jakob

    Organic semiconductors have unique properties that can be tailored via synthetic chemistry for specific applications, which combined with their low price and straight-forward processing over large areas make them interesting materials for future devices. Certain oligomers can self-assemble into c......Organic semiconductors have unique properties that can be tailored via synthetic chemistry for specific applications, which combined with their low price and straight-forward processing over large areas make them interesting materials for future devices. Certain oligomers can self......-assemble into crystalline nanofibers by vapor deposition onto muscovite mica substrates, and we have recently shown that such nanofibers can be transferred to different substrates by roll-printing and used as the active material in e.g. organic field-effect transistors (OFETs), organic light-emitting transistors (OLETs......), and organic phototransistors (OPTs). However, several device-related issues incl. charge-separation and local band structure remain poorly understood. In this work, we use electrostatic force microscopy (EFM) combined with optical microscopy to study the local surface charge of an individual organic nanofiber...

  16. Proliferation of Genetically Modified Human Cells on Electrospun Nanofiber Scaffolds

    Directory of Open Access Journals (Sweden)

    Mandula Borjigin

    2012-01-01

    Full Text Available Gene editing is a process by which single base mutations can be corrected, in the context of the chromosome, using single-stranded oligodeoxynucleotides (ssODNs. The survival and proliferation of the corrected cells bearing modified genes, however, are impeded by a phenomenon known as reduced proliferation phenotype (RPP; this is a barrier to practical implementation. To overcome the RPP problem, we utilized nanofiber scaffolds as templates on which modified cells were allowed to recover, grow, and expand after gene editing. Here, we present evidence that some HCT116-19, bearing an integrated, mutated enhanced green fluorescent protein (eGFP gene and corrected by gene editing, proliferate on polylysine or fibronectin-coated polycaprolactone (PCL nanofiber scaffolds. In contrast, no cells from the same reaction protocol plated on both regular dish surfaces and polylysine (or fibronectin-coated dish surfaces proliferate. Therefore, growing genetically modified (edited cells on electrospun nanofiber scaffolds promotes the reversal of the RPP and increases the potential of gene editing as an ex vivo gene therapy application.

  17. Light-activated polymethylmethacrylate nanofibers with antibacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Elashnikov, Roman [Department of Solid State Engineering, University of Chemistry and Technology, 16628 Prague (Czech Republic); Lyutakov, Oleksiy, E-mail: lyutakoo@vscht.cz [Department of Solid State Engineering, University of Chemistry and Technology, 16628 Prague (Czech Republic); Ulbrich, Pavel [Department of Biochemistry and Microbiology, University of Chemistry and Technology, 16628 Prague (Czech Republic); Svorcik, Vaclav [Department of Solid State Engineering, University of Chemistry and Technology, 16628 Prague (Czech Republic)

    2016-07-01

    The creation of an antibacterial material with triggerable properties enables us to avoid the overuse or misuse of antibacterial substances and, thus, prevent the emergence of resistant bacterial strains. As a potential light-activated antibacterial material, polymethylmethacrylate (PMMA) nanofibers doped with silver nanoparticles (AgNPs) and meso-tetraphenylporphyrin (TPP) were prepared by electrospinning. TPP was chosen as an effectively reactive oxygen species (ROS) producer. Antibacterial tests on Staphylococcus epidermidis (S. epidermidis) and Enterococcus faecalis (E. faecalis) showed the excellent light-triggerable antibacterial activity of the doped materials. Upon light irradiation at the wavelength corresponding to the TPP absorption peak (405 nm), antibacterial activity dramatically increased, mostly due to the release of AgNPs from the polymer matrix. Furthermore, under prolonged light irradiation, the AgNPs/TPP/PMMA nanofibers, displayed enhanced longevity and photothermal stability. Thus, our results suggest that the proposed material is a promising option for the photodynamic inactivation of bacteria. - Highlights: • The novelty of proposed work can be summared as follow: • Silver nanoparticles/meso-tetraphenylporphyrin embedded polymethylmethacrylate nanofibers were obtained for the first time. • Light triggering of PMMA fibers leads to sufficient release of AgNPs or their agglomeration, depending on the light source. • Release of AgNPs leads to appearance of pronounced antimicrobial activity, which can be switched on/off by the illumination.

  18. Preparation and Characterization of Gelatin Nanofibers Containing Silver Nanoparticles

    Science.gov (United States)

    Jeong, Lim; Park, Won Ho

    2014-01-01

    Ag nanoparticles (NPs) were synthesized in formic acid aqueous solutions through chemical reduction. Formic acid was used for a reducing agent of Ag precursor and solvent of gelatin. Silver acetate, silver tetrafluoroborate, silver nitrate, and silver phosphate were used as Ag precursors. Ag+ ions were reduced into Ag NPs by formic acid. The formation of Ag NPs was characterized by a UV-Vis spectrophotometer. Ag NPs were quickly generated within a few minutes in silver nitrate (AgNO3)/formic acid solution. As the water content of formic acid aqueous solution increased, more Ag NPs were generated, at a higher rate and with greater size. When gelatin was added to the AgNO3/formic acid solution, the Ag NPs were stabilized, resulting in smaller particles. Moreover, gelatin limits further aggregation of Ag NPs, which were effectively dispersed in solution. The amount of Ag NPs formed increased with increasing concentration of AgNO3 and aging time. Gelatin nanofibers containing Ag NPs were fabricated by electrospinning. The average diameters of gelatin nanofibers were 166.52 ± 32.72 nm, but these decreased with the addition of AgNO3. The average diameters of the Ag NPs in gelatin nanofibers ranged between 13 and 25 nm, which was confirmed by transmission electron microscopy (TEM). PMID:24758929

  19. Studies on electrospun nylon-6/chitosan complex nanofiber interactions

    International Nuclear Information System (INIS)

    Zhang Haitao; Li Shubai; Branford White, Christopher J.; Ning Xin; Nie Huali; Zhu Limin

    2009-01-01

    Composite membranes of nylon-6/chitosan nanofibers with different weight ratio of nylon-6 to chitosan were fabricated successfully using electrospinning. Morphologies of the nanofibers were investigated by scanning electron microscopy (SEM) and the intermolecular interactions of the nylon-6/chitosan complex were evaluated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) as well as mechanical testing. We found that morphology and diameter of the nanofibers were influenced by the concentration of the solution and weight ratio of the blending component materials. Furthermore FT-IR analyses on interactions between components demonstrated an IR band frequency shift that appeared to be dependent on the amount of chitosan in the complex. Observations from XRD and DSC suggested that a new fraction of γ phase crystals appeared and increased with the increasing content of chitosan in blends, this indicated that intermolecular interactions occurred between nylon-6 and chitosan. Results from performance data in mechanical showed that intermolecular interactions varied with varying chitosan content in the fibers. It was concluded that a new composite product was created and the stability of this system was attributed to strong new interactions such as hydrogen bond formation between the nylon-6 polymers and chitosan structures.

  20. Flexible piezoelectric nanogenerators based on PVDF-TrFE nanofibers

    Science.gov (United States)

    Serairi, Linda; Gu, Long; Qin, Yong; Lu, Yingxian; Basset, Philippe; Leprince-Wang, Yamin

    2018-01-01

    In this paper, electrospun piezoelectric PVDF-TrFE nanofibers were used for the fabrication of two types of flexible nanogenerator (NG) devices based on the direct piezoelectric effect, allowing the conversion of mechanical energy into electrical energy. The first one is composed of quite well aligned thin film nanofibers of about 35 μm and the second one is composed of random nanofibers of about 50 μm. The influence of the applied stress and strain rate on the output for both types of NG was studied. It is shown that the pulse peaks generated by NG increase with the applied mechanical strain frequency, the generated output is also proportional to the applied stress amplitude. The first NG loaded in bending mode can generate a maximum voltage of 270 mV. By connecting two devices in series/parallel, the voltage/current value could be multiplied by two. The second NG which was biased in compression mode using a shaker controlled by a force sensor, can generate a potential of about 7 V under 3.6 N applied force.

  1. Carbon nanofibers grafted on activated carbon as an electrode in high-power supercapacitors.

    Science.gov (United States)

    Gryglewicz, Grażyna; Śliwak, Agata; Béguin, François

    2013-08-01

    A hybrid electrode material for high-power supercapacitors was fabricated by grafting carbon nanofibers (CNFs) onto the surface of powdered activated carbon (AC) through catalytic chemical vapor deposition (CCVD). A uniform thin layer of disentangled CNFs with a herringbone structure was deposited on the carbon surface through the decomposition of propane at 450 °C over an AC-supported nickel catalyst. CNF coating was controlled by the reaction time and the nickel content. The superior CNF/AC composite displays excellent electrochemical performance in a 0.5 mol L(-1) solution of K2 SO4 due to its unique structure. At a high scan rate (100 mV s(-1) ) and current loading (20 A g(-1) ), the capacitance values were three- and fourfold higher than those for classical AC/carbon black composites. Owing to this feature, a high energy of 10 Wh kg(-1) was obtained over a wide power range in neutral medium at a voltage of 0.8 V. The significant enhancement of charge propagation is attributed to the presence of herringbone CNFs, which facilitate the diffusion of ions in the electrode and play the role of electronic bridges between AC particles. An in situ coating of AC with short CNFs (below 200 nm) is a very attractive method for producing the next generation of carbon composite materials with a high power performance in supercapacitors working in neutral medium. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Single Photon Source with a Diamond Nanocrystal on an Optical Nanofiber

    International Nuclear Information System (INIS)

    Lars Liebermeister

    2014-01-01

    The development of high yield single photon sources is crucial for applications in quantum information science as well as for experiments on the foundations of quantum physics. The NV-center in diamond is a promising solid state candidate. By using nanodiamonds the single photon emission can easily be coupled to integrated nano-optical and plasmonic structures. Our approach is to utilize efficient coupling of fluorescence of a single NV-center to the evanescent field of an optical nanofiber. A hybrid microscope (confocal microscope combined with an AFM) allows to optically characterize and preselect diamond nanocrystals and then to apply an AFM nanomanipulation technique to move a selected nanodiamond deterministically onto the tapered optical fiber. We report on first results with single diamond nanocrystals containing several NV-centers positioned on a tapered optical fiber. We observe fluorescence emission in the guided mode of the fiber. The second order correlation recorded between the free-space and the guided fluorescence shows pronounced antibunching. This demonstrated efficient evanescent coupling with low background. (author)

  3. Graphene-augmented nanofiber scaffolds demonstrate new features in cells behaviour

    Science.gov (United States)

    Kazantseva, Jekaterina; Ivanov, Roman; Gasik, Michael; Neuman, Toomas; Hussainova, Irina

    2016-07-01

    Three-dimensional (3D) customized scaffolds capable to mimic a native extracellular matrix open new frontiers in cells manipulation and advanced therapy. The major challenge is in a proper substrate for in vitro models on engineered scaffolds, capable to modulate cells differentiation. Here for the first time we demonstrate novel design and functionality of the 3D porous scaffolds of aligned, self-assembled ceramic nanofibers of ultra-high anisotropy ratio (~107), augmented into graphene shells. This unique hybrid nano-network allows an exceptional combination of selective guidance stimuli of stem cells differentiation, immune reactions variations, and local immobilization of cancer cells, which was not available before. The scaffolds were shown to be able to direct human mesenchymal stem cells (important for stimulation of neuronal and muscle cells) preferential orientation, to suppress major inflammatory factors, and to localize cancer cells; all without additions of specific culture media. The selective downregulation of specific cytokines is anticipated as a new tool for understanding of human immune system and ways of treatment of associated diseases. The effects observed are self-regulated by cells only, without side effects, usually arising from use of external factors. New scaffolds may open new horizons for stem cells fate control such as towards axons and neurites regeneration (Alzheimer’s disease) as well as cancer therapy development.

  4. Electrochemically Active Polyaniline (PANi) Coated Carbon Nanopipes and PANi Nanofibers Containing Composite.

    Science.gov (United States)

    Ramana, G Venkata; Kumar, P Sampath; Srikanth, Vadali V S S; Padya, Balaji; Jain, P K

    2015-02-01

    A composite constituted by carbon nanopipes (CNPs) and polyaniline nanofibers (PANi NFs) is synthesized using in-situ chemical oxidative polymerization. Owing to its electrochemical activity the composite is found to be suitable as a working electrode material in hybrid type supercapacitors. Microstructural and phase analyses of the composite showed that (i) CNP surfaces are coated with PANi and (ii) PANi coated CNPs are distributed among PANi NFs. The composite shows an excellent electrochemical activity and a high specific capacitance of ~224.39 F/g. The electro-chemical activity of the composite is explicated in correlation with crystallinity, intrinsic oxidation state, and doping degree of PANi in the composite. The electro-chemical activity of the composite is also explicated in correlation with BET surface area and ordered meso-porosity pertaining to the composite. Charge/discharge curves indicate that the specific capacitance of the composite is a result of electric double-layer capacitance offered by CNPs and Faradaic pseudo capacitance offered by PANi NFs.

  5. Preparation and Characterization of Amphiphilic Triblock Terpolymer-Based Nanofibers as Antifouling Biomaterials

    KAUST Repository

    Cho, Youngjin

    2012-05-14

    Antifouling surfaces are critical for the good performance of functional materials in various applications including water filtration, medical implants, and biosensors. In this study, we synthesized amphiphilic triblock terpolymers (tri-BCPs, coded as KB) and fabricated amphiphilic nanofibers by electrospinning of solutions prepared by mixing the KB with poly(lactic acid) (PLA) polymer. The resulting fibers with amphiphilic polymer groups exhibited superior antifouling performance to the fibers without such groups. The adsorption of bovine serum albumin (BSA) on the amphiphilic fibers was about 10-fold less than that on the control surfaces from PLA and PET fibers. With the increase of the KB content in the amphiphilic fibers, the resistance to adsorption of BSA was increased. BSA was released more easily from the surface of the amphiphilic fibers than from the surface of hydrophobic PLA or PET fibers. We have also investigated the structural conformation of KB in fibers before and after annealing by contact angle measurements, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and coarse-grained molecular dynamics (CGMD) simulation to probe the effect of amphiphilic chain conformation on antifouling. The results reveal that the amphiphilic KB was evenly distributed within as-spun hybrid fibers, while migrated toward the core from the fiber surface during thermal treatment, leading to the reduction in antifouling. This suggests that the antifouling effect of the amphiphilic fibers is greatly influenced by the arrangement of amphiphilic groups in the fibers. © 2012 American Chemical Society.

  6. Hybrid Nanogenerator for Concurrently Harvesting Biomechanical and Biochemical Energy

    KAUST Repository

    Hansen, Benjamin J.

    2010-07-27

    Harvesting energy from multiple sources available in our personal and daily environments is highly desirable, not only for powering personal electronics, but also for future implantable sensor-transmitter devices for biomedical and healthcare applications. Here we present a hybrid energy scavenging device for potential in vivo applications. The hybrid device consists of a piezoelectric poly(vinylidene fluoride) nanofiber nanogenerator for harvesting mechanical energy, such as from breathing or from the beat of a heart, and a flexible enzymatic biofuel cell for harvesting the biochemical (glucose/O2) energy in biofluid, which are two types of energy available in vivo. The two energy harvesting approaches can work simultaneously or individually, thereby boosting output and lifetime. Using the hybrid device, we demonstrate a "self-powered" nanosystem by powering a ZnO nanowire UV light sensor. © 2010 American Chemical Society.

  7. Nanocomposite Electrospun Nanofiber Membranes for Environmental Remediation.

    Science.gov (United States)

    Homaeigohar, Shahin; Elbahri, Mady

    2014-02-10

    Rapid worldwide industrialization and population growth is going to lead to an extensive environmental pollution. Therefore, so many people are currently suffering from the water shortage induced by the respective pollution, as well as poor air quality and a huge fund is wasted in the world each year due to the relevant problems. Environmental remediation necessitates implementation of novel materials and technologies, which are cost and energy efficient. Nanomaterials, with their unique chemical and physical properties, are an optimum solution. Accordingly, there is a strong motivation in seeking nano-based approaches for alleviation of environmental problems in an energy efficient, thereby, inexpensive manner. Thanks to a high porosity and surface area presenting an extraordinary permeability (thereby an energy efficiency) and selectivity, respectively, nanofibrous membranes are a desirable candidate. Their functionality and applicability is even promoted when adopting a nanocomposite strategy. In this case, specific nanofillers, such as metal oxides, carbon nanotubes, precious metals, and smart biological agents, are incorporated either during electrospinning or in the post-processing. Moreover, to meet operational requirements, e.g., to enhance mechanical stability, decrease of pressure drop, etc. , nanofibrous membranes are backed by a microfibrous non-woven forming a hybrid membrane. The novel generation of nanocomposite/hybrid nanofibrous membranes can perform extraordinarily well in environmental remediation and control. This reality justifies authoring of this review paper.

  8. Nanocomposite Electrospun Nanofiber Membranes for Environmental Remediation

    Directory of Open Access Journals (Sweden)

    Shahin Homaeigohar

    2014-02-01

    Full Text Available Rapid worldwide industrialization and population growth is going to lead to an extensive environmental pollution. Therefore, so many people are currently suffering from the water shortage induced by the respective pollution, as well as poor air quality and a huge fund is wasted in the world each year due to the relevant problems. Environmental remediation necessitates implementation of novel materials and technologies, which are cost and energy efficient. Nanomaterials, with their unique chemical and physical properties, are an optimum solution. Accordingly, there is a strong motivation in seeking nano-based approaches for alleviation of environmental problems in an energy efficient, thereby, inexpensive manner. Thanks to a high porosity and surface area presenting an extraordinary permeability (thereby an energy efficiency and selectivity, respectively, nanofibrous membranes are a desirable candidate. Their functionality and applicability is even promoted when adopting a nanocomposite strategy. In this case, specific nanofillers, such as metal oxides, carbon nanotubes, precious metals, and smart biological agents, are incorporated either during electrospinning or in the post-processing. Moreover, to meet operational requirements, e.g., to enhance mechanical stability, decrease of pressure drop, etc., nanofibrous membranes are backed by a microfibrous non-woven forming a hybrid membrane. The novel generation of nanocomposite/hybrid nanofibrous membranes can perform extraordinarily well in environmental remediation and control. This reality justifies authoring of this review paper.

  9. Lecithin blended polyamide-6 high aspect ratio nanofiber scaffolds via electrospinning for human osteoblast cell culture

    Energy Technology Data Exchange (ETDEWEB)

    Nirmala, R. [Bio-nano System Engineering, College of Engineering, Chonbuk National University, Jeonju, 561 756 (Korea, Republic of); Park, Hye-Min [Department of Pharmacology and Toxicology, College of Veterinary Medicine, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); Navamathavan, R. [School of Advanced Materials Engineering, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); Kang, Hyung-Sub [Department of Pharmacology and Toxicology, College of Veterinary Medicine, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); El-Newehy, Mohamed H. [Petrochemical Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Kim, Hak Yong, E-mail: khy@jbnu.ac.kr [Petrochemical Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Center for Healthcare Technology and Development, Chonbuk National University, Jeonju, 561 756 (Korea, Republic of)

    2011-03-12

    In this study, we focused on the preparation and characterization of lecithin blended polyamide-6 nanofibers via an electrospinning process for human osteoblastic (HOB) cell culture applications. The morphological, structural characterizations and thermal properties of polyamide-6/lecithin nanofibers were determined by using scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry (TGA). SEM images revealed that the nanofibers were well-oriented with good incorporation of lecithin. FT-IR results indicated the presence of amino groups of lecithin in the blended nanofibers. TGA analysis revealed that the onset degradation temperature decreased with increasing lecithin content in the blended nanofibers. The morphological features of cells attached on polyamide-6/lecithin nanofibers were confirmed by SEM. The adhesion, viability and proliferation properties of osteoblast cells on the polyamide-6/lecithin blended nanofibers were analyzed by in vitro cell compatibility test. This study demonstrated the non-cytotoxic behavior of electrospun polyamide-6/lecithin nanofibers for the osteoblast cell culture.

  10. Lecithin blended polyamide-6 high aspect ratio nanofiber scaffolds via electrospinning for human osteoblast cell culture

    International Nuclear Information System (INIS)

    Nirmala, R.; Park, Hye-Min; Navamathavan, R.; Kang, Hyung-Sub; El-Newehy, Mohamed H.; Kim, Hak Yong

    2011-01-01

    In this study, we focused on the preparation and characterization of lecithin blended polyamide-6 nanofibers via an electrospinning process for human osteoblastic (HOB) cell culture applications. The morphological, structural characterizations and thermal properties of polyamide-6/lecithin nanofibers were determined by using scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry (TGA). SEM images revealed that the nanofibers were well-oriented with good incorporation of lecithin. FT-IR results indicated the presence of amino groups of lecithin in the blended nanofibers. TGA analysis revealed that the onset degradation temperature decreased with increasing lecithin content in the blended nanofibers. The morphological features of cells attached on polyamide-6/lecithin nanofibers were confirmed by SEM. The adhesion, viability and proliferation properties of osteoblast cells on the polyamide-6/lecithin blended nanofibers were analyzed by in vitro cell compatibility test. This study demonstrated the non-cytotoxic behavior of electrospun polyamide-6/lecithin nanofibers for the osteoblast cell culture.

  11. Reactive electrospinning and biodegradation of cross-linked methacrylated polycarbonate nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Wu Ruizhi; Zhang Jianfeng; Fan Yuwei; Xu Xiaoming [Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, 1100 Florida Avenue, Box 137, New Orleans, LA 70119 (United States); Stoute, Diana; Lallier, Thomas, E-mail: xxu@lsuhsc.edu [Department of Cell Biology and Anatomy, Louisiana State University Health Science Center, 1100 Florida Avenue, Box 137, New Orleans, LA 70119 (United States)

    2011-06-15

    The objectives of this study were to fabricate cross-linked biodegradable polycarbonate nanofibers and to investigate their biodegradability by different enzymes. Poly(2,3-dihydroxycarbonate) was synthesized from naturally occurring l-tartaric acid. The hydroxyl groups on the functional polycarbonate were converted to methacrylate groups to enable the polymer to cross-link under UV irradiation. Smooth cross-linked methacrylated polycarbonate nanofibers (300-1800 nm) were fabricated by a reactive electrospinning process with in situ UV radiation from a mixed solution of linear methacrylated polycarbonate (MPC) and poly(ethylene oxide) (PEO) (MPC:PEO = 9:1) in methanol/chloroform (50/50). These cross-linked nanofibers have shown excellent solvent resistance and their solubility decreases with increasing degree of cross-linking. The thermal properties of linear and cross-linked polycarbonate nanofibers were investigated by differential scanning calorimetry and thermogravimetric analysis. The cross-linked polycarbonate nanofibers show no melting point below 200 {sup 0}C and their decomposition temperature increases with increasing cross-linking degree. Their biodegradation products by five different enzymes were analyzed using liquid chromatography-mass spectrometry (LC-MS). The biodegradability of the polycarbonate nanofibers decreases with increasing cross-linking degree. These nanofibers were found to support human fibroblast survival and to promote cell attachment. This study demonstrates that cross-linked biodegradable polycarbonate nanofibers with different chemical properties and biodegradability can be fabricated using the novel reactive electrospinning technology to meet the needs of different biomedical applications.

  12. Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yongzheng; Li, Yajing; Zhang, Jianfeng; Yu, Zhongzhen; Yang, Dongzhi, E-mail: yangdz@mail.buct.edu.cn

    2015-06-01

    The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO{sub 3} aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20–30 nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50 wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields. - Highlights: • Silver mirror reaction was used to prepare nanofibers loaded with silver nanoparticles. • The SAED patterns demonstrated the monocrystallinity of silver nanocrystals. • The XRD results showed nanoparticles tended to be face-centered cubic single silver. • The material showed excellent antimicrobial activities against bacteria and fungi.

  13. Measurement of fluorescence emission spectrum of few strongly driven atoms using an optical nanofiber.

    Science.gov (United States)

    Das, Manoj; Shirasaki, A; Nayak, K P; Morinaga, M; Le Kien, Fam; Hakuta, K

    2010-08-02

    We show that the fluorescence emission spectrum of few atoms can be measured by using an optical nanofiber combined with the optical heterodyne and photon correlation spectroscopy. The observed fluorescence spectrum of the atoms near the nanofiber shows negligible effects of the atom-surface interaction and agrees well with the Mollow triplet spectrum of free-space atoms at high excitation intensity.

  14. Force and time-dependent self-assembly, disruption and recovery of supramolecular peptide amphiphile nanofibers.

    Science.gov (United States)

    Dikecoglu, F Begum; Topal, Ahmet E; Ozkan, Alper D; Tekin, E Deniz; Tekinay, Ayse B; Guler, Mustafa O; Dana, Aykutlu

    2018-07-13

    Biological feedback mechanisms exert precise control over the initiation and termination of molecular self-assembly in response to environmental stimuli, while minimizing the formation and propagation of defects through self-repair processes. Peptide amphiphile (PA) molecules can self-assemble at physiological conditions to form supramolecular nanostructures that structurally and functionally resemble the nanofibrous proteins of the extracellular matrix, and their ability to reconfigure themselves in response to external stimuli is crucial for the design of intelligent biomaterials systems. Here, we investigated real-time self-assembly, deformation, and recovery of PA nanofibers in aqueous solution by using a force-stabilizing double-pass scanning atomic force microscopy imaging method to disrupt the self-assembled peptide nanofibers in a force-dependent manner. We demonstrate that nanofiber damage occurs at tip-sample interaction forces exceeding 1 nN, and the damaged fibers subsequently recover when the tip pressure is reduced. Nanofiber ends occasionally fail to reconnect following breakage and continue to grow as two individual nanofibers. Energy minimization calculations of nanofibers with increasing cross-sectional ellipticity (corresponding to varying levels of tip-induced fiber deformation) support our observations, with high-ellipticity nanofibers exhibiting lower stability compared to their non-deformed counterparts. Consequently, tip-mediated mechanical forces can provide an effective means of altering nanofiber integrity and visualizing the self-recovery of PA assemblies.

  15. Synthesis and characterization of crosslinked gellan/PVA nanofibers for tissue engineering application.

    Science.gov (United States)

    Vashisth, Priya; Pruthi, Vikas

    2016-10-01

    Electrospun nanofibers based on gellan are considered as promising biomaterial for tissue engineering and wound healing applications. However, major hurdles in usage of these nanofibers are their poor stability and deprived structural consistency in aqueous medium which is a prerequisite for their application in the biomedical sector. In this investigation, three dimensional nanofibers, consisting of gellan and PVA have been fabricated and then stabilized under various crosslinking conditions in order to improve their physiochemical stability. The impacts of different crosslinking procedures on the gellan/PVA nanofibers were examined in terms of changes in morphological, mechanical, swelling and biological properties. Superior tensile strength and strain was recorded in case of crosslinked nanofibers as compared to non-crosslinked nanofibers. Contact angles and swelling properties of fabricated gellan/PVA nanofibers were found to vary with the crosslinking method. All crosslinking conditions were evaluated with regard to their response towards human dermal fibroblast (3T3L1) cells. Biocompatibility studies suggested that the fabricated crosslinked gellan/PVA nanofibers hold a great prospective in the biomedical engineering arena. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction

    International Nuclear Information System (INIS)

    Shi, Yongzheng; Li, Yajing; Zhang, Jianfeng; Yu, Zhongzhen; Yang, Dongzhi

    2015-01-01

    The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO 3 aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20–30 nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50 wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields. - Highlights: • Silver mirror reaction was used to prepare nanofibers loaded with silver nanoparticles. • The SAED patterns demonstrated the monocrystallinity of silver nanocrystals. • The XRD results showed nanoparticles tended to be face-centered cubic single silver. • The material showed excellent antimicrobial activities against bacteria and fungi

  17. Mirror-finished superhydrophobic aluminum surfaces modified by anodic alumina nanofibers and self-assembled monolayers

    Science.gov (United States)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2018-05-01

    We demonstrate mirror-finished superhydrophobic aluminum surfaces fabricated via the formation of anodic alumina nanofibers and subsequent modification with self-assembled monolayers (SAMs). High-density anodic alumina nanofibers were formed on the aluminum surface via anodizing in a pyrophosphoric acid solution. The alumina nanofibers became tangled and bundled by further anodizing at low temperature because of their own weight, and the aluminum surface was completely covered by the long falling nanofibers. The nanofiber-covered aluminum surface exhibited superhydrophilic behavior, with a contact angle measuring less than 10°. As the nanofiber-covered aluminum surface was modified with n-alkylphosphonic acid SAMs, the water contact angle drastically shifted to superhydrophobicity, measuring more than 150°. The contact angle increased with the applied voltage during pyrophosphoric acid anodizing, the anodizing time, and the number of carbon atoms contained in the SAM molecules modified on the alumina nanofibers. By optimizing the anodizing and SAM-modification conditions, superhydrophobic behavior could be achieved with only a brief pyrophosphoric acid anodizing period of 3 min and subsequent simple immersion in SAM solutions. The superhydrophobic aluminum surface exhibited a high reflectance, measuring approximately 99% across most of the visible spectrum, similar to that of an electropolished aluminum surface. Therefore, our mirror-finished superhydrophobic aluminum surface based on anodic alumina nanofibers and SAMs can be used as a reflective mirror in various optical applications such as concentrated solar power systems.

  18. Polyacrylonitrile (PAN)/crown ether composite nanofibers for the selective adsorption of cations

    NARCIS (Netherlands)

    Tas, Sinem; Kaynan, Ozge; Ozden-Yenigun, Elif; Nijmeijer, Dorothea C.

    2016-01-01

    In this study, we prepared electrospun polyacrylonitrile (PAN) nanofibers functionalized with dibenzo-18-crown-6 (DB18C6) crown ether and showed the potential of these fibers for the selective recovery of K+ from other both mono- and divalent ions in aqueous solutions. Nanofibers were characterized

  19. Design and Characterization of Electrospun Polyamide Nanofiber Media for Air Filtration Applications

    Directory of Open Access Journals (Sweden)

    Jonas Matulevicius

    2014-01-01

    Full Text Available Electrospun polyamide 6 (PA 6 and polyamide 6/6 (PA 6/6 nanofibers were produced in order to investigate their experimental characteristics with the goal of obtaining filtration relevant fiber media. The experimental design model of each PA nanofibers contained the following variables: polymer concentration, ratio of solvents, nanofiber media collection time, tip-to-collector distance, and the deposition voltage. The average diameter of the fibers, their morphology, basis weight, thickness, and resulting media solidity were investigated. Effects of each variable on the essential characteristics of PA 6/6 and PA 6 nanofiber media were studied. The comparative analysis of the obtained PA 6/6 and PA 6 nanofiber characteristics revealed that PA 6/6 had higher potential to be used in filtration applications. Based on the experimental results, the graphical representation—response surfaces—for obtaining nanofiber media with the desirable fiber diameter and basis weight characteristics were derived. Based on the modelling results the nanofiber filter media (mats were fabricated. Filtration results revealed that nanofiber filter media electrospun from PA6/6 8% (w/vol solutions with the smallest fiber diameters (62–66 nm had the highest filtration efficiency (PA6/6_30 = 84.9–90.9% and the highest quality factor (PA6/6_10 = 0.0486–0.0749 Pa−1.

  20. Superhydrophilicity of novel anodic alumina nanofibers films and their formation mechanism

    Science.gov (United States)

    Peng, Rong; Yang, Wulin; Fu, Licai; Zhu, Jiajun; Li, Deyi; Zhou, Lingping

    2017-06-01

    A novel anodic alumina nanofibers structure, which is different from the traditional porous anodic structure, has been quickly fabricated via anodizing in a new electrolyte, pyrophosphoric acid. The effects of the solution concentration and the anodizing time on the formation of the anodic alumina nanofibers were analyzed. The results show that the nanostructure of anodic alumina can change to the nanofiber oxide from the porous oxide by increasing the solution concentration. Prolonging the anodizing time is beneficial to obtain alumina nanofibers at high solution concentration. Growth behavior of the alumina nanofibers was also discussed by scanning electron microscopy observations. Owing to the unique hexagonal structure of anodic alumina as well as the preferential chemical dissolution between the porous anodic alumina and the anodic alumina nanotips, the slightly soluble anodic alumina nanotips could form novel alumina nanofibers during anodizing. The results show that the nanofibers-covered aluminum surface exhibits superhydrophilic property, with a near-zero water contact angle. Such alumina nanofibers with superhydrophilic property could be used for various potential applications.