Electrochemical properties of graphene nanosheets/polyaniline nanofibers composites as electrode for supercapacitors

NASA Astrophysics Data System (ADS)

Li, Jing; Xie, Huaqing; Li, Yang; Liu, Jie; Li, Zhuxin

Graphene nanosheets/polyaniline nanofibers (GNS/PANI) composites are synthesized via in situ polymerization of aniline monomer in HClO 4 solution. The PANI nanofibers homogeneously coating on the surface of GNS greatly improve the charge transfer reaction. The GNS/PANI composites exhibit better electrochemical performances than the pure individual components. A remarkable specific capacitance of 1130 F g -1 (based on GNS/PANI composites) is obtained at a scan rate of 5 mV s -1 in 1 M H 2SO 4 solution compared to 402 F g -1 for pure PANI and 270 F g -1 for GNS. The excellent performance is not only due to the GNS which can provide good electrical conductivity and high specific surface area, but also associate with a good redox activity of ordered PANI nanofibers. Moreover, the GNS/PANI composites present excellent long cycle life with 87% specific capacitance retained after 1000 charge/discharge processes. The resulting composites are promising electrode materials for high-performance electrical energy storage devices.

Investigation of Lithium-Air Battery Discharge Product Formed on Carbon Nanotube and Nanofiber Electrodes

NASA Astrophysics Data System (ADS)

Mitchell, Robert Revell, III

Carbon nanotubes have been actively investigated for integration in a wide variety of applications since their discovery over 20 years ago. Their myriad desirable material properties including exceptional mechanical strength, high thermal conductivities, large surface-to-volume ratios, and considerable electrical conductivities, which are attributable to a quantum mechanical ability to conduct electrons ballistically, have continued to motivate interest in this material system. While a variety of synthesis techniques exist, carbon nanotubes and nanofibers are most often conveniently synthesized using chemical vapor deposition (CVD), which involves their catalyzed growth from transition metal nanoparticles. Vertically-aligned nanotube and nanofiber carpets produced using CVD have been utilized in a variety of applications including those related to energy storage. Li-air (Li-O2) batteries have received much interest recently because of their very high theoretical energy densities (3200 Wh/kgLi2O2 ). which make them ideal candidates for energy storage devices for future fully-electric vehicles. During operation of a Li-air battery O2 is reduced on the surface a porous air cathode, reacting with Li-ions to form lithium peroxide (Li-O2). Unlike the intercalation reactions of Li-ion batteries, discharge in a Li-air cell is analogous to an electrodeposition process involving the nucleation and growth of the depositing species on a foreign substrate. Carbon nanofiber electrodes were synthesized on porous substrates using a chemical vapor deposition process and then assembled into Li-O2 cells. The large surface to volume ratio and low density of carbon nanofiber electrodes were found to yield a very high gravimetric energy density in Li-O 2 cells, approaching 75% of the theoretical energy density for Li 2O2. Further, the carbon nanofiber electrodes were found to be excellent platforms for conducting ex situ electron microscopy investigations of the deposition Li2O2 phase

Nonenzymatic glucose sensor based on renewable electrospun Ni nanoparticle-loaded carbon nanofiber paste electrode.

PubMed

Liu, Yang; Teng, Hong; Hou, Haoqing; You, Tianyan

2009-07-15

A novel nonenzymatic glucose sensor was developed based on the renewable Ni nanoparticle-loaded carbon nanofiber paste (NiCFP) electrode. The NiCF nanocomposite was prepared by combination of electrospinning technique with thermal treatment method. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed that large amounts of spherical nanoparticles were well dispersed on the surface or embedded in the carbon nanofibers. And the nanoparticles were composed of Ni and NiO, as revealed by energy dispersive X-ray spectroscopy (EDX) and X-ray powder diffraction (XRD). In application to nonenzymatic glucose determination, the renewable NiCFP electrodes, which were constructed by simply mixing the electrospun nanocomposite with mineral oil, exhibited strong and fast amperometric response without being poisoned by chloride ions. Low detection limit of 1 microM with wide linear range from 2 microM to 2.5 mM (R=0.9997) could be obtained. The current response of the proposed glucose sensor was highly sensitive and stable, attributing to the electrocatalytic performance of the firmly embedded Ni nanoparticles as well as the chemical inertness of the carbon-based electrode. The good analytical performance, low cost and straightforward preparation method made this novel electrode material promising for the development of effective glucose sensor.

Amorphous V-O-C composite nanofibers electrospun from solution precursors as binder- and conductive additive-free electrodes for supercapacitors with outstanding performance

NASA Astrophysics Data System (ADS)

Chen, Xia; Zhao, Bote; Cai, Yong; Tadé, Moses O.; Shao, Zongping

2013-11-01

Flexible V-O-C composite nanofibers were fabricated from solution precursors via electrospinning and were investigated as free-standing and additive-free film electrodes for supercapacitors. Specifically, composite nanofibers (V0, V5, V10 and V20) with different vanadyl acetylacetonate (VO(acac)2) contents of 0, 5, 10 and 20 wt% with respect to polyacrylonitrile (PAN) were prepared. The composite nanofibers were comparatively studied using XRD, Raman spectroscopy, XPS, N2 adsorption-desorption, FE-SEM, TEM and S-TEM. The vanadium element was found to be well-dispersed in the carbon nanofibers, free from the formation of an aggregated crystalline phase, even in the case of V20. A specific surface area of 587.9 m2 g-1 was reached for V10 after calcination, which is approximately twice that of the vanadium-free carbon nanofibers (V0, 300.9 m2 g-1). To perform as an electrode for supercapacitors in an aqueous electrolyte, the V10 film delivered a specific capacitance of 463 F g-1 at 1 A g-1. V10 was also able to retain a specific capacitance of 380 F g-1, even at a current density of 10 A g-1. Additionally, very stable cycling stability was achieved, maintaining an outstanding specific capacitance of 400 F g-1 at 5 A g-1 after charge-discharge cycling 5000 times. Thus, V-O-C composite nanofibers are highly attractive electrode materials for flexible, high-power, thin film energy storage devices and applications.Flexible V-O-C composite nanofibers were fabricated from solution precursors via electrospinning and were investigated as free-standing and additive-free film electrodes for supercapacitors. Specifically, composite nanofibers (V0, V5, V10 and V20) with different vanadyl acetylacetonate (VO(acac)2) contents of 0, 5, 10 and 20 wt% with respect to polyacrylonitrile (PAN) were prepared. The composite nanofibers were comparatively studied using XRD, Raman spectroscopy, XPS, N2 adsorption-desorption, FE-SEM, TEM and S-TEM. The vanadium element was found to be well

High-Performance Supercapacitor Electrode Materials from Cellulose-Derived Carbon Nanofibers.

PubMed

Cai, Jie; Niu, Haitao; Li, Zhenyu; Du, Yong; Cizek, Pavel; Xie, Zongli; Xiong, Hanguo; Lin, Tong

2015-07-15

Nitrogen-functionalized carbon nanofibers (N-CNFs) were prepared by carbonizing polypyrrole (PPy)-coated cellulose NFs, which were obtained by electrospinning, deacetylation of electrospun cellulose acetate NFs, and PPy polymerization. Supercapacitor electrodes prepared from N-CNFs and a mixture of N-CNFs and Ni(OH)2 showed specific capacitances of ∼236 and ∼1045 F g(-1), respectively. An asymmetric supercapacitor was further fabricated using N-CNFs/Ni(OH)2 and N-CNFs as positive and negative electrodes. The supercapacitor device had a working voltage of 1.6 V in aqueous KOH solution (6.0 M) with an energy density as high as ∼51 (W h) kg(-1) and a maximum power density of ∼117 kW kg(-1). The device had excellent cycle lifetime, which retained ∼84% specific capacitance after 5000 cycles of cyclic voltammetry scans. N-CNFs derived from electrospun cellulose may be useful as an electrode material for development of high-performance supercapacitors and other energy storage devices.

Flexible Fe2O3 and V2O5 nanofibers as binder-free electrodes for high-performance all-solid-state asymmetric supercapacitors.

PubMed

Jiang, He; Niu, Hao; Yang, Xue; Sun, Zhiqin; Li, Fuzhi; Wang, Qian; Qu, Fengyu

2018-04-16

Flexible highly porous Fe2O3 and V2O5 nanofibers are synthesized by a facile electrospinning method followed by calcination treatment and directly used as binder-free electrodes for high-performance supercapacitors. These Fe2O3 and V2O5 nanofibers interconnect with each other and construct three-dimensional hierarchical porous films with high specific surface area. Benefiting from the unique structural features, the intriguing binder-free Fe2O3 and V2O5 porous nanofiber electrodes possess high specific capacitance of 255 F g-1 and 256 F g-1 at 2 mV s-1 in 1 M Na2SO4 electrolyte, respectively. An all-solid-state asymmetric supercapacitor is fabricated using Fe2O3 and V2O5 nanofibers as negative and positive electrodes, respectively, and the all-solid-state asymmetric supercapacitor can be operated up to 1.8 V attributed to the wide and opposite potential window of both electrodes. The assembled all-solid-state asymmetric supercapacitor achieves a high energy density up to 32.2 Wh kg-1 at an average power density of 128.7 W kg-1 as well as excellent cycling stability and power capability. The effective and facile synthesis method and superior electrochemical performance provided in this work make electrospun Fe2O3 and V2O5 nanofibers promising electrode materials for high performance asymmetric supercapacitors. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Layer-by-layer assembled polyaniline nanofiber/multiwall carbon nanotube thin film electrodes for high-power and high-energy storage applications.

PubMed

Hyder, Md Nasim; Lee, Seung Woo; Cebeci, Fevzi Ç; Schmidt, Daniel J; Shao-Horn, Yang; Hammond, Paula T

2011-11-22

Thin film electrodes of polyaniline (PANi) nanofibers and functionalized multiwall carbon nanotubes (MWNTs) are created by layer-by-layer (LbL) assembly for microbatteries or -electrochemical capacitors. Highly stable cationic PANi nanofibers, synthesized from the rapid aqueous phase polymerization of aniline, are assembled with carboxylic acid functionalized MWNT into LbL films. The pH-dependent surface charge of PANi nanofibers and MWNTs allows the system to behave like weak polyelectrolytes with controllable LbL film thickness and morphology by varying the number of bilayers. The LbL-PANi/MWNT films consist of a nanoscale interpenetrating network structure with well developed nanopores that yield excellent electrochemical performance for energy storage applications. These LbL-PANi/MWNT films in lithium cell can store high volumetric capacitance (~238 ± 32 F/cm(3)) and high volumetric capacity (~210 mAh/cm(3)). In addition, rate-dependent galvanostatic tests show LbL-PANi/MWNT films can deliver both high power and high energy density (~220 Wh/L(electrode) at ~100 kW/L(electrode)) and could be promising positive electrode materials for thin film microbatteries or electrochemical capacitors. © 2011 American Chemical Society

Supercapacitor Electrode Materials from Highly Porous Carbon Nanofibers with Tailored Pore Distributions

NASA Astrophysics Data System (ADS)

Chathurika Abeykoon, Nimali

Environmental and human health risks associated with the traditional methods of energy production (e.g., oil and gas) and intermittency and uncertainty of renewable sources (e.g., solar and wind) have led to exploring effective and alternative energy sources to meet the growing energy demands. Electricity based on energy storage devices are the most promising solutions for realization of these objectives. Among the energy storage devices, electrochemical double layer capacitors (EDLCs) or supercapacitors have become an attractive research interest due to their outstanding performance, especially high power densities, long cycle life and rapid charge and discharge times, which enables them to utilize in many applications including consumer electronics and transportation, where high power is needed. However, low energy density of supercapacitors is a major obstacle to compete with the commercially existing high energy density energy storage device such as batteries. The fabrication of advanced electrodes materials with very high surface area from novel precursors and utilization of electrolytes with higher operating voltages are essential to enhance energy density of supercapacitors. In this work, carbon nanofibers (CNFs) from different polymer precursors with new fabrication techniques are explored to develop highly porous carbon with tailored pore distributions to match with employed ionic liquid electrolytes (which possess high working voltages), to realize high energy storage capability. Novel electrode materials derived from electrospun immiscible polymer blends and synthesized copolymers and terpolymers were described. Pore distributions of CNFs were tailored by varying the composition of polymers in immiscible blends or varying the monomer ratios of copolymer or terpolymers. Chapter 1 gives the detailed introduction of supercapacitors including history and storage principle of EDLCs, fabrication of carbon nanofiber based electrodes and electrolytes employed

Thermoelectricity in fullerene-metal heterojunctions.

PubMed

Yee, Shannon K; Malen, Jonathan A; Majumdar, Arun; Segalman, Rachel A

2011-10-12

Thermoelectricty in heterojunctions, where a single-molecule is trapped between metal electrodes, has been used to understand transport properties at organic-inorganic interfaces. (1) The transport in these systems is highly dependent on the energy level alignment between the molecular orbitals and the Fermi level (or work function) of the metal contacts. To date, the majority of single-molecule measurements have focused on simple small molecules where transport is dominated through the highest occupied molecular orbital. (2, 3) In these systems, energy level alignment is limited by the absence of electrode materials with low Fermi levels (i.e., large work functions). Alternatively, more controllable alignment between molecular orbitals and the Fermi level can be achieved with molecules whose transport is dominated by the lowest unoccupied molecular orbital (LUMO) because of readily available metals with lower work functions. Herein, we report molecular junction thermoelectric measurements of fullerene molecules (i.e., C(60), PCBM, and C(70)) trapped between metallic electrodes (i.e., Pt, Au, Ag). Fullerene junctions demonstrate the first strongly n-type molecular thermopower corresponding to transport through the LUMO, and the highest measured magnitude of molecular thermopower to date. While the electronic conductance of fullerenes is highly variable, due to fullerene's variable bonding geometries with the electrodes, the thermopower shows predictable trends based on the alignment of the LUMO with the work function of the electrodes. Both the magnitude and trend of the thermopower suggest that heterostructuring organic and inorganic materials at the nanoscale can further enhance thermoelectric performance, therein providing a new pathway for designing thermoelectric materials.

Polyethylene oxide-fullerene nanocomposites

NASA Astrophysics Data System (ADS)

Ali, Nasar; Chipara, Dorina; Lozano, Karen; Hinthorne, James; Chipara, Mircea

2017-11-01

Polyethylene oxide - fullerene nanocomposites have been prepared by using the solution path with water as solvent (only for the polymer). The dispersion of C60 within the polymer solution was achieved by high power sonication. The study aims to a better understanding on the effect of C60 nanoparticles on the macromolecular chains. Raman Wide Angle X Ray spectroscopy, Differential Scanning Calorimetry, and Thermogravimetric Analysis were used to inspect the interactions between the nanofiller and macromolecular chains. The experimental results revealed a completely different behavior of fullerene dispersed within polymeric matrices than using carbon nanotubes or nanofibers as nanofiller. The observed behavior was explained by the low aspect ratio of C60 compared to nanotubes and by the low thermal conductivity of C60 compared to the thermal conductivity of others carbon nanostructures.

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

NASA Astrophysics Data System (ADS)

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.

Robust and Flexible Aramid Nanofiber/Graphene Layer-by-Layer Electrodes.

PubMed

Kwon, Se Ra; Elinski, Meagan B; Batteas, James D; Lutkenhaus, Jodie L

2017-05-24

Aramid nanofibers (ANFs), or nanoscale Kevlar fibers, are of interest for their high mechanical performance and functional nanostructure. The dispersible nature of ANFs opens up processing opportunities for creating mechanically robust and flexible nanocomposites, particularly for energy and power applications. The challenge is to manipulate ANFs into an electrode structure that balances mechanical and electrochemical performance to yield a robust and flexible electrode. Here, ANFs and graphene oxide (GO) sheets are blended using layer-by-layer (LbL) assembly to achieve mechanically flexible supercapacitor electrodes. After reduction, the resulting electrodes exhibit an ANF-rich structure where ANFs act as a polymer matrix that interfacially interacts with reduced graphene oxide sheets. It is shown that ANF/GO deposition proceeds by hydrogen bonding and π-π interactions, leading to linear growth (1.2 nm/layer pairs) and a composition of 75 wt % ANFs and 25 wt % GO sheets. Chemical reduction leads to a high areal capacitance of 221 μF/cm 2 , corresponding to 78 F/cm 3 . Nanomechanical testing shows that the electrodes have a modulus intermediate between those of the two native materials. No cracks or defects are observed upon flexing ANF/GO films 1000 times at a radius of 5 mm, whereas a GO control shows extensive cracking. These results demonstrate that electrodes containing ANFs and reduced GO sheets are promising for flexible, mechanically robust energy and power.

Amorphous V-O-C composite nanofibers electrospun from solution precursors as binder- and conductive additive-free electrodes for supercapacitors with outstanding performance.

PubMed

Chen, Xia; Zhao, Bote; Cai, Yong; Tadé, Moses O; Shao, Zongping

2013-12-21

Flexible V-O-C composite nanofibers were fabricated from solution precursors via electrospinning and were investigated as free-standing and additive-free film electrodes for supercapacitors. Specifically, composite nanofibers (V0, V5, V10 and V20) with different vanadyl acetylacetonate (VO(acac)2) contents of 0, 5, 10 and 20 wt% with respect to polyacrylonitrile (PAN) were prepared. The composite nanofibers were comparatively studied using XRD, Raman spectroscopy, XPS, N2 adsorption-desorption, FE-SEM, TEM and S-TEM. The vanadium element was found to be well-dispersed in the carbon nanofibers, free from the formation of an aggregated crystalline phase, even in the case of V20. A specific surface area of 587.9 m(2) g(-1) was reached for V10 after calcination, which is approximately twice that of the vanadium-free carbon nanofibers (V0, 300.9 m(2) g(-1)). To perform as an electrode for supercapacitors in an aqueous electrolyte, the V10 film delivered a specific capacitance of 463 F g(-1) at 1 A g(-1). V10 was also able to retain a specific capacitance of 380 F g(-1), even at a current density of 10 A g(-1). Additionally, very stable cycling stability was achieved, maintaining an outstanding specific capacitance of 400 F g(-1) at 5 A g(-1) after charge-discharge cycling 5000 times. Thus, V-O-C composite nanofibers are highly attractive electrode materials for flexible, high-power, thin film energy storage devices and applications.

Graphene-loaded nanofiber-modified electrodes for the ultrasensitive determination of dopamine.

PubMed

Rodthongkum, Nadnudda; Ruecha, Nipapan; Rangkupan, Ratthapol; Vachet, Richard W; Chailapakul, Orawon

2013-12-04

A novel and highly sensitive electrochemical system based on electrospun graphene/polyaniline/polystyrene (G/PANI/PS) nanofiber-modified screen-printed carbon electrodes has been developed for dopamine (DA) determination. A dramatic increase (9 times) in the current signal for the redox reaction of a standard, ferri/ferrocyanide [Fe(CN)6](3-/4-) couple was found when compared to an unmodified electrode. This modified electrode also exhibited favorable electron transfer kinetics and excellent electrocatalytic activity toward the oxidation of DA. When used together with square wave voltammetry (SWV), DA can be selectively determined in the presence of the common interferents (i.e. ascorbic acid and uric acid). Under optimal conditions, a very low limit of detection (0.05 nM) and limit of quantification (0.30 nM) were achieved for DA. In addition, a wide dynamic range of 0.1 nM to 100 μM was found for this electrode system. Finally, the system can be successfully applied to determine DA in complex biological environment (e.g. human serum, urine) with excellent reproducibility. Copyright © 2013 Elsevier B.V. All rights reserved.

Electrochemical behavior of an antiviral drug acyclovir at fullerene-C(60)-modified glassy carbon electrode.

PubMed

Shetti, Nagaraj P; Malode, Shweta J; Nandibewoor, Sharanappa T

2012-12-01

Electrochemical oxidation of acyclovir at fullerene-C(60)-modified glassy carbon electrode has been investigated using cyclic and differential pulse voltammetry. In pH 7.4 phosphate buffer, acyclovir showed an irreversible oxidation peak at about 0.96V. The cyclic voltammetric results showed that fullerene-C(60)-modified glassy carbon electrode can remarkably enhance electrocatalytic activity towards the oxidation of acyclovir. The electrocatalytic behavior was further exploited as a sensitive detection scheme for the acyclovir determination by differential pulse voltammetry. Effects of anodic peak potential (E(p)/V), anodic peak current (I(p)/μA) and heterogeneous rate constant (k(0)) have been discussed. Under optimized conditions, the concentration range and detection limit were 9.0×10(-8) to 6.0×10(-6)M and 1.48×10(-8)M, respectively. The proposed method was applied to acyclovir determination in pharmaceutical samples and human biological fluids such as urine and blood plasma as a real sample. This method can also be employed in quality control and routine determination of drugs in pharmaceutical formulations. Copyright © 2012 Elsevier B.V. All rights reserved.

Carbon nanofibers obtained from electrospinning process

NASA Astrophysics Data System (ADS)

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.

Few layer graphene wrapped mixed phase TiO2 nanofiber as a potential electrode material for high performance supercapacitor applications

NASA Astrophysics Data System (ADS)

Thirugnanam, Lavanya; Sundara, Ramaprabhu

2018-06-01

A combination of favorable composition and optimized anatase/rutile mixed-phase TiO2 (MPTNF)/Hydrogen exfoliated graphene (HEG) composite nanofibers (MPTNF/HEG) and anatase/rutile mixed-phase TiO2/reduced graphene oxide (rGO) composite nanofibers (MPTNF/rGO) have been reported to enhance the electrochemical properties for supercapacitor applications. These composite nanofibers have been synthesized by an efficient route of electrospinning together with the help of easy chemical methods. Both the composites exhibit good charge storage capability with enhanced pseudocapacitance and electric double-layer capacitance (EDLC) as confirmed by cyclic voltammetry studies. MPTNF/HEG composite showed maximum specific capacitance of 210.5 F/g at the current density of 1 A/g, which was mainly due to its availability of the more active sites for ions adsorption on a few layers of graphene wrapped TiO2 nanofiber surface. The synergistic effect of anatase/rutile mixed phase with one dimensional nanostructure and the electronic interaction between TiO2 and few layer graphene provided the subsequent improvement of ion adsorption capacity. Also exhibit excellent electrochemical performance to improve the capacitive properties of TiO2 electrode materials which is required for the development of flexible electrodes in energy storage devices and open up new opportunities for high performance supercapacitors.

Treated Carbon Nanofibers for Storing Energy in Aqueous KOH

NASA Technical Reports Server (NTRS)

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

Electrospinning Nanofiber Based Organic Solar Cell

NASA Astrophysics Data System (ADS)

Yang, Zhenhua; Liu, Ying; Moffa, Maria; Nam, Chang-Yong; Pisignano, Dario; Rafailovich, Miriam

Bulk heterojunction (BHJ) polymer solar cells are an area of intense interest due to their potential to result in printable, inexpensive solar cells which can be processed onto flexible substrates. The active layer is typically spin coated from the solution of polythiophene derivatives (donor) and fullerenes (acceptor) and interconnected domains are formed because of phase separation. However, the power conversion efficiency (PCE) of BHJ solar cell is restricted by the presence of unfavorable morphological features, including dead ends or isolated domains. Here we MEH-PPV:PVP:PCBM electrospun nanofiber into BHJ solar cell for the active layer morphology optimization. Larger interfacial area between donor and acceptor is abtained with electrospinning method and the high aspect ratio of the MEH-PPV:PVP:PCBM nanofibers allow them to easily form a continuous pathway. The surface morphology is investigated with atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrospun nanofibers are discussed as a favorable structure for application in bulk-heterojunction organic solar cells. Electrospinning Nanofiber Based Bulk Heterojunction Organic Solar Cell.

Electrospun Nanofiber-Coated Membrane Separators for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Lee, Hun

Lithium-ion batteries are widely used as a power source for portable electronic devices and hybrid electric vehicles due to their excellent energy and power densities, long cycle life, and enhanced safety. A separator is considered to be the critical component in lithium-ion rechargeable batteries. The separator is placed between the positive and negative electrodes in order to prevent the physical contact of electrodes while allowing the transportation of ions. In most commercial lithium-ion batteries, polyolefin microporous membranes are commonly used as the separator due to their good chemical stability and high mechanical strength. However, some of their intrinsic natures, such as low electrolyte uptake, poor adhesion property to the electrodes, and low ionic conductivity, can still be improved to achieve higher performance of lithium-ion batteries. In order to improve these intrinsic properties, polyolefin microporous membranes can be coated with nanofibers by using electrospinning technique. Electrospinning is a simple and efficient method to prepare nanofibers which can absorb a significant amount of liquid electrolyte to achieve low internal resistance and battery performance. This research presents the preparation and investigation of composite membrane separators prepared by coating nanofibers onto polyolefin microporous membranes via electrospinning technique. Polyvinylidene fluoride polymers and copolymers were used for the preparation of electrospun nanofiber coatings because they have excellent electrochemical stability, good adhesion property, and high temperature resistance. The nanofiber coatings prepared by electrospinning form an interconnected and randomly orientated structure on the surface of the polyolefin microporous membranes. The size of the nanofibers is on a scale that does not interfere with the micropores in the membrane substrates. The resultant nanofiber-coated membranes have the potential to combine advantages of both the polyolefin

Biomass-Derived Nitrogen-Doped Carbon Nanofiber Network: A Facile Template for Decoration of Ultrathin Nickel-Cobalt Layered Double Hydroxide Nanosheets as High-Performance Asymmetric Supercapacitor Electrode.

PubMed

Lai, Feili; Miao, Yue-E; Zuo, Lizeng; Lu, Hengyi; Huang, Yunpeng; Liu, Tianxi

2016-06-01

The development of biomass-based energy storage devices is an emerging trend to reduce the ever-increasing consumption of non-renewable resources. Here, nitrogen-doped carbonized bacterial cellulose (CBC-N) nanofibers are obtained by one-step carbonization of polyaniline coated bacterial cellulose (BC) nanofibers, which not only display excellent capacitive performance as the supercapacitor electrode, but also act as 3D bio-template for further deposition of ultrathin nickel-cobalt layered double hydroxide (Ni-Co LDH) nanosheets. The as-obtained CBC-N@LDH composite electrodes exhibit significantly enhanced specific capacitance (1949.5 F g(-1) at a discharge current density of 1 A g(-1) , based on active materials), high capacitance retention of 54.7% even at a high discharge current density of 10 A g(-1) and excellent cycling stability of 74.4% retention after 5000 cycles. Furthermore, asymmetric supercapacitors (ASCs) are constructed using CBC-N@LDH composites as positive electrode materials and CBC-N nanofibers as negative electrode materials. By virtue of the intrinsic pseudocapacitive characteristics of CBC-N@LDH composites and 3D nitrogen-doped carbon nanofiber networks, the developed ASC exhibits high energy density of 36.3 Wh kg(-1) at the power density of 800.2 W kg(-1) . Therefore, this work presents a novel protocol for the large-scale production of biomass-derived high-performance electrode materials in practical supercapacitor applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-Assembled Nanorod Structures on Nanofibers for Textile Electrochemical Capacitor Electrodes with Intrinsic Tactile Sensing Capabilities.

PubMed

Shi, HaoTian H; Khalili, Nazanin; Morrison, Taylor; Naguib, Hani E

2018-05-21

A novel polyaniline nanorod (PAniNR) three-dimensional structure was successfully grown on flexible polyacrylonitrile (PAN) nanofiber substrate as the electrode material for electrochemical capacitors (ECs), constructed via self-stabilized dispersion polymerization process. The electrode offered desired mechanical properties such as flexibility and bendability, whereas it maintained optimal electrochemical characteristics. The electrode and the assembled EC cell also achieved intrinsic piezoresistive sensing properties, leading to real-time monitoring of excess mechanical pressure and bending during cell operations. The PAniNR@PAN electrodes show an average diameter of 173.6 nm, with the PAniNR growth of 50.7 nm in length. Compared to the electrodes made from pristine PAni, the gravimetric capacitance increased by 39.8% to 629.6 F/g with aqueous acidic electrolyte. The electrode and the assembled EC cell with gel electrolyte were responsive to tensile, compressive, and bending stresses with a sensitivity of 0.95 MPa -1 .

Electrosynthesis of nanofibers and nano-composite films

DOEpatents

Lin, Yuehe; Liang, Liang; Liu, Jun

2006-10-17

A method for producing an array of oriented nanofibers that involves forming a solution that includes at least one electroactive species. An electrode substrate is brought into contact with the solution. A current density is applied to the electrode substrate that includes at least a first step of applying a first substantially constant current density for a first time period and a second step of applying a second substantially constant current density for a second time period. The first and second time periods are of sufficient duration to electrically deposit on the electrode substrate an array of oriented nanofibers produced from the electroactive species. Also disclosed are films that include arrays or networks of oriented nanofibers and a method for amperometrically detecting or measuring at least one analyte in a sample.

Bacterial-cellulose-derived interconnected meso-microporous carbon nanofiber networks as binder-free electrodes for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Hao, Xiaodong; Wang, Jie; Ding, Bing; Wang, Ya; Chang, Zhi; Dou, Hui; Zhang, Xiaogang

2017-06-01

Bacterial cellulose (BC), a typical biomass prepared from the microbial fermentation process, has been proved that it can be an ideal platform for design of three-dimensional (3D) multifunctional nanomaterials in energy storage and conversion field. Here we developed a simple and general silica-assisted strategy for fabrication of interconnected 3D meso-microporous carbon nanofiber networks by confine nanospace pyrolysis of sustainable BC, which can be used as binder-free electrodes for high-performance supercapacitors. The synthesized carbon nanofibers exhibited the features of interconnected 3D networks architecture, large surface area (624 m2 g-1), mesopores-dominated hierarchical porosity, and high graphitization degree. The as-prepared electrode (CN-BC) displayed a maximum specific capacitance of 302 F g-1 at a current density of 0.5 A g-1, high-rate capability and good cyclicity in 6 M KOH electrolyte. This work, together with cost-effective preparation strategy to make high-value utilization of cheap biomass, should have significant implications in the green and mass-producible energy storage.

Indium tin oxide nanopillar electrodes in polymer/fullerene solar cells.

PubMed

Rider, David A; Tucker, Ryan T; Worfolk, Brian J; Krause, Kathleen M; Lalany, Abeed; Brett, Michael J; Buriak, Jillian M; Harris, Kenneth D

2011-02-25

Using high surface area nanostructured electrodes in organic photovoltaic (OPV) devices is a route to enhanced power conversion efficiency. In this paper, indium tin oxide (ITO) and hybrid ITO/SiO(2) nanopillars are employed as three-dimensional high surface area transparent electrodes in OPVs. The nanopillar arrays are fabricated via glancing angle deposition (GLAD) and electrochemically modified with nanofibrous PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(p-styrenesulfonate)). The structures are found to have increased surface area as characterized by porosimetry. When applied as anodes in polymer/fullerene OPVs (architecture: commercial ITO/GLAD ITO/PEDOT:PSS/P3HT:PCBM/Al, where P3HT is 2,5-diyl-poly(3-hexylthiophene) and PCBM is [6,6]-phenyl-C(61)-butyric acid methyl ester), the air-processed solar cells incorporating high surface area, PEDOT:PSS-modified ITO nanoelectrode arrays operate with improved performance relative to devices processed identically on unstructured, commercial ITO substrates. The resulting power conversion efficiency is 2.2% which is a third greater than for devices prepared on commercial ITO. To further refine the structure, insulating SiO(2) caps are added above the GLAD ITO nanopillars to produce a hybrid ITO/SiO(2) nanoelectrode. OPV devices based on this system show reduced electrical shorting and series resistance, and as a consequence, a further improved power conversion efficiency of 2.5% is recorded.

Negative differential resistance observation in complex convoluted fullerene junctions

NASA Astrophysics Data System (ADS)

Kaur, Milanpreet; Sawhney, Ravinder Singh; Engles, Derick

2018-04-01

In this work, we simulated the smallest fullerene molecule, C20 in a two-probe device model with gold electrodes. The gold electrodes comprised of (011) miller planes were carved to construct the novel geometry based four unique shapes, which were strung to fullerene molecules through mechanically controlled break junction techniques. The organized devices were later scrutinized using non-equilibrium Green's function based on the density functional theory to calculate their molecular orbitals, energy levels, charge transfers, and electrical parameters. After intense scrutiny, we concluded that five-edged and six-edged devices have the lowest and highest current-conductance values, which result from their electrode-dominating and electrode-subsidiary effects, respectively. However, an interesting observation was that the three-edged and four-edged electrodes functioned as semi-metallic in nature, allowing the C20 molecule to demonstrate its performance with the complementary effect of these electrodes in the electron conduction process of a two-probe device.

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

PubMed

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

Polymer Nanofiber Based Reversible Nano-Switch/Sensor Diode (Nanosssd) Device

NASA Technical Reports Server (NTRS)

Theofylaktos, Onoufrios (Inventor); Meador, Michael A. (Inventor); Miranda, Felix A. (Inventor); Pinto, Nicholas (Inventor); Mueller, Carl H. (Inventor); Santos-Perez, Javier (Inventor)

2017-01-01

A nanostructure device is provided and performs dual functions as a nano-switching/sensing device. The nanostructure device includes a doped semiconducting substrate, an insulating layer disposed on the doped semiconducting substrate, an electrode formed on the insulating layer, and at least one polymer nanofiber deposited on the electrode. The at least one polymer nanofiber provides an electrical connection between the electrode and the substrate and is the electroactive element in the device.

Vapor-phase polymerization of poly(3, 4-ethylenedioxythiophene) nanofibers on carbon cloth as electrodes for flexible supercapacitors.

PubMed

Zhao, Xin; Dong, Mengyang; Zhang, Junxian; Li, Yingzhi; Zhang, Qinghua

2016-09-23

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.

Vapor-phase polymerization of poly(3, 4-ethylenedioxythiophene) nanofibers on carbon cloth as electrodes for flexible supercapacitors

NASA Astrophysics Data System (ADS)

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.

Electrochemical oxidation of sulfites by DWCNTs, MWCNTs, higher fullerenes and manganese

NASA Astrophysics Data System (ADS)

Uzun, Dzhamal; Pchelarov, George; Dimitrov, Ognian; Vassilev, Sasho; Obretenov, Willi; Petrov, Konstantin

2018-03-01

Different electrocatalysts were tested for oxidation of sulfites to sulfates, namely, manganese thin films deposited on fullerenes and carbon nanotubes. The results presented clearly show that electrodes containing HFs (higher fullerenes), DWCNTs (double-wall carbon nanotubes) and manganese acetate are effective catalysts in S/O2 fuel cells. HFs and DWCNTs have high catalytic activity and can be employed as standalone catalysts. Manganese was deposited on DWCNTs, HFs and fullerenes C60/C70 by a thermal process. The electrocatalysts were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical testing was carried out by plotting the E/V polarization curve. The polarization curves of the electrodes composed of pristine DWCNTs showed the lowest overpotentials.

Spin resolved electronic transport through N@C20 fullerene molecule between Au electrodes: A first principles study

NASA Astrophysics Data System (ADS)

Caliskan, Serkan

2018-05-01

Using first principles study, through Density Functional Theory combined with Non Equilibrium Green's Function Formalism, electronic properties of endohedral N@C20 fullerene molecule joining Au electrodes (Au-N@C20) was addressed in the presence of spin property. The electronic transport behavior across the Au-N@C20 molecular junction was investigated by spin resolved transmission, density of states, molecular orbitals, differential conductance and current-voltage (I-V) characteristics. Spin asymmetric variation was clearly observed in the results due to single N atom encapsulated in the C20 fullerene cage, where the N atom played an essential role in the electronic behavior of Au-N@C20. This N@C20 based molecular bridge, exhibiting a spin dependent I-V variation, revealed a metallic behavior within the bias range from -1 V to 1 V. The induced magnetic moment, spin polarization and other relevant quantities associated with the spin resolved transport were elucidated.

Electrospun Carbon Nanofibers with in Situ Encapsulated Co₃O₄ Nanoparticles as Electrodes for High-Performance Supercapacitors.

PubMed

Abouali, Sara; Garakani, Mohammad Akbari; Zhang, Biao; Xu, Zheng-Long; Heidari, Elham Kamali; Huang, Jian-qiu; Huang, Jiaqiang; Kim, Jang-Kyo

2015-06-24

A facile electrospinning method with subsequent heat treatments is employed to prepare carbon nanofibers (CNFs) containing uniformly dispersed Co3O4 nanoparticles as electrodes for supercapacitors. The Co3O4/CNF electrodes with ∼68 wt % active particles deliver a remarkable capacitance of 586 F g(-1) at a current density of 1 A g(-1). When the current density is increased to 50 A g(-1), ∼66% of the original capacitance is retained. The electrodes also present excellent cyclic stability of 74% capacity retention after 2000 cycles at 2 A g(-1). These superior electrochemical properties are attributed to the uniform dispersion of active particles in the CNF matrix, which functions as a conductive support. The onionlike graphitic layers formed around the Co3O4 nanoparticles not only improve the electrical conductivity of the electrode but also prevent the separation of the nanoparticles from the carbon matrix.

Electrical Characterization of Polyaniline/polyethylene Oxide Nanofibers for Field Effect Transistors

NASA Technical Reports Server (NTRS)

Mueller, Carl H.; Theofylaktos, Noulie; Pinto, Nicholas J.; Robinson, Daryl C.; Miranda, Felix A.

2002-01-01

Nanofibers comprised of polyaniline/polyethylene oxide (PANI/PEO) are being developed for novel logic devices. We report the electrical conductivity of PANI/PEO nanofibers with diameters in the 100 to 200 nm range. We measured conductivity values of approx. 0.3 to 1.0 S/cm, which is higher than the values reported for thicker nanofibers, but less than the bulk value of PANI. The electrical measurements were performed by depositing the fibers on pre-electroded, oxidized silicon (Si) substrates. The excellent adherence of the nanofibers to the SiO2 as well as the gold (Au) electrodes may be useful in the design of future devices.

Guanine oxidation signal enhancement in DNA via a polyacrylonitrile nanofiber-coated and cyclic voltammetry-treated pencil graphite electrode

NASA Astrophysics Data System (ADS)

Aladag Tanik, Nilay; Demirkan, Elif; Aykut, Yakup

2018-07-01

This study investigated the electrochemical detection of specific nucleic acid hybridization sequences using a nanofiber-coated pencil graphite biosensor. The biosensor was developed to detect Val66Met single point mutations in the brain-derived neurotrophic factor gene, which is frequently observed in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and bipolar disorder. The oxidation signal of the most electroactive and stable DNA base, i.e., guanine, was used at approximately +1.0 V. Pencil graphite electrode (PGE) surfaces were coated with polyacrylonitrile nanofibers by electrospinning. Cyclic voltammetry was applied to the nanofiber-coated PGE to pretreat its surfaces. The application of cyclic voltammetry to the nanofiber-coated PGE surfaces before attaching the probe yielded a four fold increase in the oxidation signal for guanine compared with that using the untreated and uncoated PGE surface. The signal reductions were 70% for hybridization, 10% for non-complementary binding, and 14% for a single mismatch compared with the probe. The differences in full match, non-complementary, and mismatch binding indicated that the biosensor selectively detected the target, and that it was possible to determine hybridization in about 65 min. The detection limit was 0.19 μg/ml at a target concentration of 10 ppm.

Roll-to-Roll Production of Transparent Silver-Nanofiber-Network Electrodes for Flexible Electrochromic Smart Windows.

PubMed

Lin, Sen; Bai, Xiaopeng; Wang, Haiyang; Wang, Haolun; Song, Jianan; Huang, Kai; Wang, Chang; Wang, Ning; Li, Bo; Lei, Ming; Wu, Hui

2017-11-01

Electrochromic smart windows (ECSWs) are considered as the most promising alternative to traditional dimming devices. However, the electrode technology in ECSWs remains stagnant, wherein inflexible indium tin oxide and fluorine-doped tin oxide are the main materials being used. Although various complicated production methods, such as high-temperature calcination and sputtering, have been reported, the mass production of flexible and transparent electrodes remains challenging. Here, a nonheated roll-to-roll process is developed for the continuous production of flexible, extralarge, and transparent silver nanofiber (AgNF) network electrodes. The optical and mechanical properties, as well as the electrical conductivity of these products (i.e., 12 Ω sq -1 at 95% transmittance) are comparable with those AgNF networks produced via high-temperature sintering. Moreover, the as-prepared AgNF network is successfully assembled into an A4-sized ECSW with short switching time, good coloration efficiency, and flexibility. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fullerenes and disk-fullerenes

NASA Astrophysics Data System (ADS)

Deza, M.; Dutour Sikirić, M.; Shtogrin, M. I.

2013-08-01

A geometric fullerene, or simply a fullerene, is the surface of a simple closed convex 3-dimensional polyhedron with only 5- and 6-gonal faces. Fullerenes are geometric models for chemical fullerenes, which form an important class of organic molecules. These molecules have been studied intensively in chemistry, physics, crystallography, and so on, and their study has led to the appearance of a vast literature on fullerenes in mathematical chemistry and combinatorial and applied geometry. In particular, several generalizations of the notion of a fullerene have been given, aiming at various applications. Here a new generalization of this notion is proposed: an n-disk-fullerene. It is obtained from the surface of a closed convex 3-dimensional polyhedron which has one n-gonal face and all other faces 5- and 6-gonal, by removing the n-gonal face. Only 5- and 6-disk-fullerenes correspond to geometric fullerenes. The notion of a geometric fullerene is therefore generalized from spheres to compact simply connected two-dimensional manifolds with boundary. A two-dimensional surface is said to be unshrinkable if it does not contain belts, that is, simple cycles consisting of 6-gons each of which has two neighbours adjacent at a pair of opposite edges. Shrinkability of fullerenes and n-disk-fullerenes is investigated. Bibliography: 87 titles.

Polyaniline nanofiber sponge filled graphene foam as high gravimetric and volumetric capacitance electrode

NASA Astrophysics Data System (ADS)

Pedrós, J.; Boscá, A.; Martínez, J.; Ruiz-Gómez, S.; Pérez, L.; Barranco, V.; Calle, F.

2016-06-01

A 3D hierarchical porous composite structure is developed via the controlled electrodeposition of a polyaniline nanofiber sponge (PANI-NFS) that fills the pores of a chemical vapor deposited graphene foam (GF). The PANI-NFS/GF composite combines the efficient electronic transport in the GF scaffold (with 100-500 μm pore size) with the rapid diffusion of the electrolyte ions into the high-specific-surface-area and densely-packed PANI-NFS (with 100-500 nm pore size). The factor of 1000 in the pore hierarchy and the synergy between the materials, that form a supercapacitor composite electrode with an integrated extended current collector, lead to both very high gravimetric and volumetric capacitances. In particular, values of 1474 F g-1 and 86 F cm-3 for a GF filling factor of 11% (leading to an estimated value of 782 F cm-3 for 100%), respectively, are obtained at a current density of 0.47 A g-1. Moreover, the composite electrode presents a capacitance retention of 83% after 15000 cycles. This excellent behavior makes the PANI-NFS/GF composite electrodes very attractive for high-performance supercapacitors.

Electron transport in doped fullerene molecular junctions

NASA Astrophysics Data System (ADS)

Kaur, Milanpreet; Sawhney, Ravinder Singh; Engles, Derick

The effect of doping on the electron transport of molecular junctions is analyzed in this paper. The doped fullerene molecules are stringed to two semi-infinite gold electrodes and analyzed at equilibrium and nonequilibrium conditions of these device configurations. The contemplation is done using nonequilibrium Green’s function (NEGF)-density functional theory (DFT) to evaluate its density of states (DOS), transmission coefficient, molecular orbitals, electron density, charge transfer, current, and conductance. We conclude from the elucidated results that Au-C16Li4-Au and Au-C16Ne4-Au devices behave as an ordinary p-n junction diode and a Zener diode, respectively. Moreover, these doped fullerene molecules do not lose their metallic nature when sandwiched between the pair of gold electrodes.

High-Temperature Stable Anatase Titanium Oxide Nanofibers for Lithium-Ion Battery Anodes.

PubMed

Lee, Sangkyu; Eom, Wonsik; Park, Hun; Han, Tae Hee

2017-08-02

Control of the crystal structure of electrochemically active materials is an important approach to fabricating high-performance electrodes for lithium-ion batteries (LIBs). Here, we report a methodology for controlling the crystal structure of TiO 2 nanofibers by adding aluminum isopropoxide to a common sol-gel precursor solution utilized to create TiO 2 nanofibers. The introduction of aluminum cations impedes the phase transformation of electrospun TiO 2 nanofibers from the anatase to the rutile phase, which inevitably occurs in the typical annealing process utilized for the formation of TiO 2 crystals. As a result, high-temperature stable anatase TiO 2 nanofibers were created in which the crystal structure was well-maintained even at high annealing temperatures of up to 700 °C. Finally, the resulting anatase TiO 2 nanofibers were utilized to prepare LIB anodes, and their electrochemical performance was compared to pristine TiO 2 nanofibers that contain both anatase and rutile phases. Compared to the electrode prepared with pristine TiO 2 nanofibers, the electrode prepared with anatase TiO 2 nanofibers exhibited excellent electrochemical performances such as an initial Coulombic efficiency of 83.9%, a capacity retention of 89.5% after 100 cycles, and a rate capability of 48.5% at a current density of 10 C (1 C = 200 mA g -1 ).

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

PubMed

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.

Direct electrochemistry of glucose oxidase and glucose biosensing on a hydroxyl fullerenes modified glassy carbon electrode.

PubMed

Gao, Yun-Fei; Yang, Tian; Yang, Xiao-Lu; Zhang, Yu-Shuai; Xiao, Bao-Lin; Hong, Jun; Sheibani, Nader; Ghourchian, Hedayatollah; Hong, Tao; Moosavi-Movahedi, Ali Akbar

2014-10-15

Direct electrochemistry of glucose oxidase (GOD) was achieved when GOD-hydroxyl fullerenes (HFs) nano-complex was immobilized on a glassy carbon (GC) electrode and protected with a chitosan (Chit) membrane. The ultraviolet-visible absorption spectrometry (UV-vis), transmission electron microscopy (TEM), and circular dichroism spectropolarimeter (CD) methods were utilized for additional characterization of the GOD, GOD-HFs and Chit/GOD-HFs. Chit/HFs may preserve the secondary structure and catalytic properties of GOD. The cyclic voltammograms (CVs) of the modified GC electrode showed a pair of well-defined quasi-reversible redox peaks with the formal potential (E°') of 353 ± 2 mV versus Ag/AgCl at a scan rate of 0.05 V/s. The heterogeneous electron transfer constant (ks) was calculated to be 2.7 ± 0.2s(-1). The modified electrode response to glucose was linear in the concentrations ranging from 0.05 to 1.0mM, with a detection limit of 5 ± 1 μM. The apparent Michaelis-Menten constant (Km(app)) was 694 ± 8 μM. Thus, the modified electrode could be applied as a third generation biosensor for glucose with high sensitivity, selectivity and low detection limit. Copyright © 2014 Elsevier B.V. All rights reserved.

Dilute NiO/carbon nanofiber composites derived from metal organic framework fibers as electrode materials for supercapacitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Ying; Yang, Feng; Hu, Hongru

A new type of carbon nanofiber (CNF) dominated electrode materials decorated with dilute NiO particles (NiO/CNF) has been in situ fabricated by direct pyrolysis of Ni, Zn-containing metal organic framework fibers, which are skillfully constructed by assembling different proportional NiCl2·6H2O and Zn(Ac)2·2H2O with trimesic acid in the presence of N,N-dimethylformamide. With elegant combination of advantages of CNF and evenly dispersed NiO particles, as well as successful modulation of conductivity and porosity of final composites, our NiO/CNF composites display well-defined capacitive features. A high capacitance of 14926 F g–1 was obtained in 6 M KOH electrolyte when the contribution from 0.43more » wt% NiO was considered alone, contributing to over 35% of the total capacitance (234 F g–1 ). This significantly exceeds its theoretical specific capacitance of 2584 F g–1. It has been established from the Ragone plot that a largest energy density of 33.4 Wh kg–1 was obtained at the current density of 0.25 A g–1. Furthermore, such composite electrode materials show good rate capability and outstanding cycling stability up to 5000 times (only 10% loss). The present study provides a brand-new approach to design a high capacitance and stable supercapacitor electrode and the concept is extendable to other composite materials. Keywords: Metal organic framework; Nickel oxide; Carbon nanofiber; In situ synthesis; Capacitance« less

MnO2-deposited lignin-based carbon nanofiber mats for application as electrodes in symmetric pseudocapacitors.

PubMed

Youe, Won-Jae; Kim, Seok Ju; Lee, Soo-Min; Chun, Sang-Jin; Kang, Juwon; Kim, Yong Sik

2018-06-01

Low-cost, high-performance electrodes are highly attractive for practical supercapacitor applications. MnO 2 -deposited carbon nanofiber mats (MnO 2 -CNFMs) are prepared for use as binder-free supercapacitor electrodes. MnO 2 is deposited on the mats in situ by hydrothermally decomposing aqueous KMnO 4 , leading to the formation of nanocrystals of MnO 2 . The MnO 2 -CNFM electrode produced with 38.0μmol KMnO 4 (this electrode) shows a high specific capacitance of ~171.6F·g -1 at a scan rate of 5mV·s -1 . Moreover, a symmetric supercapacitor with the electrode exhibits a specific capacitance of 67.0F·g -1 , an energy density of 6.0Wh·kg -1 and a power density of 160W·kg -1 at a special current of 0.1A·g -1 . Further, the symmetric supercapacitor displays excellent cycling stability, retains approximately 99% of the capacitance after 1000cycles. The simplicity and ease of preparation of the MnO 2 -CNFMs as well as their suitability for use in coin-type supercapacitor cells make them ideal for application in cost-effective and high-performance electrodes for supercapacitors. Copyright © 2018 Elsevier B.V. All rights reserved.

Flexible Fe3O4@Carbon Nanofibers Hierarchically Assembled with MnO2 Particles for High-Performance Supercapacitor Electrodes.

PubMed

Iqbal, Nousheen; Wang, Xianfeng; Babar, Aijaz Ahmed; Zainab, Ghazala; Yu, Jianyong; Ding, Bin

2017-11-09

Increasing use of wearable electronic devices have resulted in enhanced demand for highly flexible supercapacitor electrodes with superior electrochemical performance. In this study, flexible composite membranes with electrosprayed MnO 2 particles uniformly anchored on Fe 3 O 4 doped electrospun carbon nanofibers (Fe 3 O 4 @CNF Mn ) have been prepared as flexible electrodes for high-performance supercapacitors. The interconnected porous beaded structure ensures free movement of electrolyte within the composite membranes, therefore, the developed supercapacitor electrodes not only offer high specific capacitance of ~306 F/g, but also exhibit good capacitance retention of ~85% after 2000 cycles, which certify that the synthesized electrodes offer high and stable electrochemical performance. Additionally, the supercapacitors fabricated from our developed electrodes well maintain their performance under flexural stress and exhibit a very minute change in specific capacitance even up to 180° bending angle. The developed electrode fabrication strategy integrating electrospinning and electrospray techniques paves new insights into the development of potential functional nanofibrous materials for light weight and flexible wearable supercapacitors.

Microwave-assisted preparation of carbon nanofiber-functionalized graphite felts as electrodes for polymer-based redox-flow batteries

NASA Astrophysics Data System (ADS)

Schwenke, A. M.; Janoschka, T.; Stolze, C.; Martin, N.; Hoeppener, S.; Schubert, U. S.

2016-12-01

A simple and fast microwave-assisted protocol to functionalize commercially available graphite felts (GFs) with carbon nanofibers (CNFs) for the application as electrode materials in redox-flow batteries (RFB) is demonstrated. As catalyst for the CNF synthesis nickel acetate is applied and ethanol serves as the carbon source. By the in-situ growth of CNFs, the active surface of the electrodes is increased by a factor of 50, which is determined by the electrochemical double layer capacities of the obtained materials. Furthermore, the morphology of the CNF-coating is investigated by scanning electron microscopy. Subsequently, the functionalized electrodes are applied in a polymer-based redox-flow battery (pRFB) using a TEMPO- and a viologen polymer as active materials. Due to the increased surface area as compared to an untreated graphite felt electrode, the current rating is improved by about 45% at 80 mA cm-2 and, furthermore, a decrease in overpotentials is observed. Thus, using this microwave-assisted synthesis approach, CNF-functionalized composite electrodes are prepared with a very simple protocol suitable for real life applications and an improvement of the overall performance of the polymer-based redox-flow battery is demonstrated.

Highly Flexible Freestanding Porous Carbon Nanofibers for Electrodes Materials of High-Performance All-Carbon Supercapacitors.

PubMed

Liu, Ying; Zhou, Jinyuan; Chen, Lulu; Zhang, Peng; Fu, Wenbin; Zhao, Hao; Ma, Yufang; Pan, Xiaojun; Zhang, Zhenxing; Han, Weihua; Xie, Erqing

2015-10-28

Highly flexible porous carbon nanofibers (P-CNFs) were fabricated by electrospining technique combining with metal ion-assistant acid corrosion process. The resultant fibers display high conductivity and outstanding mechanical flexibility, whereas little change in their resistance can be observed under repeatedly bending, even to 180°. Further results indicate that the improved flexibility of P-CNFs can be due to the high graphitization degree caused by Co ions. In view of electrode materials for high-performance supercapacitors, this type of porous nanostructure and high graphitization degree could synergistically facilitate the electrolyte ion diffusion and electron transportation. In the three electrodes testing system, the resultant P-CNFs electrodes can exhibit a specific capacitance of 104.5 F g(-1) (0.2 A g(-1)), high rate capability (remain 56.5% at 10 A g(-1)), and capacitance retention of ∼94% after 2000 cycles. Furthermore, the assembled symmetric supercapacitors showed a high flexibility and can deliver an energy density of 3.22 Wh kg(-1) at power density of 600 W kg(-1). This work might open a way to improve the mechanical properties of carbon fibers and suggests that this type of freestanding P-CNFs be used as effective electrode materials for flexible all-carbon supercapacitors.

Composite electrodes for electrochemical supercapacitors.

PubMed

Li, Jun; Yang, Quanmin; Zhitomirsky, Igor

2010-01-07

Manganese dioxide nanofibers with length ranged from 0.1 to 1 μm and a diameter of about 4-6 nm were prepared by a chemical precipitation method. Composite electrodes for electrochemical supercapacitors were fabricated by impregnation of the manganese dioxide nanofibers and multiwalled carbon nanotubes (MWCNT) into porous Ni plaque current collectors. Obtained composite electrodes, containing 85% of manganese dioxide and 15 mass% of MWCNT, as a conductive additive, with total mass loading of 7-15 mg cm-2, showed a capacitive behavior in 0.5-M Na2SO4 solutions. The decrease in stirring time during precipitation of the nanofibers resulted in reduced agglomeration and higher specific capacitance (SC). The highest SC of 185 F g-1 was obtained at a scan rate of 2 mV s-1 for mass loading of 7 mg cm-2. The SC decreased with increasing scan rate and increasing electrode mass.

Composite Electrodes for Electrochemical Supercapacitors

NASA Astrophysics Data System (ADS)

Li, Jun; Yang, Quan Min; Zhitomirsky, Igor

2010-03-01

Manganese dioxide nanofibers with length ranged from 0.1 to 1 μm and a diameter of about 4-6 nm were prepared by a chemical precipitation method. Composite electrodes for electrochemical supercapacitors were fabricated by impregnation of the manganese dioxide nanofibers and multiwalled carbon nanotubes (MWCNT) into porous Ni plaque current collectors. Obtained composite electrodes, containing 85% of manganese dioxide and 15 mass% of MWCNT, as a conductive additive, with total mass loading of 7-15 mg cm-2, showed a capacitive behavior in 0.5-M Na2SO4 solutions. The decrease in stirring time during precipitation of the nanofibers resulted in reduced agglomeration and higher specific capacitance (SC). The highest SC of 185 F g-1 was obtained at a scan rate of 2 mV s-1 for mass loading of 7 mg cm-2. The SC decreased with increasing scan rate and increasing electrode mass.

Nitrogen-doped carbon nanofibers derived from polypyrrole coated bacterial cellulose as high-performance electrode materials for supercapacitors and Li-ion batteries

DOE PAGES

Lei, Wen; Han, Lili; Xuan, Cuijuan; ...

2016-05-24

Here, nitrogen-doped carbon nanofiber (NDCN) was synthesized via carbonization of polypyrrole (PPy) coated bacterial cellulose (BC) composites, where BC serves as templates as well as precursor, and PPy serves as the nitrogen source. The synthesized NDCN was employed as electrode for both supercapacitors and Li-ion batteries. The large surface area exposed to electrolyte resulting from the 3D carbon networks leads to sufficient electrode/electrolyte interface and creates shorter transport paths of electrolyte ions and Li + ion. Besides, the three types of N dopants in NDCN improve the electronic conductivity, as well as superior electrochemical performance.

Stacked graphene nanofibers for electrochemical oxidation of DNA bases.

PubMed

Ambrosi, Adriano; Pumera, Martin

2010-08-21

In this article, we show that stacked graphene nanofibers (SGNFs) demonstrate superior electrochemical performance for oxidation of DNA bases over carbon nanotubes (CNTs). This is due to an exceptionally high number of accessible graphene sheet edges on the surface of the nanofibers when compared to carbon nanotubes, as shown by transmission electron microscopy and Raman spectroscopy. The oxidation signals of adenine, guanine, cytosine, and thymine exhibit two to four times higher currents than on CNT-based electrodes. SGNFs also exhibit higher sensitivity than do edge-plane pyrolytic graphite, glassy carbon, or graphite microparticle-based electrodes. We also demonstrate that influenza A(H1N1)-related strands can be sensitively oxidized on SGNF-based electrodes, which could therefore be applied to label-free DNA analysis.

Nickel incorporated carbon nanotube/nanofiber composites as counter electrodes for dye-sensitized solar cells.

PubMed

Joshi, Prakash; Zhou, Zhengping; Poudel, Prashant; Thapa, Amit; Wu, Xiang-Fa; Qiao, Qiquan

2012-09-21

A nickel incorporated carbon nanotube/nanofiber composite (Ni-CNT-CNF) was used as a low cost alternative to Pt as counter electrode (CE) for dye-sensitized solar cells (DSCs). Measurements based on energy dispersive X-rays spectroscopy (EDX) showed that the majority of the composite CE was carbon at 88.49 wt%, while the amount of Ni nanoparticles was about 11.51 wt%. Measurements based on electrochemical impedance spectroscopy (EIS) showed that the charge transfer resistance (R(ct)) of the Ni-CNT-CNF composite electrode was 0.71 Ω cm(2), much lower than that of the Pt electrode (1.81 Ω cm(2)). Such a low value of R(ct) indicated that the Ni-CNT-CNF composite carried a higher catalytic activity than the traditional Pt CE. By mixing with CNTs and Ni nanoparticles, series resistance (R(s)) of the Ni-CNT-CNF electrode was measured as 5.96 Ω cm(2), which was close to the R(s) of 5.77 Ω cm(2) of the Pt electrode, despite the significant difference in their thicknesses: ∼22 μm for Ni-CNT-CNF composite, while ∼40 nm for Pt film. This indicated that use of a thick layer (tens of microns) of Ni-CNT-CNF counter electrode does not add a significant amount of resistance to the total series resistance (R(s-tot)) in DSCs. The DSCs based on the Ni-CNT-CNF composite CEs yielded an efficiency of 7.96% with a short circuit current density (J(sc)) of 15.83 mA cm(-2), open circuit voltage (V(oc)) of 0.80 V, and fill factor (FF) of 0.63, which was comparable to the device based on Pt, that exhibited an efficiency of 8.32% with J(sc) of 15.01 mA cm(-2), V(oc) of 0.83, and FF of 0.67.

Ultrasound-assisted preparation of electrospun carbon nanofiber/graphene composite electrode for supercapacitors

NASA Astrophysics Data System (ADS)

Dong, Qiang; Wang, Gang; Hu, Han; Yang, Juan; Qian, Bingqing; Ling, Zheng; Qiu, Jieshan

2013-12-01

Electrospun carbon nanofiber/graphene (CNF/G) composites are prepared by in situ electrospinning polymeric nanofibers with simultaneous spraying graphene oxide, followed by heat treatment. The freestanding carbon nanofiber web acts as a framework for sustaining graphene, which helps to prevent the agglomeration of graphene and to provide a high conductivity for the efficient charge transfer to the pores. The as-obtained CNF/G composite exhibits a specific capacitance of 183 F g-1, which is approximately 1.6 times higher than that of the pristine CNF. The results have demonstrated that the high performance of the CNF/G composite is due to the novel structure and the synergic effect of graphene and the carbon nanofibers.

Composite Electrodes for Electrochemical Supercapacitors

PubMed Central

2010-01-01

Manganese dioxide nanofibers with length ranged from 0.1 to 1 μm and a diameter of about 4–6 nm were prepared by a chemical precipitation method. Composite electrodes for electrochemical supercapacitors were fabricated by impregnation of the manganese dioxide nanofibers and multiwalled carbon nanotubes (MWCNT) into porous Ni plaque current collectors. Obtained composite electrodes, containing 85% of manganese dioxide and 15 mass% of MWCNT, as a conductive additive, with total mass loading of 7–15 mg cm−2, showed a capacitive behavior in 0.5-M Na2SO4 solutions. The decrease in stirring time during precipitation of the nanofibers resulted in reduced agglomeration and higher specific capacitance (SC). The highest SC of 185 F g−1 was obtained at a scan rate of 2 mV s−1 for mass loading of 7 mg cm−2. The SC decreased with increasing scan rate and increasing electrode mass. PMID:20672101

Investigation of electrochemical actuation by polyaniline nanofibers

NASA Astrophysics Data System (ADS)

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.

Synergistic effect of carbon nanofiber/nanotube composite catalyst on carbon felt electrode for high-performance all-vanadium redox flow battery.

PubMed

Park, Minjoon; Jung, Yang-jae; Kim, Jungyun; Lee, Ho il; Cho, Jeaphil

2013-10-09

Carbon nanofiber/nanotube (CNF/CNT) composite catalysts grown on carbon felt (CF), prepared from a simple way involving the thermal decomposition of acetylene gas over Ni catalysts, are studied as electrode materials in a vanadium redox flow battery. The electrode with the composite catalyst prepared at 700 °C (denoted as CNF/CNT-700) demonstrates the best electrocatalytic properties toward the V(2+)/V(3+) and VO(2+)/VO2(+) redox couples among the samples prepared at 500, 600, 700, and 800 °C. Moreover, this composite electrode in the full cell exhibits substantially improved discharge capacity and energy efficiency by ~64% and by ~25% at 40 mA·cm(-2) and 100 mA·cm(-2), respectively, compared to untreated CF electrode. This outstanding performance is due to the enhanced surface defect sites of exposed edge plane in CNF and a fast electron transfer rate of in-plane side wall of the CNT.

The application of electrospun titania nanofibers in dye-sensitized solar cells.

PubMed

Krysova, Hana; Zukal, Arnost; Trckova-Barakova, Jana; Chandiran, Aravind Kumar; Nazeeruddin, Mohammad Khaja; Grätzel, Michael; Kavan, Ladislav

2013-01-01

Titania nanofibers were fabricated using the industrial Nanospider(TM) technology. The preparative protocol was optimized by screening various precursor materials to get pure anatase nanofibers. Composite films were prepared by mixing a commercial paste of nanocrystalline anatase particles with the electrospun nanofibers, which were shortened by milling. The composite films were sensitized by Ru-bipyridine dye (coded C106) and the solar conversion efficiency was tested in a dye-sensitized solar cell filled with iodide-based electrolyte solution (coded Z960). The solar conversion efficiency of a solar cell with the optimized composite electrode (η = 7.53% at AM 1.5 irradiation) outperforms that of a solar cell with pure nanoparticle film (η = 5.44%). Still larger improvement was found for lower light intensities. At 10% sun illumination, the best composite electrode showed η = 7.04%, referenced to that of pure nanoparticle film (η = 4.69%). There are non-monotonic relations between the film's surface area, dye sorption capacity and solar performance of nanofiber-containing composite films, but the beneficial effect of the nanofiber morphology for enhancement of the solar efficiency has been demonstrated.

Synthesis of chitin nanofibers, MWCNTs and MnO2 nanoflakes 3D porous network flexible gel-film for high supercapacitive performance electrodes

NASA Astrophysics Data System (ADS)

Liu, Shengnan; Li, Dagang

2017-03-01

As the porous structure and conductivity result in improvement of electrochemical properties, the chitin nanofibers (ChNFs), multi-walled carbon nanotubes (MWCNTs) and MnO2 (manganese dioxide) nanoflakes 3D porous network core-shell structure gel-film was fabricated for flexible free-standing supercapacitor electrodes. The electrodes were characterized by various techniques and the results demonstrate that the as-synthesized ChNFs/MWCNTs/MnO2 gel-film electrodes exhibits excellent supercapacitive behaviours. The ChNFs/MWCNTs/MnO2 gel-film electrode shows a high capacitance of 295.2 mF/cm2 at 0.1 mA/cm2 in 1 M Na2SO4 aqueous electrolyte because of its 3D porous structure. Furthermore, the electrodes also showed surprising cycling stability for 5000 cycles with retention rate up to 157.14% at 1 mA/cm2. The data presents great promise in the application of high-performance flexible supercapacitors with the low cost, light-weight and excellent cycling ability.

Electrospun bismuth ferrite nanofibers for potential applications in ferroelectric photovoltaic devices.

PubMed

Fei, Linfeng; Hu, Yongming; Li, Xing; Song, Ruobing; Sun, Li; Huang, Haitao; Gu, Haoshuang; Chan, Helen L W; Wang, Yu

2015-02-18

Bismuth ferrite (BFO) nanofibers were synthesized via a sol-gel-based electrospinning process followed by thermal treatment. The influences of processing conditions on the final structure of the samples were investigated. Nanofibers prepared under optimized conditions were found to have a perovskite structure with good quality of crystallization and free of impurity phase. Ferroelectric and piezoelectric responses were obtained from individual nanofiber measured on a piezoelectric force microscope. A prototype photovoltaic device using laterally aligned BFO nanofibers and interdigital electrodes was developed and its performance was examined on a standard photovoltaic system. The BFO nanofibers were found to exhibit an excellent ferroelectric photovoltaic property with the photocurrent several times larger than the literature data obtained on BFO thin films.

Improved supercapacitor performance of MnO2-electrospun carbon nanofibers electrodes by mT magnetic field

NASA Astrophysics Data System (ADS)

Zeng, Zheng; Liu, Yiyang; Zhang, Wendi; Chevva, Harish; Wei, Jianjun

2017-08-01

This work reports on a finding of mT magnetic field induced energy storage enhancement of MnO2-based supercapacitance electrodes (magneto-supercapacitor). Electrodes with MnO2 electrochemically deposited at electrospun carbon nanofibers (ECNFs) film are studied by cyclic voltammetry (CV), galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), and life cycle stability tests in the presence/absence of milli-Tesla (mT) magnetic fields derived by Helmholtz coils. In the presence of a 1.34 mT magnetic field, MnO2/ECNFs shows a magneto-enhanced capacitance of 141.7 F g-1 vs. 119.2 F g-1 (∼19% increase) with absence of magnetic field at a voltage sweeping rate of 5 mV s-1. The mechanism of the magneto-supercapacitance is discussed and found that the magnetic susceptibility of the MnO2 significantly improves the electron transfer of a pseudo-redox reaction of Mn(IV)/Mn(III) at the electrode, along with the magnetic field induced impedance effect, which may greatly enhance the interface charge density, facilitate electrolyte transportation, and improve the efficiency of cation intercalation/de-intercalation of the pseudocapacitor under mT-magnetic field exposure, resulting in enhancement of energy storage capacitance and longer charge/discharge time of the MnO2/ECNFs electrode without sacrificing its life cycle stability.

Polyvinyl Alcohol-derived carbon nanofibers/carbon nanotubes/sulfur electrode with honeycomb-like hierarchical porous structure for the stable-capacity lithium/sulfur batteries

NASA Astrophysics Data System (ADS)

Deng, Nanping; Kang, Weimin; Ju, Jingge; Fan, Lanlan; Zhuang, Xupin; Ma, Xiaomin; He, Hongsheng; Zhao, Yixia; Cheng, Bowen

2017-04-01

The honeycomb-like hierarchical porous carbon nanofibers (PCNFs)-carbon nanotubes (CNTs)-sulfur(S) composite electrode is successfully desgined and prepared through ball-milling and heating method, in which the PCNFs are carbonized from fibers in the membrane composed of Polyvinyl Alcohol and Polytetrafluoroethylene by electro-blown spinning technology. The prepared PCNFs-CNTs-S composite are regarded as cathode for lithium-sulfur battery. The tailored porous structure and CNTs in the composite facilitate construction of a high electrical conductive pathway and store more S/polysulfides, and the dissoluble loss of intermediate S species in electrolyte can also be restrained because of acidized PVA-based porous carbon nanofibers. Meanwhile, the porous strcucture and CNTs can effectively alleviate volume changes in battery cycling process. Moreover, the presence of LiNO3 in electrolyte helps the electrochemical oxidation of Li2S and LiNO3-derived surface film effectively suppresses the migration of soluble polysulfide to the Li anode surface. Therefore, the obtained PCNFs-CNTs-S cathode exhibits excellent performance in Li-S battery with a high initial discharge capacity as high as 1302.9 mAh g-1, and super stable capacity retention with 809.1 mAh g-1 after 300 cycles at the current density of 837.5 mA g-1 (0.5 C). And the rate capability of PCNFs-CNTs-S electrode is much better than those of CNTs-S and PCNFs-S electrodes.

A novel hydrogen peroxide biosensor based on hemoglobin-collagen-CNTs composite nanofibers.

PubMed

Li, J; Mei, H; Zheng, W; Pan, P; Sun, X J; Li, F; Guo, F; Zhou, H M; Ma, J Y; Xu, X X; Zheng, Y F

2014-06-01

In this paper, carbon nanotubes (CNTs) were successfully incorporated in the composite composed of hemoglobin (Hb) and collagen using co-electrospinning technology. The formed Hb-collagen-CNTs composite nanofibers possessed distinct advantage of three-dimensional porous structure, biocompatibility and excellent stability. The Hb immobilized in the electrospun nanofibers retained its natural structure and the heterogeneous electron transfer rate constant (ks) of the direct electron transfer between Hb and electrodes was 5.3s(-1). In addition, the electrospun Hb-collagen-CNTs nanofibers modified electrodes showed good electrocatalytic properties toward H2O2 with a detection limit of 0.91μM (signal-to-noise ratio of 3) and the apparent Michaelis-Menten constant (Km(app)) of 32.6μM. Copyright © 2014 Elsevier B.V. All rights reserved.

Combustion Synthesis of Fullerenes and Fullerenic Nanostructures In Microgravity

NASA Technical Reports Server (NTRS)

Howard, Jack B.; Brooker, John E. (Technical Monitor)

2002-01-01

The objectives of the proposed research were to determine the effects of gravity on fullerenes formation in flames and, based on the observed effects, to develop fundamental understanding of fullerenes formation and to identify engineering principles for fullerenes production. The research method consisted of the operation of laminar diffusion flames under normal- and reduced-gravity conditions, and the collection from the flames and subsequent analysis of condensables including any fullerenes present, using coupled high performance liquid chromatography/mass spectrometry and high resolution transmission electron microscopy. The focus included fullerene molecules C60 and C70 and fullerenic nanostructures including tubes, spherules and other shapes. The normal-gravity experiments were performed at MIT and complementary reduced-gravity experiments were to have been contributed by NASA. The independent variables of interest are gravity, fuel type, fuel/oxygen ratio, pressure, gas velocity at burner, diluent type and concentration. Given the large number of variables and the absence of data on either fullerene formation in diffusion flames or gravitational effects on fullerene formation in diffusion or premixed flames, the first part of the work was exploratory while the later part involved detailed study of the most interesting mechanisms. Samples of condensable material from laminar low pressure benzene/argon/oxygen diffusion flames were collected and analyzed by high-performance liquid chromatography to determine the yields of fullerenes, and by high-resolution transmission electron microscopy (HRTEM) to characterize the fullerenic material, i.e., curved-layer nanostructures, on and within the soot particles. The highest concentration of fullerenes was always detected just above the visible stoichiometric surface of a flame. The percentage of fullerenes in the condensable material increases with decreasing pressure. The overall highest amount of fullerenes was found

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

NASA Astrophysics Data System (ADS)

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.

Nanoengineering of 2D tin sulfide nanoflake arrays incorporated on polyaniline nanofibers with boosted capacitive behavior

NASA Astrophysics Data System (ADS)

Wang, Huanhuan; Chao, DongLiang; Liu, Jilei; Lin, Jianyi; Shen, Ze Xiang

2018-07-01

Nanoscale engineering plays an important role in designing novel electrode architecture and boosting energy storage in supercapacitors. Herein, we demonstrate the fabrication of freestanding tin sulfide based supercapacitor electrode using facile nucleation substrate control, i.e. polyaniline network. This is the first time that tin sulfide based material is fabricated as a binder-free electrode for supercapacitors. The first combination of tin sulfide and polyaniline also evokes synergistic effect to enhance the performance as the polyaniline nanofibers facilitate the growth of tin sulfide flakes in nanosize which is further proved helpful for improving the capacity and stability of the electrode. The as-obtained electrode of tin sulfide nanoflake arrays incorporated on polyaniline nanofibers (365 F g‑1 at 10 mV s‑1) exhibits superior electrochemical performance compared with micro-scaled tin sulfide (32 F g‑1 at 10 mV s‑1). The significantly improved pseudocapacitive and diffusive contributions of polyaniline nanofibers incorporated electrode are identified by quantitative kinetics analysis due to greatly decreased particle size and introduced mesopores, nanoclusters, and exposed edges. Profited from effective nanostructure engineering, a Na+ intercalation mechanism is also pointed out in boosting the electrochemical performance.

Electrochemical Selective and Simultaneous Detection of Diclofenac and Ibuprofen in Aqueous Solution Using HKUST-1 Metal-Organic Framework-Carbon Nanofiber Composite Electrode.

PubMed

Motoc, Sorina; Manea, Florica; Iacob, Adriana; Martinez-Joaristi, Alberto; Gascon, Jorge; Pop, Aniela; Schoonman, Joop

2016-10-17

In this study, the detection protocols for the individual, selective, and simultaneous determination of ibuprofen (IBP) and diclofenac (DCF) in aqueous solutions have been developed using HKUST-1 metal-organic framework-carbon nanofiber composite (HKUST-CNF) electrode. The morphological and electrical characterization of modified composite electrode prepared by film casting was studied by scanning electronic microscopy and four-point-probe methods. The electrochemical characterization of the electrode by cyclic voltammetry (CV) was considered the reference basis for the optimization of the operating conditions for chronoamperometry (CA) and multiple-pulsed amperometry (MPA). This electrode exhibited the possibility to selectively detect IBP and DCF by simple switching the detection potential using CA. However, the MPA operated under optimum working conditions of four potential levels selected based on CV shape in relation to the potential value, pulse time, and potential level number, and order allowed the selective/simultaneous detection of IBP and DCF characterized by the enhanced detection performance. For this application, the HKUST-CNF electrode exhibited a good stability and reproducibility of the results was achieved.

Electrochemical Selective and Simultaneous Detection of Diclofenac and Ibuprofen in Aqueous Solution Using HKUST-1 Metal-Organic Framework-Carbon Nanofiber Composite Electrode

PubMed Central

Motoc, Sorina; Manea, Florica; Iacob, Adriana; Martinez-Joaristi, Alberto; Gascon, Jorge; Pop, Aniela; Schoonman, Joop

2016-01-01

In this study, the detection protocols for the individual, selective, and simultaneous determination of ibuprofen (IBP) and diclofenac (DCF) in aqueous solutions have been developed using HKUST-1 metal-organic framework-carbon nanofiber composite (HKUST-CNF) electrode. The morphological and electrical characterization of modified composite electrode prepared by film casting was studied by scanning electronic microscopy and four-point-probe methods. The electrochemical characterization of the electrode by cyclic voltammetry (CV) was considered the reference basis for the optimization of the operating conditions for chronoamperometry (CA) and multiple-pulsed amperometry (MPA). This electrode exhibited the possibility to selectively detect IBP and DCF by simple switching the detection potential using CA. However, the MPA operated under optimum working conditions of four potential levels selected based on CV shape in relation to the potential value, pulse time, and potential level number, and order allowed the selective/simultaneous detection of IBP and DCF characterized by the enhanced detection performance. For this application, the HKUST-CNF electrode exhibited a good stability and reproducibility of the results was achieved. PMID:27763509

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

PubMed

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.

A Single Polyaniline Nanofiber Field Effect Transistor and Its Gas Sensing Mechanisms

PubMed Central

Chen, Dajing; Lei, Sheng; Chen, Yuquan

2011-01-01

A single polyaniline nanofiber field effect transistor (FET) gas sensor fabricated by means of electrospinning was investigated to understand its sensing mechanisms and optimize its performance. We studied the morphology, field effect characteristics and gas sensitivity of conductive nanofibers. The fibers showed Schottky and Ohmic contacts based on different electrode materials. Higher applied gate voltage contributes to an increase in gas sensitivity. The nanofiber transistor showed a 7% reversible resistance change to 1 ppm NH3 with 10 V gate voltage. The FET characteristics of the sensor when exposed to different gas concentrations indicate that adsorption of NH3 molecules reduces the carrier mobility in the polyaniline nanofiber. As such, nanofiber-based sensors could be promising for environmental and industrial applications. PMID:22163969

Fullerene-C60-modified electrode as a sensitive voltammetric sensor for detection of nandrolone--an anabolic steroid used in doping.

PubMed

Goyal, Rajendra N; Gupta, Vinod K; Bachheti, Neeta

2007-07-30

The electrochemical behaviour of nandrolone is investigated by cyclic, differential pulse and square-wave voltammetry in phosphate buffer system at fullerene-C60-modified electrode. The modified electrode shows an excellent electrocatalytic activity towards the oxidation of nandrolone resulting in a marked lowering in the peak potential and considerable improvement of the peak current as compared to the electrochemical activity at the bare glassy carbon electrode. The oxidation process is shown to be irreversible and diffusion-controlled. A linear range of 50 microM to 0.1 nM is obtained along with a detection limit and sensitivity of 0.42 nM and 0.358 nA nM(-1), respectively, in square-wave voltammetric technique. A diffusion coefficient of 4.13x10(-8) cm2 s(-1) was found for nandrolone using chronoamperometry. The effect of interferents, stability and reproducibility of the proposed method were also studied. The described method was successfully employed for the determination of nandrolone in human serum and urine samples. A cross-validation of observed results by GC-MS indicates that the results are in good agreement with each other.

Fabrication of a Highly Sensitive Single Aligned TiO2 and Gold Nanoparticle Embedded TiO2 Nano-Fiber Gas Sensor.

PubMed

Nikfarjam, Alireza; Hosseini, Seyedsina; Salehifar, Nahideh

2017-05-10

In this research, a single-aligned nanofiber of pure TiO 2 and gold nanoparticle (GNP)-TiO 2 were fabricated using a novel electro-spinning procedure equipped with secondary electrostatic fields on highly sharp triangular and rectangular electrodes provided for gas sensing applications. The sol used for spinning nanofiber consisted of titanium tetraisopropoxide (C 12 H 28 O 4 Ti), acetic acid (CH 3 COOH), ethanol (C 2 H 5 OH), polyvinylpyrrolidone (PVP), and gold nanoparticle solution. FE-SEM, TEM, and XRD were used to characterize the single nanofiber. In triangular electrodes, the electrostatic voltage for aligning single nanofiber between electrodes depends on the angle tip of the electrode, which was around 1.4-2.1, 2-2.9, and 3.2-4.1 kV for 30°, 45°, and 60°, respectively. However, by changing the shape of the electrodes to rectangular samples and by increasing distance between electrodes from 100 to 200 μm, electro-spinning applied voltage decreased. Response of pure TiO 2 single nanofiber sensor was measured for 30-200 ppb carbon monoxide gas. The triangular sample revealed better response and lower threshold than the rectangular sample. Adding appropriate amounts of GNP decreased the operating temperature and increased the responses. CO concentration threshold for the pure TiO 2 and GNP-TiO 2 triangular samples was about 5 ppb and 700 ppt, respectively.

Preparation of graphene oxide/poly (3,4-ethylenedioxytriophene): Poly (styrene sulfonate) (PEDOT:PSS) electrospun nanofibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Efelina, Vita; Widianto, Eri; Rusdiana, Dadi

2016-04-19

Graphene oxide (GO)/Poly (3,4-Ethylenedioxytriophene):Poly (styrene Sulfonate) (PEDOT:PSS) nanofibers have been successfully fabricated by a simple electrospinning technique to develop conductive nanofibers with polyvinyl alcohol (PVA) act as a carrier solution. Graphene oxide has been synthesized by Hummer’s method and has been confirmed by Raman Spectroscopy, FTIR and UV-Vis Spectroscopy. GO/PEDOT:PSS composite nanofibers. The structural and morphological properties were characterized by Scanning Electron Microscopy (SEM). The result of SEM show that GO/PEDOT:PSS nanofibers has a relatively uniform morphology nanofiber with diameter between 180 nm - 340 nm with smooth nanofiber surface. The produced nanofibers from this study can be utilized for various applicationsmore » such as flexible, conductive and transparent electrode.« less

Carbon- and Polyaniline Nanofibers Containing Composite Electrode Material for Supercapacitors.

PubMed

Ramana, Gedela Venkata; Ali, Mokhtar; Srikanth, Vadali V S S

2015-01-01

Rapid mixing chemical oxidative polymerization method is used to synthesize carbon nanofibers (CNFs) and polyaniline nanofibers (PANI NF) containing composite. Morphological, structural and phase analyses reveal that the composite is constituted by PANI coated CNFs and PANI NF. The intrinsic defects on the CNFs' surfaces allowed the nucleation and growth of PANI on them. At the same time, the use of optimal aniline concentration facilitated the simultaneous nucleation and growth of PANI NF The composite exhibits an excellent electrochemical activity with a specific capacitance of -156.92 F/g. The synergic contribution of the constituents to the overall electrochemical activity of the composite are identified.

Large Areal Mass, Mechanically Tough and Freestanding Electrode Based on Heteroatom-doped Carbon Nanofibers for Flexible Supercapacitors.

PubMed

Liu, Rong; Ma, Lina; Mei, Jia; Huang, Shu; Yang, Shaoqiang; Li, Enyuan; Yuan, Guohui

2017-02-21

A flexible and freestanding supercapacitor electrode with a N,P-co-doped carbon nanofiber network (N,P-CNFs)/graphene (GN) composite loaded on bacterial cellulose (BC) is first designed and fabricated in a simple, low-cost, and effective approach. The porous structure and excellent mechanical properties make the BC paper an ideal substrate that shows a large areal mass of 8 mg cm -2 . As a result, the flexible N,P-CNFs/GN/BC paper electrode shows appreciable areal capacitance (1990 mF cm -2 in KOH and 2588 mF cm -2 in H 2 SO 4 electrolytes) without sacrificing gravimetric capacitance (248.8 F g -1 and 323.5 F g -1 ), exhibits excellent cycling ability (without capacity loss after 20 000 cycles), and remarkable tensile strength (42.8 MPa). By direct coupling of two membrane electrodes, the symmetric supercapacitor delivers a prominent areal capacitance of 690 mF cm -2 in KOH and 898 mF cm -2 in H 2 SO 4 , and remarkable power/energy density (19.98 mW cm -2 /0.096 mW h cm -2 in KOH and 35.01 mW cm -2 /0.244 mW h cm -2 in H 2 SO 4 ). Additionally, it shows stable behavior in both bent and flat states. These results promote new opportunities for N,P-CNFs/GN/BC paper electrodes as high areal performance, freestanding electrodes for flexible supercapacitors. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of Amperometric Glucose Sensor Using Glucose Oxidase-Cellulose Nanofiber Aqueous Solution.

PubMed

Yasuzawa, Mikito; Omura, Yuya; Hiura, Kentaro; Li, Jiang; Fuchiwaki, Yusuke; Tanaka, Masato

2015-01-01

Cellulose nanofiber aqueous solution, which remained virtually transparent for more than one week, was prepared by using the clear upper layer of diluted cellulose nanofiber solution produced by wet jet milling. Glucose oxidase (GOx) was easily dissolved in this solution and GOx-immobilized electrode was easily fabricated by simple repetitious drops of GOx-cellulose solution on the surface of a platinum-iridium electrode. Glucose sensor properties of the obtained electrodes were examined in phosphate buffer solution of pH 7.4 at 40°C. The obtained electrode provided a glucose sensor response with significantly high response speed and good linear relationship between glucose concentration and response current. After an initial decrease of response sensitivity for a few days, relatively constant sensitivity was obtained for about 20 days. Nevertheless, the influence of electroactive compounds such as ascorbic acid, uric acid and acetoaminophen were not negletable.

3D Interconnected Binder-Free Electrospun MnO@C Nanofibers for Supercapacitor Devices.

PubMed

Ramadan, Mohamed; Abdellah, Ahmed M; Mohamed, Saad G; Allam, Nageh K

2018-05-22

Rational design of binder-free materials with high cyclic stability and high conductivity is a great need for high performance supercapacitors. We demonstrate a facile one-step synthesis method of binder-free MnO@C nanofibers as electrodes for supercapacitor applications. The topology of the fabricated nanofibers was investigated using FESEM and HRTEM. The X-ray photoelectron spectroscopy (XPS) and the X-ray diffraction (XRD) analyses confirm the formation of the MnO structure. The electrospun MnO@C electrodes achieve high specific capacitance of 578 F/g at 1 A/g with an outstanding cycling performance. The electrodes also show 127% capacity increasing after 3000 cycles. An asymmetric supercapacitor composed of activated carbon as the negative electrode and MnO@C as the positive electrode shows an ultrahigh energy density of 35.5 Wh/kg with a power density of 1000 W/kg. The device shows a superior columbic efficiency, cycle life, and capacity retention.

Aerogels Derived from Polymer Nanofibers and Their Applications.

PubMed

Qian, Zhenchao; Wang, Zhen; Zhao, Ning; Xu, Jian

2018-03-08

Aerogels are gels in which the solvent is supplanted by air while the pores and networks are largely maintained. Owing to their low bulk density, high porosity, and large specific surface area (SSA), aerogels are promising for many applications. Various inorganic aerogels, e.g., silica aerogels, are intensively studied. However, the mechanical brittleness of common inorganic aerogels has seriously restricted their applications. In the past decade, nanofibers have been developed as building blocks for the construction of aerogels to improve their mechanical property. Unlike traditional frameworks constructed by interconnected particles, nanofibers can form chemically cross-linked and/or physically entangled 3D skeletons, thus showing flexibility instead of brittleness. Therefore, excellent elasticity and toughness, ultralow density, high SSA, and tunable chemical composition can be expected for the polymer nanofiber-derived aerogels (PNAs). In this review, recent research progress in the fabrication, properties, and applications of PNAs is summarized. Various nanofibers, including nanocelluloses, nanochitins, and electrospun nanofibers are included, as well as carbon nanofibers from the corresponding organic precursors. Typical applications in supercapacitors, electrocatalysts for oxygen reduction reaction, flexible electrodes, oil absorbents, adsorbents, tissue engineering, stimuli-responsive materials, and catalyst carriers, are presented. Finally, the challenges and future development of PNAs are discussed. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbon nanofibers grafted on activated carbon as an electrode in high-power supercapacitors.

PubMed

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.

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

PubMed

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

2017-01-31

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 (V 2 O 5 ) is chosen as a model electrode material to explore the feasibility of the suggested concept. The heteromat V 2 O 5 electrode sheets are produced through one-pot fabrication based on concurrent electrospraying (for V 2 O 5 precursor/MWNT) and electrospinning (for PAN nanofiber) followed by calcination, leading to compact packing of V 2 O 5 materials in intimate contact with MWNTs and PAN nanofibers. As a consequence, the heteromat V 2 O 5 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 V 2 O 5 materials. In addition, elimination of heavy metallic foil current collectors, in combination with the dense packing of V 2 O 5 materials, significantly increases (electrode sheet-based) specific capacitances far beyond those accessible with conventional slurry-cast electrodes.

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

NASA Astrophysics Data System (ADS)

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.

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

PubMed Central

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. PMID:28139765

Tailored surface structure of LiFePO4/C nanofibers by phosphidation and their electrochemical superiority for lithium rechargeable batteries.

PubMed

Lee, Yoon Cheol; Han, Dong-Wook; Park, Mihui; Jo, Mi Ru; Kang, Seung Ho; Lee, Ju Kyung; Kang, Yong-Mook

2014-06-25

We offer a brand new strategy for enhancing Li ion transport at the surface of LiFePO4/C nanofibers through noble Li ion conducting pathways built along reduced carbon webs by phosphorus. Pristine LiFePO4/C nanofibers composed of 1-dimensional (1D) LiFePO4 nanofibers with thick carbon coating layers on the surfaces of the nanofibers were prepared by the electrospinning technique. These dense and thick carbon layers prevented not only electrolyte penetration into the inner LiFePO4 nanofibers but also facile Li ion transport at the electrode/electrolyte interface. In contrast, the existing strong interactions between the carbon and oxygen atoms on the surface of the pristine LiFePO4/C nanofibers were weakened or partly broken by the adhesion of phosphorus, thereby improving Li ion migration through the thick carbon layers on the surfaces of the LiFePO4 nanofibers. As a result, the phosphidated LiFePO4/C nanofibers have a higher initial discharge capacity and a greatly improved rate capability when compared with pristine LiFePO4/C nanofibers. Our findings of high Li ion transport induced by phosphidation can be widely applied to other carbon-coated electrode materials.

Plasma-enhanced chemical vapor deposition of multiwalled carbon nanofibers.

PubMed

Matthews, Kristopher; Cruden, Brett A; Chen, Bin; Meyyappan, M; Delzeit, Lance

2002-10-01

Plasma-enhanced chemical vapor deposition is used to grow vertically aligned multiwalled carbon nanofibers (MWNFs). The graphite basal planes in these nanofibers are not parallel as in nanotubes; instead they exhibit a small angle resembling a stacked cone arrangement. A parametric study with varying process parameters such as growth temperature, feedstock composition, and substrate power has been conducted, and these parameters are found to influence the growth rate, diameter, and morphology. The well-aligned MWNFs are suitable for fabricating electrode systems in sensor and device development.

Plasma-enhanced chemical vapor deposition of multiwalled carbon nanofibers

NASA Technical Reports Server (NTRS)

Matthews, Kristopher; Cruden, Brett A.; Chen, Bin; Meyyappan, M.; Delzeit, Lance

2002-01-01

Plasma-enhanced chemical vapor deposition is used to grow vertically aligned multiwalled carbon nanofibers (MWNFs). The graphite basal planes in these nanofibers are not parallel as in nanotubes; instead they exhibit a small angle resembling a stacked cone arrangement. A parametric study with varying process parameters such as growth temperature, feedstock composition, and substrate power has been conducted, and these parameters are found to influence the growth rate, diameter, and morphology. The well-aligned MWNFs are suitable for fabricating electrode systems in sensor and device development.

A novel fullerene lipoic acid derivative: Synthesis and preparation of self-assembled monolayers on gold

NASA Astrophysics Data System (ADS)

Viana, A. S.; Leupold, S.; Eberle, C.; Shokati, T.; Montforts, F.-P.; Abrantes, L. M.

2007-11-01

Synthesis and preparation of self-assembled monolayers of a novel fullerene lipoic acid derivative on gold are reported. The presence of densely packed SAMs was confirmed by ellipsometry and cyclic voltammetry. The electrochemical response of the modified electrode in organic media exhibits the first two redox peaks characteristic of the extended π-electron system of fullerene. C 60 surface coverage (1.4 × 10 -10 mol cm -2) has been electrochemically determined by the redox process of the adsorbed fullerene moiety and by reductive desorption of the SAM in strong alkaline solution. Electrochemical data indicate that all four sulphur atoms are involved in the self-assembly process, providing an increase of SAM stability in comparison to mono or di-thiolated appended molecules. Visualisation of discrete fullerene molecules by scanning tunnelling microscopy supplied further evidence for gold modification and molecular distribution on the surface. Mixed monolayers of hexanethiol and fullerene derivatives in a proportion of 1:2 have been also studied with the purpose of controlling the amount and distribution of fullerene units on the gold surface.

Fullerene derivatives as electron acceptors for organic photovoltaic cells.

PubMed

Mi, Dongbo; Kim, Ji-Hoon; Kim, Hee Un; Xu, Fei; Hwang, Do-Hoon

2014-02-01

Energy is currently one of the most important problems humankind faces. Depletion of traditional energy sources such as coal and oil results in the need to develop new ways to create, transport, and store electricity. In this regard, the sun, which can be considered as a giant nuclear fusion reactor, represents the most powerful source of energy available in our solar system. For photovoltaic cells to gain widespread acceptance as a source of clean and renewable energy, the cost per watt of solar energy must be decreased. Organic photovoltaic cells, developed in the past two decades, have potential as alternatives to traditional inorganic semiconductor photovoltaic cells, which suffer from high environmental pollution and energy consumption during production. Organic photovoltaic cells are composed of a blended film of a conjugated-polymer donor and a soluble fullerene-derivative acceptor sandwiched between a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-coated indium tin oxide positive electrode and a low-work-function metal negative electrode. Considerable research efforts aim at designing and synthesizing novel fullerene derivatives as electron acceptors with up-raised lowest unoccupied molecular orbital energy, better light-harvesting properties, higher electron mobility, and better miscibility with the polymer donor for improving the power conversion efficiency of the organic photovoltaic cells. In this paper, we systematically review novel fullerene acceptors synthesized through chemical modification for enhancing the photovoltaic performance by increasing open-circuit voltage, short-circuit current, and fill factor, which determine the performance of organic photovoltaic cells.

Recent Advances in Electrochemical Biosensors Based on Fullerene-C60 Nano-Structured Platforms

PubMed Central

Pilehvar, Sanaz; De Wael, Karolien

2015-01-01

Nanotechnology is becoming increasingly important in the field of (bio)sensors. The performance and sensitivity of biosensors is greatly improved with the integration of nanomaterials into their construction. Since its first discovery, fullerene-C60 has been the object of extensive research. Its unique and favorable characteristics of easy chemical modification, conductivity, and electrochemical properties has led to its tremendous use in (bio)sensor applications. This paper provides a concise review of advances in fullerene-C60 research and its use as a nanomaterial for the development of biosensors. We examine the research work reported in the literature on the synthesis, functionalization, approaches to nanostructuring electrodes with fullerene, and outline some of the exciting applications in the field of (bio)sensing. PMID:26610583

Recent Advances in Electrochemical Biosensors Based on Fullerene-C60 Nano-Structured Platforms.

PubMed

Pilehvar, Sanaz; De Wael, Karolien

2015-11-23

Nanotechnology is becoming increasingly important in the field of (bio)sensors. The performance and sensitivity of biosensors is greatly improved with the integration of nanomaterials into their construction. Since its first discovery, fullerene-C60 has been the object of extensive research. Its unique and favorable characteristics of easy chemical modification, conductivity, and electrochemical properties has led to its tremendous use in (bio)sensor applications. This paper provides a concise review of advances in fullerene-C60 research and its use as a nanomaterial for the development of biosensors. We examine the research work reported in the literature on the synthesis, functionalization, approaches to nanostructuring electrodes with fullerene, and outline some of the exciting applications in the field of (bio)sensing.

Tunable Graphitic Carbon Nano-Onions Development in Carbon Nanofibers for Multivalent Energy Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwarz, Haiqing L.

2016-01-01

We developed a novel porous graphitic carbon nanofiber material using a synthesis strategy combining electrospinning and catalytic graphitization. RF hydrogel was used as carbon precursors, transition metal ions were successfully introduced into the carbon matrix by binding to the carboxylate groups of a resorcinol derivative. Transition metal particles were homogeneously distributed throughout the carbon matrix, which are used as in-situ catalysts to produce graphitic fullerene-like nanostructures surrounding the metals. The success design of graphitic carbons with enlarged interlayer spacing will enable the multivalent ion intercalation for the development of multivalent rechargeable batteries.

Vertically aligned carbon nanofiber as nano-neuron interface for monitoring neural function.

PubMed

Yu, Zhe; McKnight, Timothy E; Ericson, M Nance; Melechko, Anatoli V; Simpson, Michael L; Morrison, Barclay

2012-05-01

Neural chips, which are capable of simultaneous multisite neural recording and stimulation, have been used to detect and modulate neural activity for almost thirty years. As neural interfaces, neural chips provide dynamic functional information for neural decoding and neural control. By improving sensitivity and spatial resolution, nano-scale electrodes may revolutionize neural detection and modulation at cellular and molecular levels as nano-neuron interfaces. We developed a carbon-nanofiber neural chip with lithographically defined arrays of vertically aligned carbon nanofiber electrodes and demonstrated its capability of both stimulating and monitoring electrophysiological signals from brain tissues in vitro and monitoring dynamic information of neuroplasticity. This novel nano-neuron interface may potentially serve as a precise, informative, biocompatible, and dual-mode neural interface for monitoring of both neuroelectrical and neurochemical activity at the single-cell level and even inside the cell. The authors demonstrate the utility of a neural chip with lithographically defined arrays of vertically aligned carbon nanofiber electrodes. The new device can be used to stimulate and/or monitor signals from brain tissue in vitro and for monitoring dynamic information of neuroplasticity both intracellularly and at the single cell level including neuroelectrical and neurochemical activities. Copyright © 2012 Elsevier Inc. All rights reserved.

Urea impedimetric biosensing using electrospun nanofibers modified with zinc oxide nanoparticles

NASA Astrophysics Data System (ADS)

Migliorini, Fernanda L.; Sanfelice, Rafaela C.; Mercante, Luiza A.; Andre, Rafaela S.; Mattoso, Luiz H. C.; Correa, Daniel. S.

2018-06-01

Reliable analytical techniques to evaluate dairy products, including milk, are of outmost importance to ensure food safety against contaminants. Among possible substances employed as adulterants in milk, urea raises deep concern due to its harmful effects to consumer's health. In the present study, a biosensing platform was developed to be applied in the electrochemical detection of urea. The sensing platform was fabricated using polymeric electrospun nanofibers of polyamide 6 (PA6) and polypyrrole (PPy) deposited onto fluorine doped tin oxide (FTO) electrodes, which were then modified with zinc oxide nanoparticles (ZnO). This material showed excellent properties for the immobilization of urease enzyme, conferring the FTO/PA6/PPy/ZnO/urease electrode high sensitivity for urea detection within the concentration range between 0.1 and 250 mg dL-1 with a limit of detection of 0.011 mg dL-1. The results achieved evidence the potential of electrospun nanofibers-based electrodes for applications in biosensors aiming at dairy products analysis.

Label-Free Detection of Cardiac Troponin-I Using Carbon Nanofiber Based Nanoelectrode Arrays

NASA Technical Reports Server (NTRS)

Periyakaruppan, Adaikkappan; Koehne, Jessica Erin; Gandhiraman, Ram P.; Meyyappan, M.

2013-01-01

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. A carbon nanofiber (CNF) multiplexed array has been fabricated with 9 sensing pads, each containing 40,000 carbon nanofibers as nanoelectrodes. Here, we report the use of vertically aligned CNF nanoelectrodes for the detection of cardiac Troponin-I for the early diagnosis of myocardial infarction. Antibody, antitroponin, probe immobilization and subsequent binding to human cardiac troponin-I were characterized using electrochemical impedance spectroscopy and cyclic voltammetry techniques. Each step of the modification process resulted in changes in electrical capacitance or resistance to charge transfer due to the changes at the electrode surface upon antibody immobilization and binding to the specific antigen. This sensor demonstrates high sensitivity, down to 0.2 ng/mL, and good selectivity making this platform a good candidate for early stage diagnosis of myocardial infarction.

Purification process for vertically aligned carbon nanofibers

NASA Technical Reports Server (NTRS)

Nguyen, Cattien V.; Delziet, Lance; Matthews, Kristopher; Chen, Bin; Meyyappan, M.

2003-01-01

Individual, free-standing, vertically aligned multiwall carbon nanotubes or nanofibers are ideal for sensor and electrode applications. Our plasma-enhanced chemical vapor deposition techniques for producing free-standing and vertically aligned carbon nanofibers use catalyst particles at the tip of the fiber. Here we present a simple purification process for the removal of iron catalyst particles at the tip of vertically aligned carbon nanofibers derived by plasma-enhanced chemical vapor deposition. The first step involves thermal oxidation in air, at temperatures of 200-400 degrees C, resulting in the physical swelling of the iron particles from the formation of iron oxide. Subsequently, the complete removal of the iron oxide particles is achieved with diluted acid (12% HCl). The purification process appears to be very efficient at removing all of the iron catalyst particles. Electron microscopy images and Raman spectroscopy data indicate that the purification process does not damage the graphitic structure of the nanotubes.

Fullerene materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malhotra, R.; Ruoff, R.S.; Lorents, D.C.

1995-04-01

Fullerenes are all-carbon cage molecules. The most celebrated fullerene is the soccer-ball shaped C{sub 60}, which is composed of twenty hexagons and twelve pentagons. Because its structure is reminiscent of the geodesic domes of architect R. Buckminster Fuller, C{sub 60} is called buckminsterfullerene, and all the materials in the family are designated fullerenes. Huffman and Kraetschmer`s discovery unleashed activity around the world as scientists explored production methods, properties, and potential uses of fullerenes. Within a short period, methods for their production in electric arcs, plasmas, and flames were discovered, and several companies began selling fullerenes to the research market. Whatmore » is remarkable is that in all these methods, carbon atoms assemble themselves into cage structures. The capability for self-assembly points to some inherent stability of these structures that allows their formation. The unusual structure naturally leads to unusual properties. Among them are ready solubility in solvents and a relatively high vapor pressure for a pure carbon material. The young fullerene field has already produced a surprising array of structures for the development of carbon-base materials having completely new and different properties from any that were previously possible.« less

Combining Fullerenes and Zwitterions in non-Conjugated Polymer Interlayers to Raise Solar Cell Efficiency.

PubMed

Liu, Yao; Sheri, Madhu; Cole, Marcus D; Emrick, Todd; Russell, Thomas P

2018-06-12

Polymer zwitterions were synthesized by nucleophilic ring-opening of 3,3'-(but-2-ene-1,4-diyl)bis(1,2-oxathiolane 2,2-dioxide) (a bis-sultone) with functional perylene diimide (PDI) or fullerene monomers. Integration of these polymers into solar cell devices as cathode interlayers boosted efficiencies of fullerene-based organic photovoltaics (OPVs) from 2.75% to 10.74%, and of non-fullerene-based OPVs from 4.25% to 10.10%, demonstrating the versatility of these interlayer materials in OPVs. The fullerene-containing polymer zwitterion (C60-PZ) showed a higher interfacial dipole (∆) value and electron mobility than its PDI counterpart (PDI-PZ), affording solar cells with high efficiency. The power of PDI-PZ and C60-PZ to improve electron injection and extraction processes when positioned between metal electrodes and organic semiconductors highlights their promise to overcome energy barriers at the hard-soft materials interface of organic electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Potentiometric urea biosensor based on an immobilised fullerene-urease bio-conjugate.

PubMed

Saeedfar, Kasra; Heng, Lee Yook; Ling, Tan Ling; Rezayi, Majid

2013-12-06

A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease) bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate) (PnBA) membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10-3 M to 8.28 × 10-5 M. The biosensor's sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor's response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days.

Electrochemical energy storage by polyaniline nanofibers: high gravity assisted oxidative polymerization vs. rapid mixing chemical oxidative polymerization.

PubMed

Zhao, Yibo; Wei, Huige; Arowo, Moses; Yan, Xingru; Wu, Wei; Chen, Jianfeng; Wang, Yiran; Guo, Zhanhu

2015-01-14

Polyaniline (PANI) nanofibers prepared by high gravity chemical oxidative polymerization in a rotating packed bed (RPB) have demonstrated a much higher specific capacitance of 667.6 F g(-1) than 375.9 F g(-1) of the nanofibers produced by a stirred tank reactor (STR) at a gravimetric current of 10 A g(-1). Meanwhile, the cycling stability of the electrode is 62.2 and 65.9% for the nanofibers from RPB and STR after 500 cycles, respectively.

Enhanced output-performance of piezoelectric poly(vinylidene fluoride trifluoroethylene) fibers-based nanogenerator with interdigital electrodes and well-ordered cylindrical cavities

NASA Astrophysics Data System (ADS)

Gui, Jinzheng; Zhu, Yezi; Zhang, Lingling; Shu, Xi; Liu, Wei; Guo, Shishang; Zhao, Xingzhong

2018-02-01

A piezoelectric nanogenerator based on poly(vinylidene fluoride trifluoroethylene) [P(VDF-TrFE)] nanofibers with an Au interdigital electrode (IDT)/P(VDF-TrFE) nanofiber film/well-ordered cylindrical cavity structure was prepared by combining Au IDTs with a rotary collector to obtain highly aligned P(VDF-TrFE) nanofiber arrays. The Au IDTs work not only as parallel electrodes to collect P(VDF-TrFE) nanofibers during electrospinning but also as charge-collecting electrodes in the nanogenerator. The well-ordered cylindrical cavities improve output performance by enhancing the deformation of P(VDF-TrFE) nanofiber films when subjected to external force. The nanogenerator performs well; as an example of application, we demonstrate energy harvesting from human walking, with a peak output voltage of 5 V and a peak short-circuit current of 1.2 μA. Such a device could have practical applications in wearable, self-powered devices.

Conversion of fullerenes to diamond

DOEpatents

Gruen, Dieter M.

1994-01-01

A method of forming synthetic diamond on a substrate. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond film thickness on the substrate.

Asymmetric supercapacitors based on functional electrospun carbon nanofiber/manganese oxide electrodes with high power density and energy density

NASA Astrophysics Data System (ADS)

Lin, Sheng-Chi; Lu, Yi-Ting; Chien, Yu-An; Wang, Jeng-An; You, Ting-Hsuan; Wang, Yu-Sheng; Lin, Chih-Wen; Ma, Chen-Chi M.; Hu, Chi-Chang

2017-09-01

Carbon nanofibers modified with carboxyl groups (CNF-COOH) possessing good wettability and high porosity are homogeneously deposited with amorphous manganese dioxide (amorphous MnO2) by potentiodynamic deposition for asymmetric super-capacitors (ASCs). The potential-cycling in 1 M H2SO4 successfully enhances the hydrophilicity of carbonized polymer nanofibers and facilitates the access of electrolytes within the CNF-COOH matrix. This modification favors the deposition of amorphous MnO2 and improves its electrochemical utilization. In this composite, MnO2 homogeneously dispersed onto CNF-COOH provides desirable pseudocapacitance and the CNF-COOH network works as the electron conductor. The composite of CNF-COOH@MnO2-20 shows a high specific capacitance of 415 F g-1 at 5 mV s-1. The capacitance retention of this composite is 94% in a 10,000-cycle test. An ASC cell consisting of this composite and activated carbon as positive and negative electrodes can be reversibly charged/discharged to a cell voltage of 2.0 V in 1 M Na2SO4 and 4 mM NaHCO3 with specific energy and power of 36.7 Wh kg-1 and 354.9 W kg-1, respectively. This ASC also shows excellent cell capacitance retention (8% decay) in the 2V, 10,000-cycle stability test, revealing superior performance.

Energy Level Alignment of N-Doping Fullerenes and Fullerene Derivatives Using Air-Stable Dopant.

PubMed

Bao, Qinye; Liu, Xianjie; Braun, Slawomir; Li, Yanqing; Tang, Jianxin; Duan, Chungang; Fahlman, Mats

2017-10-11

Doping has been proved to be one of the powerful technologies to achieve significant improvement in the performance of organic electronic devices. Herein, we systematically map out the interface properties of solution-processed air-stable n-type (4-(1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)phenyl) doping fullerenes and fullerene derivatives and establish a universal energy level alignment scheme for this class of n-doped system. At low doping levels at which the charge-transfer doping induces mainly bound charges, the energy level alignment of the n-doping organic semiconductor can be described by combining integer charger transfer-induced shifts with a so-called double-dipole step. At high doping levels, significant densities of free charges are generated and the charge flows between the organic film and the conducting electrodes equilibrating the Fermi level in a classic "depletion layer" scheme. Moreover, we demonstrate that the model holds for both n- and p-doping of π-backbone molecules and polymers. With the results, we provide wide guidance for identifying the application of the current organic n-type doping technology in organic electronics.

Conversion of fullerenes to diamond

DOEpatents

Gruen, Dieter M.

1993-01-01

A method of forming synthetic diamond on a substrate is disclosed. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond thickness on the substrate.

Fullerenes in Allende Meteorite

NASA Technical Reports Server (NTRS)

Becker, L.; Bada, J. L.; Winans, R. E.; Bunch, T. E.

1994-01-01

The detection of fullerenes in deposits from meteor impacts has led to renewed interest in the possibility that fullerenes are present in meteorites. Although fullerenes have not previously been detected in the Murchison and Allende meteorites, the Allende meteorite is known to contain several well-ordered graphite particles which are remarkably similar in size and appearance to the fullerene-related structures carbon onions and nanotubes. We report that fullerenes are in fact present in trace amounts in the Allende meteorite. In addition to fullerenes, we detected many polycyclic aromatic hydrocarbons (PAHs) in the Allende meteorite, consistent with previous reports. In particular, we detected benzofluoranthene and corannulene (C20H10), five-membered ring structures which have been proposed as precursors to the formation of fullerene synthesis, perhaps within circumstellar envelopes or other sites in the interstellar medium.

Preparation and characterization of oriented poly(vinyl alcohol)/carbon nanotube composite nanofibers

NASA Astrophysics Data System (ADS)

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

2017-07-01

Oriented nanofiber mats blended with carbon nanotubes (CNTs) are expected to be applied as cell seeding scaffolds. Biomaterials that are often used for cell seeding scaffolds generally have low mechanical strength and low electrical conductivity; thus, it has been difficult to apply them to tissues such as heart and nerve. In this study, we prepared oriented poly(vinyl alcohol) (PVA) nanofiber mats blended with various CNT concentrations (up to 10 wt %) by electrospinning using the parallel plate electrodes as collectors with applied voltage. The morphology, mechanical properties, and electrical properties of the prepared oriented nanofiber mats were measured by using various techniques such as scanning electron microscopy (SEM). The tensile strength of the oriented nanofiber mats in the applied voltage direction increased from 2.5 to 9.7 MPa with CNT concentration. Furthermore, the electrical conductivity of the oriented nanofiber mats in the applied voltage direction increased from 0.67 × 10-7 to 4.3 × 10-7 S·m-1. Also, the mechanical strength and electrical conductivity of the oriented nanofiber mats in the applied voltage direction were 3-4 and 2-3 times higher than those in the perpendicular direction, respectively.

Combustion method for producing fullerenes

DOEpatents

Howard, Jack B.; McKinnon, J. Thomas

1993-01-01

A method for synthesizing fullerenes in flames is provided. Fullerenes are prepared by burning carbon-containing compounds in a flame and collecting the condensibles. The condensibles contain the desired fullerenes. Fullerene yields can be optimized and fullerene composition can be selectively varied. Fullerene yields and compositions are determined by selectively controlling flame conditions and parameters such as C/O ratio, pressure, temperature, residence time, diluent concentration and gas velocity.

Combustion method for producing fullerenes

DOEpatents

Howard, J.B.; McKinnon, J.T.

1993-12-28

A method for synthesizing fullerenes in flames is provided. Fullerenes are prepared by burning carbon-containing compounds in a flame and collecting the condensable. The condensable contain the desired fullerenes. Fullerene yields can be optimized and fullerene composition can be selectively varied. Fullerene yields and compositions are determined by selectively controlling flame conditions and parameters such as C/O ratio, pressure, temperature, residence time, diluent concentration and gas velocity. 4 figures.

Inorganic nanotubes and fullerenes . Structure and properties of hypothetical phosphorus fullerenes

NASA Astrophysics Data System (ADS)

Seifert, G.; Heine, T.; Fowler, P. W.

The possibility of stable non-carbon fullerenes is discussed for the case of phosphorus fullerene-like cage structures. On the basis of Density Functional Tight Binding calculations it is shown that many such cages correspond to metastable structures, but with increasing nuclearity become less stable with respect to separate molecular P4 units. Stability rules, known for carbon fullerenes, such as the ``isolated pentagon rule'', do not reflect the different electronic and steric requirements of the phosphorus atom. The computational results tend to rule out phosphorus fullerenes.

Potentiometric Urea Biosensor Based on an Immobilised Fullerene-Urease Bio-Conjugate

PubMed Central

Saeedfar, Kasra; Heng, Lee Yook; Ling, Tan Ling; Rezayi, Majid

2013-01-01

A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease) bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate) (PnBA) membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10−3 M to 8.28 × 10−5 M. The biosensor's sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor's response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days. PMID:24322561

Carbon nanofibers with highly dispersed tin and tin antimonide nanoparticles: Preparation via electrospinning and application as the anode materials for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Li, Zhi; Zhang, Jiwei; Shu, Jie; Chen, Jianping; Gong, Chunhong; Guo, Jianhui; Yu, Laigui; Zhang, Jingwei

2018-03-01

One-dimensional carbon nanofibers with highly dispersed tin (Sn) and tin antimonide (SnSb) nanoparticles are prepared by electrospinning in the presence of antimony-doped tin oxide (denoted as ATO) wet gel as the precursor. The effect of ATO dosage on the microstructure and electrochemical properties of the as-fabricated Sn-SnSb/C composite nanofibers is investigated. Results indicate that ATO wet gel as the precursor can effectively improve the dispersion of Sn nanoparticles in carbon fiber and prevent them from segregation during the electrospinning and subsequent calcination processes. The as-prepared Sn-SnSb/C nanofibers as the anode materials for lithium-ion batteries exhibit high reversible capacity and stable cycle performance. Particularly, the electrode made from Sn-SnSb/C composite nanofibers obtained with 0.9 g of ATO gel has a high specific capacity of 779 mAh·g-1 and 378 mAh·g-1 at the current density of 50 mA·g-1 and 5 A·g-1, respectively, and it exhibits a capacity retention of 97% after 1200 cycles under the current density of 1 A·g-1. This is because the carbon nanofibers can form a continuous conductive network to buffer the volume change of the electrodes while Sn and Sn-SnSb nanoparticles uniformly distributed in the carbon nanofibers are free of segregation, thereby contributing to electrochemical performances of the electrodes.

Conversion of fullerenes to diamond

DOEpatents

Gruen, Dieter M.

1994-01-01

A method of forming synthetic hydrogen defect free diamond or diamond like films on a substrate. The method involves providing vapor containing fullerene molecules with or without an inert gas, providing a device to impart energy to the fullerene molecules, fragmenting at least in part some of the fullerene molecules in the vapor or energizing the molecules to incipient fragmentation, ionizing the fullerene molecules, impinging ionized fullerene molecules on the substrate to assist in causing fullerene fragmentation to obtain a thickness of diamond on the substrate.

Enhanced superconductivity of fullerenes

DOEpatents

Washington, II, Aaron L.; Teprovich, Joseph A.; Zidan, Ragaiy

2017-06-20

Methods for enhancing characteristics of superconductive fullerenes and devices incorporating the fullerenes are disclosed. Enhancements can include increase in the critical transition temperature at a constant magnetic field; the existence of a superconducting hysteresis over a changing magnetic field; a decrease in the stabilizing magnetic field required for the onset of superconductivity; and/or an increase in the stability of superconductivity over a large magnetic field. The enhancements can be brought about by transmitting electromagnetic radiation to the superconductive fullerene such that the electromagnetic radiation impinges on the fullerene with an energy that is greater than the band gap of the fullerene.

A combination of CoO and Co nanoparticles supported on electrospun carbon nanofibers as highly stable air electrodes

NASA Astrophysics Data System (ADS)

Alegre, Cinthia; Busacca, Concetta; Di Blasi, Orazio; Antonucci, Vincenzo; Aricò, Antonino Salvatore; Di Blasi, Alessandra; Baglio, Vincenzo

2017-10-01

Bifunctional materials able to catalyze both the oxygen reduction (ORR) and the oxygen evolution (OER) reactions in alkaline media are still a challenge for the progress of energy conversion and storage devices such as metal-air batteries or unitized regenerative fuel cells. In this work, carbon nanofibers synthesized by electrospinning are modified with a combination of cobalt oxide and metallic cobalt (CoO-Co/CNF) and studied as a bifunctional air electrode for metal-air batteries. The performance of CoO-Co/CNF for both reactions is compared with state-of-the-art catalysts such as Pt/C and IrO2. The combination of cobalt oxide and metallic cobalt, finely distributed on the surface of graphitic carbon nanofibers, leads to a bifunctional catalyst with a half-wave potential for the ORR slightly better than Pt/C and a reversibility (ΔEOER-ORR) of 809 mV. The stability of CoO-Co/CNF is assessed by means of different stress tests: polarizations at high electrochemical potentials (2 V vs. RHE), rapid charge-discharge cycles at ±80 mA cm-2 and long durability tests by charging for 12 h at 60 mA cm-2 and discharging for 8 h at -80 mA cm-2. CoO-Co/CNF shows a remarkable stability, maintaining, at least, an 82% of its performance for the ORR after the stress tests, even when cycled for more than 100 h.

Cobalt/copper-decorated carbon nanofibers as novel non-precious electrocatalyst for methanol electrooxidation

PubMed Central

2014-01-01

In this study, Co/Cu-decorated carbon nanofibers are introduced as novel electrocatalyst for methanol oxidation. The introduced nanofibers have been prepared based on graphitization of poly(vinyl alcohol) which has high carbon content compared to many polymer precursors for carbon nanofiber synthesis. Typically, calcination in argon atmosphere of electrospun nanofibers composed of cobalt acetate tetrahydrate, copper acetate monohydrate, and poly(vinyl alcohol) leads to form carbon nanofibers decorated by CoCu nanoparticles. The graphitization of the poly(vinyl alcohol) has been enhanced due to presence of cobalt which acts as effective catalyst. The physicochemical characterization affirmed that the metallic nanoparticles are sheathed by thin crystalline graphite layer. Investigation of the electrocatalytic activity of the introduced nanofibers toward methanol oxidation indicates good performance, as the corresponding onset potential was small compared to many reported materials; 310 mV (vs. Ag/AgCl electrode) and a current density of 12 mA/cm2 was obtained. Moreover, due to the graphite shield, good stability was observed. Overall, the introduced study opens new avenue for cheap and stable transition metals-based nanostructures as non-precious catalysts for fuel cell applications. PMID:24387682

Synthesis and radiation resistance of fullerenes and fullerene derivatives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shilin, V. A., E-mail: shilin@pnpi.spb.ru; Lebedev, V. T.; Sedov, V. P.

2016-07-15

The parameters of an electric-arc facility for the synthesis of fullerenes and endohedral metallofullerenes are optimized. The resistance of C{sub 60} and C{sub 70} fullerenes and C{sub 60}(OH){sub 30} and C{sub 70}(OH){sub 30} fullerenols against neutron irradiation is studied. It is established that the radiation resistance of the fullerenes is higher than that of the fullerenols, but the radiation resistance of the Gd@C{sub 2n} endometallofullerenes is lower than that of the corresponding Gd@C{sub 2n}(OH){sub 38} fullerenols. The radiation resistance of mixtures of Me@C{sub 2n}(OH){sub 38} (Me = Gd, Tb, Sc, Fe, and Pr) endometallofullerenes with C{sub 60}(OH){sub 30} is determined.more » The factors affecting the radiation resistance of the fullerenes and fullerenols are discussed.« less

Conversion of fullerenes to diamonds

DOEpatents

Gruen, Dieter M.

1995-01-01

A method of forming synthetic diamond or diamond-like films on a substrate surface. The method involves the steps of providing a vapor selected from the group of fullerene molecules or an inert gas/fullerene molecule mixture, providing energy to the fullerene molecules consisting of carbon-carbon bonds, the energized fullerene molecules breaking down to form fragments of fullerene molecules including C.sub.2 molecules and depositing the energized fullerene molecules with C.sub.2 fragments onto the substrate with farther fragmentation occurring and forming a thickness of diamond or diamond-like films on the substrate surface.

Medicinal applications of fullerenes

PubMed Central

Bakry, Rania; Vallant, Rainer M; Najam-ul-Haq, Muhammad; Rainer, Matthias; Szabo, Zoltan; Huck, Christian W; Bonn, Günther K

2007-01-01

Fullerenes have attracted considerable attention in different fields of science since their discovery in 1985. Investigations of physical, chemical and biological properties of fullerenes have yielded promising information. It is inferred that size, hydrophobicity, three-dimensionality and electronic configurations make them an appealing subject in medicinal chemistry. Their unique carbon cage structure coupled with immense scope for derivatization make them a potential therapeutic agent. The study of biological applications has attracted increasing attention despite the low solubility of carbon spheres in physiological media. The fullerene family, and especially C60, has appealing photo, electrochemical and physical properties, which can be exploited in various medical fields. Fullerene is able to fit inside the hydrophobic cavity of HIV proteases, inhibiting the access of substrates to the catalytic site of enzyme. It can be used as radical scavenger and antioxidant. At the same time, if exposed to light, fullerene can produce singlet oxygen in high quantum yields. This action, together with direct electron transfer from excited state of fullerene and DNA bases, can be used to cleave DNA. In addition, fullerenes have been used as a carrier for gene and drug delivery systems. Also they are used for serum protein profiling as MELDI material for biomarker discovery. In this review we report the aspects of medicinal applications of fullerenes. PMID:18203430

Porous worm-like NiMoO4 coaxially decorated electrospun carbon nanofiber as binder-free electrodes for high performance supercapacitors and lithium-ion batteries

NASA Astrophysics Data System (ADS)

Tian, Xiaodong; Li, Xiao; Yang, Tao; Wang, Kai; Wang, Hongbao; Song, Yan; Liu, Zhanjun; Guo, Quangui

2018-03-01

The peculiar architectures consisting of electrospun carbon nanofibers coaxially decorated by porous worm-like NiMoO4 were successfully fabricated for the first time to address the poor cycling stability and inferior rate capability of the state-of-the-art NiMoO4-based electrodes caused by the insufficient structural stability, dense structure and low conductivity. The porous worm-like structure endows the electrode high capacitance/capacity due to large effective specific surface area and short electron/ion diffusion channels. Moreover, the robust integrated electrode with sufficient internal spaces can self-accommodate volume variation during charge/discharge processes, which is beneficial to the structural stability and integrity. By the virtue of rational design of the architecture, the hybrid electrode delivered high specific capacitance (1088.5 F g-1 at 1 A g-1), good rate capability (860.3 F g-1 at 20 A g-1) and long lifespan with a capacitance retention of 73.9% after 5000 cycles when used as supercapacitor electrode. For lithium-ion battery application, the electrode exhibited a high reversible capacity of 1132.1 mAh g-1 at 0.5 A g-1. Notably, 689.7 mAh g-1 can be achieved even after 150 continuous cycles at a current density of 1 A g-1. In the view of their outstanding electrochemical performance and the cost-effective fabrication process, the integrated nanostructure shows great promising applications in energy storage.

Vertically aligned carbon nanofiber as nano-neuron interface for monitoring neural function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ericson, Milton Nance; McKnight, Timothy E; Melechko, Anatoli Vasilievich

2012-01-01

Neural chips, which are capable of simultaneous, multi-site neural recording and stimulation, have been used to detect and modulate neural activity for almost 30 years. As a neural interface, neural chips provide dynamic functional information for neural decoding and neural control. By improving sensitivity and spatial resolution, nano-scale electrodes may revolutionize neural detection and modulation at cellular and molecular levels as nano-neuron interfaces. We developed a carbon-nanofiber neural chip with lithographically defined arrays of vertically aligned carbon nanofiber electrodes and demonstrated its capability of both stimulating and monitoring electrophysiological signals from brain tissues in vitro and monitoring dynamic information ofmore » neuroplasticity. This novel nano-neuron interface can potentially serve as a precise, informative, biocompatible, and dual-mode neural interface for monitoring of both neuroelectrical and neurochemical activity at the single cell level and even inside the cell.« less

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

NASA Astrophysics Data System (ADS)

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.

Robust electrodes based on coaxial TiC/C-MnO2 core/shell nanofiber arrays with excellent cycling stability for high-performance supercapacitors.

PubMed

Zhang, Xuming; Peng, Xiang; Li, Wan; Li, Limin; Gao, Biao; Wu, Guosong; Huo, Kaifu; Chu, Paul K

2015-04-17

A coaxial electrode structure composed of manganese oxide-decorated TiC/C core/shell nanofiber arrays is produced hydrothermally in a KMnO4 solution. The pristine TiC/C core/shell structure prepared on the Ti alloy substrate provides the self-sacrificing carbon shell and highly conductive TiC core, thus greatly simplifying the fabrication process without requiring an additional reduction source and conductive additive. The as-prepared electrode exhibits a high specific capacitance of 645 F g(-1) at a discharging current density of 1 A g(-1) attributable to the highly conductive TiC/C and amorphous MnO2 shell with fast ion diffusion. In the charging/discharging cycling test, the as-prepared electrode shows high stability and 99% capacity retention after 5000 cycles. Although the thermal treatment conducted on the as-prepared electrode decreases the initial capacitance, the electrode undergoes capacitance recovery through structural transformation from the crystalline cluster to layered birnessite type MnO2 nanosheets as a result of dissolution and further electrodeposition in the cycling. 96.5% of the initial capacitance is retained after 1000 cycles at high charging/discharging current density of 25 A g(-1). This study demonstrates a novel scaffold to construct MnO2 based SCs with high specific capacitance as well as excellent mechanical and cycling stability boding well for future design of high-performance MnO2-based SCs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly conductive electrospun carbon nanofiber/MnO2 coaxial nano-cables for high energy and power density supercapacitors

NASA Astrophysics Data System (ADS)

Zhi, Mingjia; Manivannan, Ayyakkannu; Meng, Fanke; Wu, Nianqiang

2012-06-01

This paper presents highly conductive carbon nanofiber/MnO2 coaxial cables in which individual electrospun carbon nanofibers are coated with an ultrathin hierarchical MnO2 layer. In the hierarchical MnO2 structure, an around 4 nm thick sheath surrounds the carbon nanofiber (CNF) in a diameter of 200 nm, and nano-whiskers grow radically outward from the sheath in view of the cross-section of the coaxial cables, giving a high specific surface area of MnO2. The CNFs are synthesized by electrospinning a precursor containing iron acetylacetonate (AAI). The addition of AAI not only enlarges the specific surface area of the CNF but also greatly enhances their electronic conductivity, which leads to a dramatic improvement in the specific capacitance and the rate capability of the CNF/MnO2 electrode. The AAI-CNF/MnO2 electrode shows a specific capacitance of 311 F g-1 for the whole electrode and 900 F g-1 for the MnO2 shell at a scan rate of 2 mV s-1. Good cycling stability, high energy density (80.2 Wh kg-1) and high power density (57.7 kW kg-1) are achieved. This work indicates that high electronic conductivity of the electrode material is crucial to achieving high power and energy density for pseudo-supercapacitors.

An Investigation of Electrochemomechanical Actuation of Conductive Polyacrylonitrile (PAN) Nanofiber Composites

NASA Astrophysics Data System (ADS)

Gonzalez, Mark A.

A polymer-based nanofiber composite actuator designed for linear actuation was fabricated by electrospinning, actuated by electrolysis, and characterized by electrical and mechanical testing to address performance limitations and understand the activation processing effects on actuation performance. Currently, Electroactive polymers (EAPs) have provided uses in sensory and actuation technology, but have either low force output or expand rather than contract, falling short in capturing the natural motion and function of muscle desperately needed to provide breakthroughs in the bio-medical and robotic fields. Previous research has shown activated Polyacrylonitrile (PAN) fibers having biomimetic functionalities similar to the sarcomere contraction responsible for muscle function. Activated PAN is also known to contract and expand by electrolysis when in close vicinity to the anode and cathode, respectively. PAN nanofibers especially show faster response to changes in environmental pH and improved mechanical properties over larger diameter fibers. Conductive additives were introduced to the electrospinning solution and activated in an attempt to create composite PAN nanofiber gel actuators with improved conductivity and eliminate the need of stiff electrodes. Tensile testing was conducted to examine changes in mechanical properties between annealing and hydrolysis processing. Introducing conductive additives did not show a significant increase in conductivity and created unusable samples, requiring alternative electrode materials. Electrochemical contraction rates up to 25%/ min were achieved. Strains of 58.8%, ultimate stresses up to 77.1 MPa, and moduli of 0.21 MPa were achieved with pure PAN nanofiber mats, surpassing mechanical properties of natural muscles. Improvements to contraction rates and young's moduli are necessary to capture the function and performance of skeletal muscles properly.

Preparation and characterization of poly(vinyl alcohol)/graphene nanofibers synthesized by electrospinning

NASA Astrophysics Data System (ADS)

Barzegar, Farshad; Bello, Abdulhakeem; Fabiane, Mopeli; Khamlich, Saleh; Momodu, Damilola; Taghizadeh, Fatemeh; Dangbegnon, Julien; Manyala, Ncholu

2015-02-01

We report on the synthesis and characterization of electrospun polyvinyl alcohol (PVA)/graphene nanofibers. The samples produced were characterized by Raman spectroscopy for structural and defect density analysis, scanning electron microscopy (SEM) for morphological analysis, and thermogravimetric (TGA) for thermal analysis. SEM measurements show uniform hollow PVA fibers formation and excellent graphene dispersion within the fibers, while TGA measurements show the improved thermal stability of PVA in the presence of graphene. The synthesized polymer reinforced nanofibers have potential to serve in many different applications such as thermal management, supercapacitor electrodes and biomedical materials for drug delivery.

Experimental and Theoretical Studies of Nanostructured Electrodes for Use in Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Gong, Jiawei

Among various photovoltaic technologies available in the emerging market, dye-sensitized solar cells (DSSCs) are deemed as an effective, competitive solution to the increasing demand for high-efficiency PV devices. To move towards full commercialization, challenges remain in further improvement of device stability as well as reduction of material and manufacturing costs. This study aims at rational synthesis and photovoltaic characterization of two nanostructured electrode materials (i.e. SnO2 nanofibers and activated graphene nanoplatelets) for use as photoanode and counter electrode in dye-sensitized solar cells. The main objective is to explore the favorable charge transport features of SnO2 nanofiber network and simultaneously replace the high-priced conventional electrocatalytic nanomaterials (e.g. Pt nanoparticles) used in existing counter electrode of DSSCs. To achieve this objective, a multiphysics model of electrode kinetics was developed to optimize various design parameters and cell configurations. The porous hollow SnO2 nanofibers were successfully synthesized via a facile route consisting of electrospinning precursor polymer nanofibers, followed by controlled carbonization. The novel SnO2/TiO2 composite photoanode materials carry advantages of SnO2 nanofiber network (e.g. nanostructural continuity, high electron mobility) and TiO2 nanoparticles (e.g. high specific area), and therefore show excellent photovoltaic properties including improved short-circuit current and fill factors. In addition, hydrothermally activated graphene nanoplatelets (aGNP) were used as a catalytic counter electrode material to substitute for conventionally used platinum nanoparticles. Improved catalytic performance of aGNP electrode was achieved through increased surface area and better control of morphology. Dye-sensitized solar cells using these aGNP electrodes had power conversion efficiencies comparable to those using platinum nanoparticles with I-/I3- redox mediators

Interaction between fullerenes and single-wall carbon nanotubes: the influence of fullerene size and electronic structure.

PubMed

Hao, Jian; Guan, Lunhui; Guo, Xihong; Lian, Yongfu; Zhao, Shixiong; Dong, Jinquan; Yang, Shangyuan; Zhang, Hong; Sun, Baoyun

2011-09-01

A series of fullerenes and endohedral metallofullerenes peapods have been synthesized by supercritical method in high filling rate. The interaction between SWNTs and various kinds of fullerenes (C60, C70, C78, C84) and metallofullerenes (Gd@C82, Er@C82, Ho@C82, Y@C82) has been further investigated. The slight blue shift of G-band in Raman spectra with respect to pristine SWNTs was attributed to the charge transfer from SWNTs to fullerenes cage. The obvious RBM shift strongly depended on the distance between the inner wall of the SWNTs and the fullerene cage and also partly associated with the electronic structure of the fullerene. These results indicated that the interaction between fullerenes and SWNTs, which was considered to be the van de walls interaction, can be influenced by the cage size and the kind of fullerenes.

Bulk-Type All-Solid-State Lithium-Ion Batteries: Remarkable Performances of a Carbon Nanofiber-Supported MgH2 Composite Electrode.

PubMed

Zeng, Liang; Ichikawa, Takayuki; Kawahito, Koji; Miyaoka, Hiroki; Kojima, Yoshitsugu

2017-01-25

Magnesium hydride, MgH 2 , a recently developed compound for lithium-ion batteries, is considered to be a promising conversion-type negative electrode material due to its high theoretical lithium storage capacity of over 2000 mA h g -1 , suitable working potential, and relatively small volume expansion. Nevertheless, it suffers from unsatisfactory cyclability, poor reversibility, and slow kinetics in conventional nonaqueous electrolyte systems, which greatly limit the practical application of MgH 2 . In this work, a vapor-grown carbon nanofiber was used to enhance the electrical conductivity of MgH 2 using LiBH 4 as the solid-state electrolyte. It shows that a reversible capacity of over 1200 mA h g -1 with an average voltage of 0.5 V (vs Li/Li + ) can be obtained after 50 cycles at a current density of 1000 mA g -1 . In addition, the capacity of MgH 2 retains over 1100 mA h g -1 at a high current density of 8000 mA g -1 , which indicates the possibility of using MgH 2 as a negative electrode material for high power and high capacity lithium-ion batteries in future practical applications. Moreover, the widely studied sulfide-based solid electrolyte was also used to assemble battery cells with MgH 2 electrode in the same system, and the electrochemical performance was as good as that using LiBH 4 electrolyte.

Is the 21-micron Feature Observed in Some Post-AGB Stars Caused by the Interaction Between Ti Atoms and Fullerenes?

NASA Technical Reports Server (NTRS)

Kimura, Yuki; Nuth, Joseph A. III; Ferguson, Frank T.

2005-01-01

Recent measurements of fullerenes and Ti atoms recorded in our laboratory have demonstrated the presence of an infrared feature near 21 pm. The feature observed has nearly the same shape and position as is observed for one of the most enigmatic features in post-asymptotic giant blanch (AGB) stars. In our experimental system large cage carbon particles, such as large fullerenes, were produced from CO gas by the Boudouard reaction. Large-cage carbon particles intermixed with Ti atoms were produced by the evaporation of a Ti metal wrapped carbon electrode in CO gas. The infrared spectra of large fullerenes interacting with Ti atoms show a characteristic feature at 20.3 micron that closely corresponds to the 20.1 micron feature observed in post-AGB stars. Both the lab- oratory and stellar spectra also show a small but significant peak at 19.0 micron, which is attributed to fullerenes. Here, we propose that the interaction between fullerenes and Ti atoms may be a plausible explanation for the 21-micron feature seen in some post-AGB stars.

Simultaneous determination of Cd(II) and Pb(II) by differential pulse anodic stripping voltammetry based on graphite nanofibers-Nafion composite modified bismuth film electrode.

PubMed

Li, Dongyue; Jia, Jianbo; Wang, Jianguo

2010-12-15

A bismuth-film modified graphite nanofibers-Nafion glassy carbon electrode (BiF/GNFs-NA/GCE) was constructed for the simultaneous determination of trace Cd(II) and Pb(II). The electrochemical properties and applications of the modified electrode were studied. Operational parameters such as deposition potential, deposition time, and bismuth ion concentration were optimized for the purpose of determination of trace metal ions in 0.10 M acetate buffer solution (pH 4.5). Under optimal conditions, based on three times the standard deviation of the baseline, the limits of detection were 0.09 μg L(-1) for Cd(II) and 0.02 μg L(-1) for Pb(II) with a 10 min preconcentration. In addition, the BiF/GNFs-NA/GCE displayed good reproducibility and selectivity, making it suitable for the simultaneous determination of Cd(II) and Pb(II) in real sample such as river water and human blood samples. Copyright © 2010 Elsevier B.V. All rights reserved.

Highly sensitive and selective determination of methylergometrine maleate using carbon nanofibers/silver nanoparticles composite modified carbon paste electrode.

PubMed

Kalambate, Pramod K; Rawool, Chaitali R; Karna, Shashi P; Srivastava, Ashwini K

2016-12-01

A highly sensitive and selective voltammetric method for determination of Methylergometrine maleate (MM) in pharmaceutical formulations, urine and blood serum samples has been developed based on enhanced electrochemical response of MM at carbon nanofibers and silver nanoparticles modified carbon paste electrode (CNF-AgNP-CPE). The electrode material was characterized by various techniques viz., X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic response of MM at CNF-AgNP-CPE was studied by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Under optimized conditions, the proposed sensor exhibits excellent electrochemical response towards MM. The DPV study shows greatly enhanced electrochemical signal for MM at CNF-AgNP-CPE lending high sensitivity to the proposed sensor for MM detection. The peak (Ip) current for MM is found to be rectilinear in the range 4.0×10(-8)-2.0×10(-5)M with a detection limit of 7.1×10(-9)M using DPV. The feasibility of the proposed sensor in analytical applications was investigated by conducting experiments on commercial pharmaceutical formulations, human urine and blood serum samples, which yielded satisfactory recoveries of MM. The proposed electrochemical sensor offers high sensitivity, selectivity, reproducibility and practical utility. We recommend it as an authentic and productive electrochemical sensor for successful determination of MM. Copyright © 2016. Published by Elsevier B.V.

Mesoporous orthorhombic Nb2O5 nanofibers as pseudocapacitive electrodes with ultra-stable Li storage characteristics

NASA Astrophysics Data System (ADS)

Cheong, Jun Young; Jung, Ji-Won; Youn, Doo-Young; Kim, Chanhoon; Yu, Sunmoon; Cho, Su-Ho; Yoon, Ki Ro; Kim, Il-Doo

2017-08-01

Ultra-stable pseudocapacitive electrodes for lithium-ion batteries (LIBs) are increasing in demand as highly sustainable energy storage system with excellent charge transport is important. The establishment of facile, controllable, and scalable synthesis of pseudocapacitive electrode materials is an attractive solution to realize such objectives. Here, we have successfully fabricated mesoporous orthorhombic Nb2O5 nanofibers (m-T-Nb2O5 NFs) by simple single-spinneret electrospinning followed by calcination at 600 °C. As-formed m-T-Nb2O5 NFs exhibit high surface area (23.7 m2 g-1) and a number of mesopores in the vacant sites where organic polymer was once decomposed. Such rationally designed m-T-Nb2O5-NFs allow facile Li ion and electron transport, with pseudocapacitive behavior. Arising from the high surface area coupled with mesopores in-between the Nb2O5 nanograins, it exhibits ultra-long cycle retention (a capacity of ∼160 mAh g-1 at 500 mA g-1 after 2000 cycles and ∼88 mAh g-1 at 3000 mA g-1 after 5000 cycles) and higher rate capability (∼70 mAh g-1 at 5000 mA g-1). Such cycle retention characteristics of m-T-Nb2O5-NFs are at least 100-fold slower capacity decay compared with previously reported one-dimensional (1D) Nb2O5 nanostructures and even superior or comparable to recently reported Nb2O5-graphene composite materials.

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

NASA Astrophysics Data System (ADS)

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

Development of Mass Spectrometric Ionization Methods for Fullerenes and Fullerene Derivatives

EPA Science Inventory

Currently investigations into the environmental behavior of fullerenes and fullerene derivatives is hampered by the lack of well characterized standards and by the lack of readily available quantitative analytical methods. Reported herein are investigations into the utility of ma...

Quasi 2D Mesoporous Carbon Microbelts Derived from Fullerene Crystals as an Electrode Material for Electrochemical Supercapacitors.

PubMed

Tang, Qin; Bairi, Partha; Shrestha, Rekha Goswami; Hill, Jonathan P; Ariga, Katsuhiko; Zeng, Haibo; Ji, Qingmin; Shrestha, Lok Kumar

2017-12-27

Fullerene C 60 microbelts were fabricated using the liquid-liquid interfacial precipitation method and converted into quasi 2D mesoporous carbon microbelts by heat treatment at elevated temperatures of 900 and 2000 °C. The carbon microbelts obtained by heat treatment of fullerene C 60 microbelts at 900 °C showed excellent electrochemical supercapacitive performance, exhibiting high specific capacitances ca. 360 F g -1 (at 5 mV s -1 ) and 290 F g -1 (at 1 A g -1 ) because of the enhanced surface area and the robust mesoporous framework structure. Additionally, the heat-treated carbon microbelt showed good rate performance, retaining 49% of capacitance at a high scan rate of 10 A g -1 . The carbon belts exhibit super cyclic stability. Capacity loss was not observed even after 10 000 charge/discharge cycles. These results demonstrate that the quasi 2D mesoporous carbon microbelts derived from a π-electron-rich carbon source, fullerene C 60 crystals, could be used as a new candidate material for electrochemical supercapacitor applications.

1.6 V nanogenerator for mechanical energy harvesting using PZT nanofibers.

PubMed

Chen, Xi; Xu, Shiyou; Yao, Nan; Shi, Yong

2010-06-09

Energy harvesting technologies that are engineered to miniature sizes, while still increasing the power delivered to wireless electronics, (1, 2) portable devices, stretchable electronics, (3) and implantable biosensors, (4, 5) are strongly desired. Piezoelectric nanowire- and nanofiber-based generators have potential uses for powering such devices through a conversion of mechanical energy into electrical energy. (6) However, the piezoelectric voltage constant of the semiconductor piezoelectric nanowires in the recently reported piezoelectric nanogenerators (7-12) is lower than that of lead zirconate titanate (PZT) nanomaterials. Here we report a piezoelectric nanogenerator based on PZT nanofibers. The PZT nanofibers, with a diameter and length of approximately 60 nm and 500 microm, were aligned on interdigitated electrodes of platinum fine wires and packaged using a soft polymer on a silicon substrate. The measured output voltage and power under periodic stress application to the soft polymer was 1.63 V and 0.03 microW, respectively.

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

PubMed

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.

The topology of fullerenes

PubMed Central

Schwerdtfeger, Peter; Wirz, Lukas N; Avery, James

2015-01-01

Fullerenes are carbon molecules that form polyhedral cages. Their bond structures are exactly the planar cubic graphs that have only pentagon and hexagon faces. Strikingly, a number of chemical properties of a fullerene can be derived from its graph structure. A rich mathematics of cubic planar graphs and fullerene graphs has grown since they were studied by Goldberg, Coxeter, and others in the early 20th century, and many mathematical properties of fullerenes have found simple and beautiful solutions. Yet many interesting chemical and mathematical problems in the field remain open. In this paper, we present a general overview of recent topological and graph theoretical developments in fullerene research over the past two decades, describing both solved and open problems. WIREs Comput Mol Sci 2015, 5:96–145. doi: 10.1002/wcms.1207 Conflict of interest: The authors have declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website. PMID:25678935

Carbon Nanofiber Nanoelectrodes for Biosensing Applications

NASA Technical Reports Server (NTRS)

Koehne, Jessica Erin

2014-01-01

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 two studies using vertically aligned CNF nanoelectrodes for biomedical applications. CNF arrays are investigated as neural stimulation and neurotransmitter recording electrodes for application in deep brain stimulation (DBS). Polypyrrole coated CNF nanoelectrodes have shown great promise as stimulating electrodes due to their large surface area, low impedance, biocompatibility and capacity for highly localized stimulation. CNFs embedded in SiO2 have been used as sensing electrodes for neurotransmitter detection. 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.

Fullerenes formation in flames

NASA Technical Reports Server (NTRS)

Howard, Jack B.

1993-01-01

Fullerenes are composed of carbon atoms arranged in approximately spherical or ellipsoidal cages resembling the geodesic domes designed by Buckminster Fuller, after whom the molecules were named. The approximately spherical fullerene, which resembles a soccer ball and contains sixty atoms (C60), is called buckminsterfullerene. The fullerene containing seventy carbon atoms (C70) is approximately ellipsoidal, similar to a rugby ball. Fullerenes were first detected in 1985, in carbon vapor produced by laser evaporation of graphite. The closed shell structure, which has no edge atoms vulnerable to reaction, was proposed to explain the observed high stability of certain carbon clusters relative to that of others at high temperatures and in the presence of an oxidizing gas.

Fullerene nanomaterials potentiate hair growth.

PubMed

Zhou, Zhiguo; Lenk, Robert; Dellinger, Anthony; MacFarland, Darren; Kumar, Krishan; Wilson, Stephen R; Kepley, Christopher L

2009-06-01

Hair loss is a common symptom resulting from a wide range of disease processes and can lead to stress in affected individuals. The purpose of this study was to examine the effect of fullerene nanomaterials on hair growth. We used shaved mice as well as SKH-1 "bald" mice to determine if fullerene-based compounds could affect hair growth and hair follicle numbers. In shaved mice, fullerenes increase the rate of hair growth as compared with mice receiving vehicle only. In SKH-1 hairless mice fullerene derivatives given topically or subdermally markedly increased hair growth. This was paralleled by a significant increase in the number of hair follicles in fullerene-treated mice as compared with those mice treated with vehicle only. The fullerenes also increased hair growth in human skin sections maintained in culture. These studies have wide-ranging implications for those conditions leading to hair loss, including alopecia, chemotherapy, and reactions to various chemicals.

Improved conversion efficiency in dye-sensitized solar cells based on electrospun Al-doped ZnO nanofiber electrodes prepared by seed layer treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yun Sining, E-mail: alexsyun1974@yahoo.com.c; Lim, Sangwoo

2011-02-15

The application of electrospun nanofibers in electronic devices is limited due to their poor adhesion to conductive substrates. To improve this, a seed layer (SD) is introduced on the FTO substrate before the deposition of the electrospun composite nanofibers. This facilitates the release of interfacial tensile stress during calcination and enhances the interfacial adhesion of the AZO nanofiber films with the FTO substrate. Dye-sensitized solar cells (DSSC) based on these AZO nanofiber photoelectrodes have been fabricated and investigated. An energy conversion efficiency ({eta}) of 0.54-0.55% has been obtained under irradiation of AM 1.5 simulated sunlight (100 mW/cm{sup 2}), indicating amore » massive improvement of {eta} in the AZO nanofiber film DSSCs after SD-treatment of the FTO substrate as compared to those with no treatment. The SD-treatment has been demonstrated to be a simple and facile method to solve the problem of poor adhesion between electrospun nanofibers and the conductive substrate. -- Graphical abstract: The poor adhesion between electrospun nanofibers and substrate is improved by a simple and facile seed layer (SD) treatment. The energy conversion efficiency of AZO nanofiber-based DSSCs has been greatly increased by SD-treatment of the FTO substrate. Display Omitted Research highlights: {yields} A simple and facile method (SD-treatment) has been demonstrated. {yields} The poor adhesion between electrospun nanofibers and substrate is improved by the SD-treatment. {yields} The {eta} of AZO nanofiber-based DSSCs has been greatly improved by SD-treatment of the FTO substrate.« less

Diamond film growth from fullerene precursors

DOEpatents

Gruen, Dieter M.; Liu, Shengzhong; Krauss, Alan R.; Pan, Xianzheng

1997-01-01

A method and system for manufacturing diamond film. The method involves forming a fullerene vapor, providing a noble gas stream and combining the gas with the fullerene vapor, passing the combined fullerene vapor and noble gas carrier stream into a chamber, forming a plasma in the chamber causing fragmentation of the fullerene and deposition of a diamond film on a substrate.

Observation of an all-boron fullerene

NASA Astrophysics Data System (ADS)

Zhai, Hua-Jin; Zhao, Ya-Fan; Li, Wei-Li; Chen, Qiang; Bai, Hui; Hu, Han-Shi; Piazza, Zachary A.; Tian, Wen-Juan; Lu, Hai-Gang; Wu, Yan-Bo; Mu, Yue-Wen; Wei, Guang-Feng; Liu, Zhi-Pan; Li, Jun; Li, Si-Dian; Wang, Lai-Sheng

2014-08-01

After the discovery of fullerene-C60, it took almost two decades for the possibility of boron-based fullerene structures to be considered. So far, there has been no experimental evidence for these nanostructures, in spite of the progress made in theoretical investigations of their structure and bonding. Here we report the observation, by photoelectron spectroscopy, of an all-boron fullerene-like cage cluster at B40- with an extremely low electron-binding energy. Theoretical calculations show that this arises from a cage structure with a large energy gap, but that a quasi-planar isomer of B40- with two adjacent hexagonal holes is slightly more stable than the fullerene structure. In contrast, for neutral B40 the fullerene-like cage is calculated to be the most stable structure. The surface of the all-boron fullerene, bonded uniformly via delocalized σ and π bonds, is not perfectly smooth and exhibits unusual heptagonal faces, in contrast to C60 fullerene.

Observation of an all-boron fullerene.

PubMed

Zhai, Hua-Jin; Zhao, Ya-Fan; Li, Wei-Li; Chen, Qiang; Bai, Hui; Hu, Han-Shi; Piazza, Zachary A; Tian, Wen-Juan; Lu, Hai-Gang; Wu, Yan-Bo; Mu, Yue-Wen; Wei, Guang-Feng; Liu, Zhi-Pan; Li, Jun; Li, Si-Dian; Wang, Lai-Sheng

2014-08-01

After the discovery of fullerene-C60, it took almost two decades for the possibility of boron-based fullerene structures to be considered. So far, there has been no experimental evidence for these nanostructures, in spite of the progress made in theoretical investigations of their structure and bonding. Here we report the observation, by photoelectron spectroscopy, of an all-boron fullerene-like cage cluster at B40(-) with an extremely low electron-binding energy. Theoretical calculations show that this arises from a cage structure with a large energy gap, but that a quasi-planar isomer of B40(-) with two adjacent hexagonal holes is slightly more stable than the fullerene structure. In contrast, for neutral B40 the fullerene-like cage is calculated to be the most stable structure. The surface of the all-boron fullerene, bonded uniformly via delocalized σ and π bonds, is not perfectly smooth and exhibits unusual heptagonal faces, in contrast to C60 fullerene.

Diamond film growth from fullerene precursors

DOEpatents

Gruen, D.M.; Liu, S.; Krauss, A.R.; Pan, X.

1997-04-15

A method and system are disclosed for manufacturing diamond film. The method involves forming a fullerene vapor, providing a noble gas stream and combining the gas with the fullerene vapor, passing the combined fullerene vapor and noble gas carrier stream into a chamber, forming a plasma in the chamber causing fragmentation of the fullerene and deposition of a diamond film on a substrate. 10 figs.

Process for fullerene functionalization

DOEpatents

Cahill, Paul A.; Henderson, Craig C.

1995-01-01

Di-addended and tetra-addended Buckminster fullerenes are synthesized through the use of novel organoborane intermediates. The C.sub.60, C.sub.70, or higher fullerene is reacted with a borane such as BH.sub.3 in a solvent such as toluene to form an organoborane intermediate. Reaction of the organoborane such as hydrolysis with water or alcohol results in the product di-addended and tetra-addended fullerene in up to 30% yields. Dihydrofullerenes and tetrahydrofullerenes are produced by the process of the invention.

Process for fullerene functionalization

DOEpatents

Cahill, P.A.; Henderson, C.C.

1995-12-12

Di-addended and tetra-addended Buckminster fullerenes are synthesized through the use of novel organoborane intermediates. The C{sub 60}, C{sub 70}, or higher fullerene is reacted with a borane such as BH{sub 3} in a solvent such as toluene to form an organoborane intermediate. Reaction of the organoborane such as hydrolysis with water or alcohol results in the product di-addended and tetra-addended fullerene in up to 30% yields. Dihydrofullerenes and tetrahydrofullerenes are produced by the process of the invention. 7 figs.

Production of fullerenic nanostructures in flames

DOEpatents

Howard, Jack B.; Vander Sande, John B.; Chowdhury, K. Das

1999-01-01

A method for the production of fullerenic nanostructures is described in which unsaturated hydrocarbon fuel and oxygen are combusted in a burner chamber at a sub-atmospheric pressure, thereby establishing a flame. The condensibles of the flame are collected at a post-flame location. The condensibles contain fullerenic nanostructures, such as single and nested nanotubes, single and nested nanoparticles and giant fullerenes. The method of producing fullerenic soot from flames is also described.

Production Of Fullerenic Soot In Flames

DOEpatents

Howard, Jack B.; Vander Sande, John B.; Chowdhury, K. Das

2000-12-19

A method for the production of fullerenic nanostructures is described in which unsaturated hydrocarbon fuel and oxygen are combusted in a burner chamber at a sub-atmospheric pressure, thereby establishing a flame. The condensibles of the flame are collected at a post-flame location. The condensibles contain fullerenic nanostructures, such as single and nested nanotubes, single and nested nanoparticles and giant fullerenes. The method of producing fullerenic soot from flames is also described.

Highly porous 3D nanofiber scaffold using an electrospinning technique.

PubMed

Kim, Geunhyung; Kim, WanDoo

2007-04-01

A successful 3D tissue-engineering scaffold must have a highly porous structure and good mechanical stability. High porosity and optimally designed pore size provide structural space for cell accommodation and migration and enable the exchange of nutrients between the scaffold and environment. Poly(epsilon-carprolactone) fibers were electrospun using an auxiliary electrode and chemical blowing agent (BA), and characterized according to porosity, pore size, and their mechanical properties. We also investigated the effect of the BA on the electrospinning processability. The growth characteristic of human dermal fibroblasts cells cultured in the webs showed the good adhesion with the blown web relative to a normal electrospun mat. The blown nanofiber web had good tensile properties and high porosity compared to a typical electrospun nanofiber scaffold. (c) 2006 Wiley Periodicals, Inc.

Generation of singlet oxygen in fullerene-containing media: 2. Fullerene-containing solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bagrov, I V; Belousova, I M; Grenishin, A S

2008-03-31

The generation of singlet oxygen in fullerene solutions is studied by luminescence methods upon excitation by pulsed, repetitively pulsed, and continuous radiation sources. The concentration of singlet oxygen in solutions is measured in stationary and pulsed irradiation regimes. The rate constants of quenching of O{sub 2}({sup 1}{delta}{sub g}) by fullerenes C{sub 70} and C{sub 60} in the CCl{sub 4} solution are measured to be (7.2{+-}0.1)x10{sup 7} L mol{sup -1} s{sup -1} and less than 6x10{sup 4} L mol{sup -1} s{sup -1}, respectively. The temperature and photolytic variations in the generation properties of the fullerene solution exposed to intense continuous radiationmore » are studied by the methods of optical and EPR spectroscopy. Pulsed irradiation resulted in the production of singlet oxygen in suspensions of fullerene-like structures, in particular, astralenes. A liquid pulsed singlet-oxygen generator based on the fullerene solution in CCl{sub 4} is developed and studied, in which the yield of O{sub 2} ({sup 1}{delta}{sub g}) to the gas phase at concentrations up to 5x10{sup 16} cm{sup -3} is obtained. (laser applications and other topics in quantum electronics)« less

Fullerene formation and annealing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mintmire, J.W.

1996-04-05

Why does the highly symmetric carbon cluster C{sub 60} form in such profusion under the right conditions? This question was first asked in 1985, when Kroto suggested that the predominance of the C{sub 60} carbon clusters observed in the molecular beam experiments could be explained by the truncated icosahedral (or soccer ball) form. The name given to this cluster, buckminsterfullerene, led to the use of the term fullerenes for the family of hollow-cage carbon clusters made up of even numbers of triply coordinated carbons arranged with 12 pentagonal rings and an almost arbitrary number of hexagonal rings. More than amore » decade later, we still lack a completely satisfying understanding of the fundamental chemistry that takes place during fullerene formation. Most current models for fullerene formation require a facile mechanism for ring rearrangement in the fullerene structure, but the simplest proposed mechanisms are believed to have unrealistically high activation barriers. In recent research calculations have suggested that atomic carbon in the reaction mixture could act as a catalyst and allow substantially lower activation barriers for fullerene annealing. This article discusses the background for this research and other adjunct research. 14 refs.« less

Interstellar fullerene compounds and diffuse interstellar bands

NASA Astrophysics Data System (ADS)

Omont, Alain

2016-05-01

Recently, the presence of fullerenes in the interstellar medium (ISM) has been confirmed and new findings suggest that these fullerenes may possibly form from polycyclic aromatic hydrocarbons (PAHs) in the ISM. Moreover, the first confirmed identification of two strong diffuse interstellar bands (DIBs) with the fullerene, C60+, connects the long standing suggestion that various fullerenes could be DIB carriers. These new discoveries justify reassessing the overall importance of interstellar fullerene compounds, including fullerenes of various sizes with endohedral or exohedral inclusions and heterofullerenes (EEHFs). The phenomenology of fullerene compounds is complex. In addition to fullerene formation in grain shattering, fullerene formation from fully dehydrogenated PAHs in diffuse interstellar clouds could perhaps transform a significant percentage of the tail of low-mass PAH distribution into fullerenes including EEHFs. But many uncertain processes make it extremely difficult to assess their expected abundance, composition and size distribution, except for the substantial abundance measured for C60+. EEHFs share many properties with pure fullerenes, such as C60, as regards stability, formation/destruction and chemical processes, as well as many basic spectral features. Because DIBs are ubiquitous in all lines of sight in the ISM, we address several questions about the interstellar importance of various EEHFs, especially as possible carriers of diffuse interstellar bands. Specifically, we discuss basic interstellar properties and the likely contributions of fullerenes of various sizes and their charged counterparts such as C60+, and then in turn: 1) metallofullerenes; 2) heterofullerenes; 3) fulleranes; 4) fullerene-PAH compounds; 5) H2@C60. From this reassessment of the literature and from combining it with known DIB line identifications, we conclude that the general landscape of interstellar fullerene compounds is probably much richer than heretofore realized

Ultrasonic-assisted deacetylation of cellulose acetate nanofibers: A rapid method to produce cellulose nanofibers.

PubMed

Ahmed, Farooq; Ayoub Arbab, Alvira; Jatoi, Abdul Wahab; Khatri, Muzamil; Memon, Najma; Khatri, Zeeshan; Kim, Ick Soo

2017-05-01

Herein we report a rapid method for deacetylation of cellulose acetate (CA) nanofibers in order to produce cellulose nanofibers using ultrasonic energy. The CA nanofibers were fabricated via electrospinning thereby treated with NaOH and NaOH/EtOH solutions at various pH levels for 30, 60 and 90min assisted by ultrasonic energy. The nanofiber webs were optimized by degree of deacetylation (DD%) and wicking behavior. The resultant nanofibers were further characterized by FTIR, SEM, WAXD, DSC analysis. The DD% and FTIR results confirmed a complete conversion of CA nanofibers to cellulose nanofibers within 1h with substantial increase of wicking height. Nanofibers morphology under SEM showed slightly swelling and no damage of nanofibers observed by use of ultrasonic energy. The results of ultrasonic-assisted deacetylation are comparable with the conventional deacetylation. Our rapid method offers substantially reduced deacetylation time from 30h to just 1h, thanks to the ultrasonic energy. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication and electrochemical properties of insoluble fullerene-diamine adduct thin-films as buffer layer by alternate immersion process

NASA Astrophysics Data System (ADS)

Saito, Jo; Akiyama, Tsuyoshi; Suzuki, Atsushi; Oku, Takeo

2017-01-01

Insoluble fullerene-diamine adduct thin-films consisting of C60 and 1,2-diaminoethane were easily fabricated on an electrode by an alternate immersion process. Formation of the C60-diamine adduct films were confirmed using transmission absorption spectroscopy and atomic force microscopy. An inverted-type organic solar cells were fabricated by using the C60-diamine adduct film as the electron transport layer. The resultant photoelectric conversation performance of the solar cells suggested that photocurrent is generated via the photoexcitation of polythiophene. The result suggests that the present insoluble fullerene-diamine adduct films worked as buffer layer for organic thin-film solar cells.

Impedimetric PSA aptasensor based on the use of a glassy carbon electrode modified with titanium oxide nanoparticles and silk fibroin nanofibers.

PubMed

Benvidi, Ali; Banaei, Maryam; Tezerjani, Marzieh Dehghan; Molahosseini, Hosein; Jahanbani, Shahriar

2017-12-14

This article describes an impedimetric aptasensor for the prostate specific antigen (PSA), a widely accepted prostate cancer biomarker. A glassy carbon electrode (GCE) was modified with titanium oxide nanoparticles (TiO 2 ) and silk fibroin nanofiber (SF) composite. The aptasensor was obtained by immobilizing a PSA-binding aptamer on the AuNP-modified with 6-mercapto-1-hexanol. The single fabrication steps were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The assay has two linear response ranges (from 2.5 fg.mL -1 to 25 pg.mL -1 , and from 25 pg.mL -1 to 25 ng.mL -1 ) and a 0.8 fg.mL -1 detection limit. After optimization of experimental conditions, the sensor is highly selective for PSA over bovine serum albumin and lysozyme. It was successfully applied to the detection of PSA in spiked serum samples. Graphical abstract Schematic of the fabrication of an aptasensor for the prostate specific antigen (PSA). It is based on the use of a glassy carbon electrode modified with gold nanoparticles and titanium oxide-silk fibroin. The immobilization process of aptamer and interaction with PSA were followed by electrochemical impedance spectroscopy technique.

Growth of TiO2 nanofibers on FTO substrates and their application in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Suryana, R.; Rahmawati, L. R.; Triyana, K.

2016-11-01

Growth of TiO2 nanofibers on fluorine-doped tin oxide (FTO) substrates have been performed using electrospinning method. Homogenous TiO2 solution as nanofibers material was prepared with titanium tetraisopropoxide (TTIP), ethanol, acetic acid and polyvinyl pyrrolidone (PVP) which was stirred for 24 h. TiO2 solution was loaded into the syringe pump. Electrospun voltage was operated under 15 kV with optimum distance between syringe tip and collector was 15 cm. FTO substrates were attached on the collector surface. Electrospinning coating time was varied at 15 min, 30 min, 45 min, and 60 min. Then TiO2 nanofibers layer was annealed at temperature of 450° C for 3 h. X-ray diffraction spectrum of TiO2 nanofibers showed major anatase peaks at 25.3°, 48.0° and 37.8° correlating crystal orientation of (101), (200), and (004), respectively while only one rutile peak at 27.5°(110). TiO2 nanofibers diameter was measured using atomic force microscopy (AFM). TiO2 nanofibers have diameter in range of 100-1000 nm. The obtained-TiO2 nanofibers were applied in dye-sensitized solar cell (DSSC) with beta-carotene as dye, carbon as catalyst, and I-/I3- redox couple as electrolyte. DSSC performance was analyzed from I-V characterization. Growth of TiO2 nanofibers at electrospinning time for 45 min has highest efficiency that is 0.016%. It is considered that TiO2 nanofibers at electrospinning time for 45 min can produce optimum thickness so that it is speculated many dyes adsorb on the nanofiber surfaces and many electrons diffuse toward the electrodes.

Fullerene reinforced ionic polymer transducer

NASA Astrophysics Data System (ADS)

Jung, J. H.; Cheng, T. H.; Oh, I. K.

2009-07-01

Novel fullerene reinforced nano-composite transducers based on nafion were developed inorder to improve the ionic polymer metal composite transducer. The fullerene reinforced nano-composite membranes were fabricated by recasting method with 0.1 and 0.5 weight percentage of a Fullerenes. Stress-Strain tests showed tremendous increase in stiffness and modulus of the nano-composite membranes even at these minute concentrations of Fullerenes. Ionic exchange capacity analysis and proton conductivity test were performed to calculate the electrical property of the composite films. Water uptake was measured to understand the liquid adsorbing characteristics of the membranes. Also, tip displacement of the nano-composite membrane transducer was investigated under AC excitations with various magnitudes and frequencies. Furthermore, the generated energy was measured from external sinusoidal physical input vibration with several displacements and frequencies by using a mechanical shaker. As a result, the fullerene reinforced nanocomposite membrane based on nafion shows higher stiffness and Young's modulus than that of pure nafion membrane. Also, the nano-composite membrane had better water uptake and proton conductivity than the pure membrane. Fullerene reinforced nano-composite membrane transducer actuates to a much larger deformations than pure nafion membrane transducer. The developed membrane transducer dissipates more energy from the physical input vibration than that of unfilled(or virgin) Nafion membrane transducer.

General synthesis of hierarchical C/MOx@MnO2 (M=Mn, Cu, Co) composite nanofibers for high-performance supercapacitor electrodes.

PubMed

Nie, Guangdi; Lu, Xiaofeng; Chi, Maoqiang; Gao, Mu; Wang, Ce

2018-01-01

Improving the conductivity and specific surface area of electrospun carbon nanofibers (CNFs) is beneficial to a rapid realization of their applications in energy storage field. Here, a series of one-dimensional C/MO x (M=Mn, Cu, Co) nanostructures are first prepared by a simple two-step process consisting of electrospinning and thermal treatment. The presence of low-valence MO x enhances the porosity and conductivity of nanocomposites to some extent through expanding graphitic domains or mixing metallic Cu into the CNF substrates. Next, the C/MO x frameworks are coated with MnO 2 nanosheets/nanowhiskers (C/MO x @MnO 2 ), during which process the low-valence MO x can partly reduce KMnO 4 so as to mitigate the consumption of CNFs. When used as active materials for supercapacitor electrodes, the obtained C/MO x @MnO 2 exhibit excellent electrochemical performances in comparison with the common CNFs@MnO 2 (CM) core-shell electrode due to the combination of desired functions of the individual components and the introduction of extra synergistic effect. It is believed that these results will provide an alternative way to further increase the capacitive properties of CNFs- or metal oxide-based nanomaterials and potentially stimulate the investigation on other kinds of C/MO x composite nanostructures for various applications. Copyright © 2017 Elsevier Inc. All rights reserved.

Toxicological Effects of Fullerenes on Caenorhabditis elegans

NASA Astrophysics Data System (ADS)

Schomaker, Justin; Snook, Renee; Howell, Carina

2014-03-01

The nematode species Caenorhabditis elegans is a useful genetic model organism due to its simplicity and the substantial molecular, genetic, and developmental knowledge about the species. In this study, this species was used to test the toxicological effects of C60 fullerene nanoparticles. In previous studies using rats, a solution of C60 fullerenes in olive oil proved to extend the life of the subjects. The purpose of this experiment was to subject C. elegans to varying concentrations of C60 fullerenes and observe their toxicological effects. Initial findings indicate a link between fullerene exposure and enlargement of the vulva as well as the formation of a small nodule at the base of the tail in some individuals. While the fullerenes are not lethally toxic in C. elegans, results will be presented that pertain to changes in life span and progeny of the nematodes exposed to varying concentrations of fullerenes as well as the mechanisms of toxicity. High magnification imaging via SEM and/or AFM will be used to characterize the fullerene nanoparticles. Testing the toxicity of fullerenes in a wide variety of organisms will lead to a more complete understanding of the effects of fullerenes on living organisms to ultimately understand their effects in humans. This work was supported by National Science Foundation grants DUE-1058829, DMR-0923047, DUE-0806660 and Lock Haven FPDC grants.

A novel and simple strategy for simultaneous determination of dopamine, uric acid and ascorbic acid based on the stacked graphene platelet nanofibers/ionic liquids/chitosan modified electrode.

PubMed

Niu, Xiuli; Yang, Wu; Guo, Hao; Ren, Jie; Yang, Fusheng; Gao, Jinzhang

2012-09-15

A promising electrochemical sensor for simultaneous determination of dopamine (DA), uric acid (UA) and ascorbic acid (AA) was fabricated based on the stacked graphene platelet nanofibers (SGNF)/ionic liquid (IL)/chitosan (CS) modified electrode. The SGNF/IL/CS modified electrode possessed excellent electrocatalytic activity towards the oxidation of DA, UA and AA with obvious reduction of over-potential and increased peak current, and the separations of oxidation peak potentials of DA-UA, DA-AA, and UA-AA were of 151, 213 and 364 mV, respectively. Under the optimum conditions, the linear range for the detection of DA, UA and AA were 0.05-240, 0.12-260, and 30-350 μM with the lowest detection limits of 0.05, 0.10 and 14.8 μM for DA, UA and AA, respectively. In addition, the electrochemical sensor showed high sensitivity, excellent selectivity, reproducibility and long-term stability. Copyright © 2012 Elsevier B.V. All rights reserved.

30 years of cosmic fullerenes

NASA Astrophysics Data System (ADS)

Berné, O.; Montillaud, J.; Mulas, G.; Joblin, C.

2015-12-01

In 1985, ``During experiments aimed at understanding the mechanisms by which long-chain carbon molecules are formed in interstellar space and circumstellar shells'', Harry Kroto and his collaborators serendipitously discovered a new form of carbon: fullerenes. The most emblematic fullerene (i.e. C_{60} ``buckminsterfullerene''), contains exactly 60 carbon atoms organized in a cage-like structure similar to a soccer ball. Since their discovery impacted the field of nanotechnologies, Kroto and colleagues received the Nobel prize in 1996. The cage-like structure, common to all fullerene molecules, gives them unique properties, in particular an extraordinary stability. For this reason and since they were discovered in experiments aimed to reproduce conditions in space, fullerenes were sought after by astronomers for over two decades, and it is only recently that they have been firmly identified by spectroscopy, in evolved stars and in the interstellar medium. This identification offered the opportunity to study the molecular physics of fullerenes in the unique physical conditions provided by space, and to make the link with other large carbonaceous molecules thought to be present in space : polycyclic aromatic hydrocarbons.

Fullerenic structures and such structures tethered to carbon materials

DOEpatents

Goel, Anish; Howard, Jack B.; Vander Sande, John B.

2010-01-05

The fullerenic structures include fullerenes having molecular weights less than that of C.sub.60 with the exception of C.sub.36 and fullerenes having molecular weights greater than C.sub.60. Examples include fullerenes C.sub.50, C.sub.58, C.sub.130, and C.sub.176. Fullerenic structure chemically bonded to a carbon surface is also disclosed along with a method for tethering fullerenes to a carbon material. The method includes adding functionalized fullerene to a liquid suspension containing carbon material, drying the suspension to produce a powder, and heat treating the powder.

Fullerenic structures and such structures tethered to carbon materials

DOEpatents

Goel, Anish; Howard, Jack B.; Vander Sande, John B.

2012-10-09

The fullerenic structures include fullerenes having molecular weights less than that of C.sub.60 with the exception of C.sub.36 and fullerenes having molecular weights greater than C.sub.60. Examples include fullerenes C.sub.50, C.sub.58, C.sub.130, and C.sub.176. Fullerenic structure chemically bonded to a carbon surface is also disclosed along with a method for tethering fullerenes to a carbon material. The method includes adding functionalized fullerene to a liquid suspension containing carbon material, drying the suspension to produce a powder, and heat treating the powder.

Production of fullerenes with concentrated solar flux

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hale, M. J.; Fields, C.; Lewandowski, A.

1994-01-01

Research at the National Renewable Energy Laboratory (NREL) has demonstrated that fullerenes can be produced using highly concentrated sunlight from a solar furnace. Since they were first synthesized in 1989, fullerenes have been the subject of intense research. They show considerable commercial potential in advanced materials and have potential applications that include semiconductors, superconductors, high-performance metals, and medical technologies. The most common fullerene is C{sub 60}, which is a molecule with a geometry resembling a soccer ball. Graphite vaporization methods such as pulsed-laser vaporization, resistive heating, and carbon arc have been used to produce fullerenes. None of these, however, seemsmore » capable of producing fullerenes economically on a large scale. The use of concentrated sunlight may help avoid the scale-up limitations inherent in more established production processes. Recently, researchers at NREL made fullerenes in NREL`s 10 kW High Flux Solar Furnace (HFSF) with a vacuum reaction chamber designed to deliver a solar flux of 1200 W/cm{sup 2} to a graphite pellet. Analysis of the resulting carbon soot by mass spectrometry and high-pressure liquid chromatography confirmed the existence of fullerenes. These results are very encouraging and we are optimistic that concentrated solar flux can provide a means for large-scale, economical production of fullerenes. This paper presents our method, experimental apparatus, and results of fullerene production research performed with the HFSF.« less

Binder-free three-dimensional high energy density electrodes for ionic-liquid supercapacitors.

PubMed

Tran, Chau; Lawrence, Daniel; Richey, Francis W; Dillard, Caitlin; Elabd, Yossef A; Kalra, Vibha

2015-09-18

We demonstrate a facile methodology to fabricate binder-free porous carbon nanofiber electrodes for room temperature ionic-liquid supercapacitors. The device provides an energy density of 80 W h kg(-1) based on the mass of two electrodes while retaining the high rate capability of supercapacitors with near-ideal CV curves at a high scan rate of 200 mV s(-1).

An electrospun nanofiber matrix based on organo-clay for biosensors: PVA/PAMAM-Montmorillonite

NASA Astrophysics Data System (ADS)

Unal, Betul; Yalcinkaya, Esra Evrim; Demirkol, Dilek Odaci; Timur, Suna

2018-06-01

Diagnostic techniques based on biomolecules have huge a potential to be applied in the application in various areas such as food/beverage industries, diseases diagnostics, monitoring of bio-processes and environmental pollutants. Immobilization of biomolecules on a transducer is the key parameter to being able to prepare a highly stable diagnostic tests. Electrospun nanofibers are a good alternative to immobilize biomolecules. Here, electrospun nanofibers based on an organoclay were used to design the first generation amperometric enzyme biosensor. PAMAM G2 dendrimers were used to intercalate montmorillonite clay (Mt) and then the modification of Mt by PAMAM was characterized using FTIR, XRD, TGA and zeta potential measurements. After that nanofibers were prepared by electrospinning Mt and PAMAM-Mt using poly(vinyl) alcohol (PVA) as an auxiliary polymer and the formed PVA/PAMAM-Mt electrospun nanofibers were proved by SEM, TEM and AFM techniques. Finally, pyranose oxidases (PyOx) were immobilized on a glassy carbon electrode surface, which was modified using the PVA/PAMAM-Mt electrospun nanofibers. Amperometric measurements were carried out using buffer solution at -0.7 V under stirring conditions. The linear response for glucose was from 0.005 mM to 0.25 mM using PVA/Mt/PyOx and PVA/PAMAM-Mt/PyOx biosensors. The limit of detection was 0.7 μM glucose with PVA/PAMAM-Mt/PyOx biosensor. To detect glucose in real sample, measurements were carried out using soft drink cola as a substrate instead of glucose.

Gas storage using fullerene based adsorbents

NASA Technical Reports Server (NTRS)

Mikhael, Michael G. (Inventor); Loutfy, Raouf O. (Inventor); Lu, Xiao-Chun (Inventor); Li, Weijiong (Inventor)

2000-01-01

This invention is directed to the synthesis of high bulk density high gas absorption capacity adsorbents for gas storage applications. Specifically, this invention is concerned with novel gas absorbents with high gravimetric and volumetric gas adsorption capacities which are made from fullerene-based materials. By pressing fullerene powder into pellet form using a conventional press, then polymerizing it by subjecting the fullerene to high temperature and high inert gas pressure, the resulting fullerene-based materials have high bulk densities and high gas adsorption capacities. By pre-chemical modification or post-polymerization activation processes, the gas adsorption capacities of the fullerene-based adsorbents can be further enhanced. These materials are suitable for low pressure gas storage applications, such as oxygen storage for home oxygen therapy uses or on-board vehicle natural gas storage. They are also suitable for storing gases and vapors such as hydrogen, nitrogen, carbon dioxide, and water vapor.

A plasma arc reactor for fullerene research

NASA Astrophysics Data System (ADS)

Anderson, T. T.; Dyer, P. L.; Dykes, J. W.; Klavins, P.; Anderson, P. E.; Liu, J. Z.; Shelton, R. N.

1994-12-01

A modified Krätschmer-Huffman reactor for the mass production of fullerenes is presented. Fullerene mass production is fundamental for the synthesis of higher and endohedral fullerenes. The reactor employs mechanisms for continuous graphite-rod feeding and in situ slag removal. Soot collects into a Soxhlet extraction thimble which serves as a fore-line vacuum pump filter, thereby easing fullerene separation from soot. Thermal gravimetric analysis (TGA) for yield determination is reported. This TGA method is faster and uses smaller samples than Soxhlet extraction methods which rely on aromatic solvents. Production of 10 g of soot per hour is readily achieved utilizing this reactor. Fullerene yields of 20% are attained routinely.

Hybrid self-healing matrix using core-shell nanofibers and capsuleless microdroplets.

PubMed

Lee, Min Wook; An, Seongpil; Lee, Changmin; Liou, Minho; Yarin, Alexander L; Yoon, Sam S

2014-07-09

In this work, we developed novel self-healing anticorrosive hierarchical coatings that consist of several components. Namely, as a skeleton we prepared a core-shell nanofiber mat electrospun from emulsions of cure material (dimethyl methylhydrogen siloxane) in a poly(acrylonitrile) (PAN) solution in dimethylformamide. In these nanofibers, cure is in the core, while PAN is in the shell. The skeleton deposited on a protected surface is encased in an epoxy-based matrix, which contains emulsified liquid droplets of dimethylvinyl-terminated dimethylsiloxane resin monomer. When such hierarchical coatings are damaged, cure is released from the nanofiber cores and the resin monomer, released from the damaged matrix, is polymerized in the presence of cure. This polymerization and solidification process takes about 1-2 days and eventually heals the damaged material when solid poly(dimethylsiloxane) resin is formed. The self-healing effect was demonstrated using an electrochemical analogue of the scanning vibrating electrode technique. Damaged samples were left for 2 days. After that, the electric current through a damaged coating was found to be negligibly small for the samples with self-healing properties. On the other hand, for the samples without self-healing properties, the electric current was significant.

Recent progresses in application of fullerenes in cosmetics.

PubMed

Lens, Marko

2011-08-01

Cosmetic industry is a fast growing industry with the continuous development of new active ingredients for skin care products. Fullerene C(60) and its derivates have been subject of intensive research in the last few years. Fullerenes display a wide range of different biological activities. Strong antioxidant capacities and effective quenching radical oxygen species (ROS) made fullerenes suitable active compounds in the formulation of skin care products. Published evidence on biological activities of fullerenes relevant for their application in cosmetics use and examples of published patents are presented. Recent trends in the use of fullerenes in topical formulations and patents are reviewed. Future investigations covering application of fullerenes in skin care are discussed.

Fullerenes in an impact crater on the LDEF spacecraft

NASA Technical Reports Server (NTRS)

Radicati di Brozolo, F.; Bunch, T. E.; Fleming, R. H.; Macklin, J.

1994-01-01

The fullerenes C60 and C70 have been found to occur naturally on Earth and have also been invoked to explain features in the absorption spectra of interstellar clouds. But no definitive spectroscopic evidence exists for fullerenes in space and attempts to find fullerenes in carbonaceous chondrites have been unsuccessful. Here we report the observation of fullerenes associated with carbonaceous impact residue in a crater on the Long Duration Exposure Facility (LDEF) spacecraft. Laser ionization mass spectrometry and Raman spectroscopy indicate the presence of fullerenes in the crater and in adjacent ejecta. Man-made fullerenes survive experimental hypervelocity (approximately 6.1 km s-1) impacts into aluminium targets, suggesting that space fullerenes contained in a carbonaceous micrometeorite could have survived the LDEF impact at velocities towards the lower end of the natural particle encounter range (<13 km s-1). We also demonstrate that the fullerenes were unlikely to have formed as instrumental artefacts, nor are they present as contaminants. Although we cannot specify the origin of the fullerenes with certainty, the most plausible source is the chondritic impactor. If, alternatively, the impact produced the fullerenes in situ on LDEF, then this suggests a viable mechanism for fullerene production in space.

Novel Nanofiber-based Membrane Separators for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Yanilmaz, Meltem

Lithium-ion batteries have been widely used in electronic devices including mobile phones, laptop computers, and cameras due to their high specific energy, high energy density, long cycling lifetime, and low self-discharge rate. Nowadays, lithium-ion batteries are finding new applications in electric/hybrid vehicles and energy storage for smart grids. To be used in these new applications, novel battery components are needed so that lithiumion batteries with higher cell performance, better safety, and lower cost can be developed. A separator is an important component to obtain safe batteries and its primary function is to prevent electronic contact between electrodes while regulating cell kinetics and ionic flow. Currently, microporous membranes are the most commonly used separator type and they have good mechanical properties and chemical stability. However, their wettability and thermal stabilities are not sufficient for applications that require high operating temperature and high performance. Due to the superior properties such as large specific surface area, small pore size and high porosity, electrospun nanofiber membranes can be good separator candidate for highperformance lithium-ion batteries. In this work, we focus our research on fabricating nanofiber-based membranes to design new high-performance separators with good thermal stability, as well as superior electrochemical performance compared to microporous polyolefin membranes. To combine the good mechanical strength of PP nonwovens with the excellent electrochemical properties of SiO2/polyvinylidene fluoride (PVDF) composite nanofibers, SiO 2/PVDF composite nanofiber-coated PP nonwoven membranes were prepared. It was found that the addition of SiO2 nanoparticles played an important role in improving the overall performance of these nanofiber-coated nonwoven membranes. Although ceramic/polymer composites can be prepared by encapsulating ceramic particles directly into polymer nanofibers, the performance

Anion-π Catalysis on Fullerenes.

PubMed

López-Andarias, Javier; Frontera, Antonio; Matile, Stefan

2017-09-27

Anion-π interactions on fullerenes are about as poorly explored as the use of fullerenes in catalysis. However, strong exchange-correlation contributions and the localized π holes on their surface promise unique selectivities. To elaborate on this promise, tertiary amines are attached nearby. Dependent on their positioning, the resulting stabilization of anionic transition states on fullerenes is shown to accelerate disfavored enolate addition and exo Diels-Alder reactions enantioselectively. The found selectivities are consistent with computational simulations, particularly concerning the discrimination of differently planarized and charge-delocalized enolate tautomers by anion-π interactions. Enolate-π interactions on fullerenes are much shorter than standard π-π interactions and anion-π interactions on planar surfaces, and alternative cation-π interactions are not observed. These findings open new perspectives with regard to anion-π interactions in general and the use of carbon allotropes in catalysis.

Vertically Aligned Carbon Nanofiber based Biosensor Platform for Glucose Sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al Mamun, Khandaker A.; Tulip, Fahmida S.; MacArthur, Kimberly

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, sensingmore » 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« less

Optical limiting of high-repetition-rate laser pulses by carbon nanofibers suspended in polydimethylsiloxane

NASA Astrophysics Data System (ADS)

Videnichev, Dmitry A.; Belousova, Inna M.

2014-06-01

The optical limiting (OL) behavior of carbon nanofibers (CNFs) in polydimethylsiloxane (PDMS) was studied and compared with that of CNFs in water, and polyhedral multi-shell fullerene-like nanostructures (PMFNs) also in water. It was shown that when switching from single-shot to pulse-periodic regime of laser pulses (10 Hz), the CNF in PDMS suspension retains its OL characteristics, while in the aqueous suspensions, considerable degradation of OL characteristics is observed. It was also observed that a powerful laser pulse causes the CNF in PDMS suspension to become opaque for at least three seconds, while such a pulse brings out a bleaching effect in aqueous PMFN and CNF suspensions. The processes of OL degradation in aqueous suspensions, bleaching and darkening of the studied materials are discussed herein.

Nanofiber quantum photonics

NASA Astrophysics Data System (ADS)

Nayak, Kali P.; Sadgrove, Mark; Yalla, Ramachandrarao; Le Kien, Fam; Hakuta, Kohzo

2018-07-01

Recent advances in the coherent control of single quanta of light, photons, is a topic of prime interest, and is discussed under the banner of quantum photonics. In the last decade, the subwavelength diameter waist of a tapered optical fiber, referred to as an optical nanofiber, has opened promising new avenues in the field of quantum optics, paving the way toward a versatile platform for quantum photonics applications. The key feature of the technique is that the optical field can be tightly confined in the transverse direction while propagating over long distances as a guided mode and enabling strong interaction with the surrounding medium in the evanescent region. This feature has led to surprising possibilities to manipulate single atoms and fiber-guided photons, e.g. the efficient channeling of emission from single atoms and solid-state quantum emitters into the fiber-guided modes, high optical depth with a few atoms around the nanofiber, trapping atoms around a nanofiber, and atomic memories for fiber-guided photons. Furthermore, implementing a moderate longitudinal confinement in nanofiber cavities has enabled the strong coupling regime of cavity quantum electrodynamics to be reached, and the long-range dipole–dipole interaction between quantum emitters mediated by the nanofiber offers a platform for quantum nonlinear optics with an ensemble of atoms. In addition, the presence of a longitudinal component of the guided field has led to unique capabilities for chiral light–matter interactions on nanofibers. In this article, we review the key developments of the nanofiber technology toward a vision for quantum photonics on an all-fiber interface.

Unique Crystallization of Fullerenes: Fullerene Flowers

PubMed Central

Kim, Jungah; Park, Chibeom; Song, Intek; Lee, Minkyung; Kim, Hyungki; Choi, Hee Cheul

2016-01-01

Solution-phase crystallization of fullerene molecules strongly depends on the types of solvent and their ratios because solvent molecules are easily included in the crystal lattice and distort its structure. The C70 (solute)–mesitylene (solvent) system yields crystals with various morphologies and structures, such as cubes, tubes, and imperfect rods. Herein, using C60 and C70 dissolved in mesitylene, we present a novel way to grow unique flower-shaped crystals with six symmetric petals. The different solubility of C60 and C70 in mesitylene promotes nucleation of C70 with sixfold symmetry in the early stage, which is followed by co-crystallization of both C60 and C70 molecules, leading to lateral petal growth. Based on the growth mechanism, we obtained more complex fullerene crystals, such as multi-deck flowers and tube-flower complexes, by changing the sequence and parameters of crystallization. PMID:27561446

Physical properties of organic fullerene cocrystals

NASA Astrophysics Data System (ADS)

Macovez, Roberto

2017-12-01

The basic facts and fundamental properties of binary fullerene cocrystals are reviewed, focusing especially on solvates and salts of Buckminsterfullerene (C60), and hydrates of hydrophilic C60 derivatives. The examined properties include the lattice structure and the presence of orientational disorder and/or rotational dynamics (of both fullerenes and cocrystallizing moieties), thermodynamic properties such as decomposition enthalpies, and charge transport properties. Both thermodynamic properties and molecular orientational disorder shed light on the extent of intermolecular interactions in these binary solid-state systems. Comparison is carried out also with pristine fullerite and with the solid phases of functionalized C60. Interesting experimental findings on binary fullerene cocrystals include the simultaneous occurrence of rotations of both constituent molecular species, crystal morphologies reminiscent of quasi-crystalline behaviour, the observation of proton conduction in hydrate solids of hydrophilic fullerene derivatives, and the production of super-hard carbon materials by application of high pressures on solvated fullerene crystals.

Uniform Li deposition regulated via three-dimensional polyvinyl alcohol nanofiber networks for effective Li metal anodes.

PubMed

Wang, Gang; Xiong, Xunhui; Lin, Zhihua; Zheng, Jie; Fenghua, Zheng; Li, Youpeng; Liu, Yanzhen; Yang, Chenghao; Tang, Yiwei; Liu, Meilin

2018-05-31

Lithium metal anodes are considered to be the most promising anode material for next-generation advanced energy storage devices due to their high reversible capacity and extremely low anode potential. Nevertheless, the formation of dendritic Li, induced by the repeated breaking and repairing of solid electrolyte interphase layers, always causes poor cycling performance and low coulombic efficiency, as well as serious safety problems, which have hindered the practical application of Li anodes for a long time. Herein, we design an electrode by covering a polyvinyl alcohol layer with a three-dimensional nanofiber network structure through an electrospinning technique. The polar functional groups on the surface of the polymer nanofibers can restrict the deposition of Li along the fibers and regulate the deposition of Li uniformly in the voids between the nanofibers. Owing to the structural features of the polymer, the modified Li|Cu electrode displays excellent cycle stability, with a high coulombic efficiency of 98.6% after 200 cycles at a current density of 1 mA cm-2 under a deposition capacity of 1 mA h cm-2, whilst the symmetric cell using the polymer modified Li anode shows stable cycling with a low hysteresis voltage of ∼80 mV over 600 h at a current density of 5 mA cm-2.

Site specific atomic polarizabilities in endohedral fullerenes and carbon onions

NASA Astrophysics Data System (ADS)

Zope, Rajendra R.; Bhusal, Shusil; Basurto, Luis; Baruah, Tunna; Jackson, Koblar

2015-08-01

We investigate the polarizability of trimetallic nitride endohedral fullerenes by partitioning the total polarizability into site specific components. This analysis indicates that the polarizability of the endohedral fullerene is essentially due to the outer fullerene cage and has insignificant contribution from the encapsulated unit. Thus, the outer fullerene cages effectively shield the encapsulated clusters and behave like Faraday cages. The polarizability of endohedral fullerenes is slightly smaller than the polarizability of the corresponding bare carbon fullerenes. The application of the site specific polarizabilities to C60@C240 and C60@C180 onions shows that, compared to the polarizability of isolated C60 fullerene, the encapsulation of the C60 in C240 and C180 fullerenes reduces its polarizability by 75% and 83%, respectively. The differences in the polarizability of C60 in the two onions is a result of differences in the bonding (intershell electron transfer), fullerene shell relaxations, and intershell separations. The site specific analysis further shows that the outer atoms in a fullerene shell contribute most to the fullerene polarizability.

Site specific atomic polarizabilities in endohedral fullerenes and carbon onions.

PubMed

Zope, Rajendra R; Bhusal, Shusil; Basurto, Luis; Baruah, Tunna; Jackson, Koblar

2015-08-28

We investigate the polarizability of trimetallic nitride endohedral fullerenes by partitioning the total polarizability into site specific components. This analysis indicates that the polarizability of the endohedral fullerene is essentially due to the outer fullerene cage and has insignificant contribution from the encapsulated unit. Thus, the outer fullerene cages effectively shield the encapsulated clusters and behave like Faraday cages. The polarizability of endohedral fullerenes is slightly smaller than the polarizability of the corresponding bare carbon fullerenes. The application of the site specific polarizabilities to C60@C240 and C60@C180 onions shows that, compared to the polarizability of isolated C60 fullerene, the encapsulation of the C60 in C240 and C180 fullerenes reduces its polarizability by 75% and 83%, respectively. The differences in the polarizability of C60 in the two onions is a result of differences in the bonding (intershell electron transfer), fullerene shell relaxations, and intershell separations. The site specific analysis further shows that the outer atoms in a fullerene shell contribute most to the fullerene polarizability.

Field-Effect Control of Graphene-Fullerene Thermoelectric Nanodevices.

PubMed

Gehring, Pascal; Harzheim, Achim; Spièce, Jean; Sheng, Yuewen; Rogers, Gregory; Evangeli, Charalambos; Mishra, Aadarsh; Robinson, Benjamin J; Porfyrakis, Kyriakos; Warner, Jamie H; Kolosov, Oleg V; Briggs, G Andrew D; Mol, Jan A

2017-11-08

Although it was demonstrated that discrete molecular levels determine the sign and magnitude of the thermoelectric effect in single-molecule junctions, full electrostatic control of these levels has not been achieved to date. Here, we show that graphene nanogaps combined with gold microheaters serve as a testbed for studying single-molecule thermoelectricity. Reduced screening of the gate electric field compared to conventional metal electrodes allows control of the position of the dominant transport orbital by hundreds of meV. We find that the power factor of graphene-fullerene junctions can be tuned over several orders of magnitude to a value close to the theoretical limit of an isolated Breit-Wigner resonance. Furthermore, our data suggest that the power factor of an isolated level is only given by the tunnel coupling to the leads and temperature. These results open up new avenues for exploring thermoelectricity and charge transport in individual molecules and highlight the importance of level alignment and coupling to the electrodes for optimum energy conversion in organic thermoelectric materials.

Highly branched RuO2 Nanorods on Electrospun TiO2 Nanofibers toward Electrochemical Catalysts

NASA Astrophysics Data System (ADS)

Cho, Yukyung; Kim, Su-Jin; Lee, Nam-Suk; Kim, Myung Hwa; Lee, Youngmi

2014-03-01

We report a facile growth route to synthesize hierarchically grown single crystalline metallic RuO2 nanorods on electrospun TiO2 nanofibers via a combination of a simple vapour phase transport process with an electrospinning process. This synthetic strategy could be very useful to design a variety of highly branched network architectures of the functional hetero-nanostructures for electrochemical applications. Particularly, Ruthenium oxide (RuO2) 1-dimensional nanostructures can be used as the effective catalysts or electrochemical electrode materials. Thus, we first synthesize TiO2 nanofibers from mixture of titanium isopropoxide precursor and polymer and then ruthenium hydroxide precursor on TiO2 nanofibers are transformed into RuO2 nanorods by thermal treatment at 250oC in air. The crystalline structures of products are confirmed using scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) spectrum, Raman spectroscopy, and high resolution electron microscopy (HRTEM). The fundamental electrochemical performances are examined using cyclic voltammetry (CV).

Porous block nanofiber composite filters

DOEpatents

Ginley, David S.; Curtis, Calvin J.; Miedaner, Alexander; Weiss, Alan J.; Paddock, Arnold

2016-08-09

Porous block nano-fiber composite (110), a filtration system (10) and methods of using the same are disclosed. An exemplary porous block nano-fiber composite (110) includes a porous block (100) having one or more pores (200). The porous block nano-fiber composite (110) also includes a plurality of inorganic nano-fibers (211) formed within at least one of the pores (200).

Non-fullerene electron acceptors for organic photovoltaic devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jenekhe, Samson A.; Li, Haiyan; Earmme, Taeshik

Non-fullerene electron acceptors for highly efficient organic photovoltaic devices are described. The non-fullerene electron acceptors have an extended, rigid, .pi.-conjugated electron-deficient framework that can facilitate exciton and charge derealization. The non-fullerene electron acceptors can physically mix with a donor polymer and facilitate improved electron transport. The non-fullerene electron acceptors can be incorporated into organic electronic devices, such as photovoltaic cells.

Polyaniline Nanofibers as the Hole Transport Medium in an Inverse Dye-Sensitized Solar Cell

NASA Astrophysics Data System (ADS)

Hesselsweet, Ian Brock

In order to become a viable alternative to silicon photovoltaics, dye-sensitized solar cells must overcome several issues primarily resulting from their use of a liquid electrolyte. Much research has gone into correcting these shortcomings by replacing the liquid electrolyte with solid-state hole-transport media. Using these solid-state materials brings new difficulties, such as completely filling the pores in the TiO2 nanostructure, and achieving good adhesion with the dye-coated TiO2. A novel approach to addressing these difficulties is the inverse dye-sensitized solar cell design. In this method the devices are constructed in reverse order, with the solidstate hole-transport medium providing the nanostructure instead of the TiO2. This allows new materials and methods to be used which may better address these issues. In this project, inverse dye-sensitized solar cells using polyaniline nanofibers as the hole transport medium were prepared and characterized. The devices were prepared on fluorine-doped tin oxide (FTO) coated glass electrodes. The first component was a dense spin-coated polyaniline blocking layer, to help prevent short circuiting of the devices. The second layer was a thin film of drop cast polyaniline nanofibers which acted as the hole transport medium and provided high surface area for the dye attachment. The dye used was 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP), which was covalently attached to the nanofibers using a Friedel-Crafts acylation. Titania gel was then deposited into the pores of the nanofiber film by controlled hydrolysis of a titanium complex (Tyzor LA). A back electrode of TiO2 nanoparticles sintered on FTO was pressed on top to complete the devices. A typical device generated an open circuit voltage of 0.17 V and a closed circuit current of 5.7 nA/cm2 while the highest open circuit voltage recorded for any variation on a device was 0.31 V and the highest short circuit current was 52 nA/cm2 under AM 1.5 simulated solar

Hierarchically mesostructured porous TiO2 hollow nanofibers for high performance glucose biosensing.

PubMed

Guo, Qiaohui; Liu, Lijuan; Zhang, Man; Hou, Haoqing; Song, Yonghai; Wang, Huadong; Zhong, Baoying; Wang, Li

2017-06-15

Effective immobilization of enzymes on an electrode surface is of great importance for biosensor development, but it still remains challenging because enzymes tend to denaturation and/or form close-packed structures. In this work, a free-standing TiO 2 hollow nanofibers (HNF-TiO 2 ) was successfully prepared by a simple and scalable electrospun nanofiber film template-assisted sol-gel method, and was further explored for glucose oxidase (GOD) immobilization and biosensing. This porous and nanotubular HNF-TiO 2 provides a well-defined hierarchical nanostructure for GOD loading, and the fine TiO 2 nanocrystals facilitate direct electron transfer from GOD to the electrode, also the strong interaction between GOD and HNF-TiO 2 greatly enhances the stability of the biosensor. The as-prepared glucose biosensors show good sensing performances both in O 2 -free and O 2 -containing conditions with good sensitivity, satisfactory selectivity, long-term stability and sound reliability. The novel textile formation, porous and hierarchically mesostructured nature of HNF-TiO 2 with excellent analytical performances make it a superior platform for the construction of high-performance glucose biosensors. Copyright © 2016 Elsevier B.V. All rights reserved.

Transmutation of fullerenes.

PubMed

Cross, R James; Saunders, Martin

2005-03-09

Fullerenes were pyrolyzed by subliming them into a stream of flowing argon gas and then passing them through an oven heated to approximately 1000 degrees C. C(76), C(78), and C(84) all readily lost carbons to form smaller fullerenes. In the case of C(78), some isomerization was seen. Pyrolysis of (3)He@C(76) showed that all or most of the (3)He was lost during the decomposition. C(60) passes through the apparatus with no decomposition and no loss of helium.

Fullerene derivatives as electron donor for organic photovoltaic cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhuang, Taojun; Wang, Xiao-Feng, E-mail: xf-wang@yz.yamagata-u.ac.jp, E-mail: ziruo@yz.yamagata-u.ac.jp; Sano, Takeshi

2013-11-11

We demonstrated the performance of unconventional, all-fullerene-based, planar heterojunction (PHJ) organic photovoltaic (OPV) cells using fullerene derivatives indene-C{sub 60} bisadduct (ICBA) and phenyl C{sub 61}-butyric acid methyl ester as the electron donors with fullerene C{sub 70} as the electron acceptor. Two different charge generation processes, including charge generation in the fullerene bulk and exciton dissociation at the donor-acceptor interface, have been found to exist in such all-fullerene-based PHJ cells and the contribution to the total photocurrent from each process is strongly dependent on the thickness of fullerene donor. The optimized 5 nm ICBA/40 nm C{sub 70} PHJ cell gives clear external quantummore » efficiency responses for the long-wavelength photons corresponding to the dissociation of strongly bound Frenkel excitons, which is hardly observed in fullerene-based single layer reference devices. This approach using fullerene as a donor material provides further possibilities for developing high performance OPV cells.« less

Catalytic, conductive, and transparent platinum nanofiber webs for FTO-free dye-sensitized solar cells.

PubMed

Kim, Jongwook; Kang, Jonghyun; Jeong, Uiyoung; Kim, Heesuk; Lee, Hyunjung

2013-04-24

We report a multifunctional platinium nanofiber (PtNF) web that can act as a catalyst layer in dye-sensitized solar cell (DSSC) to simultaneously function as a transparent counter electrode (CE), i.e., without the presence of an indium-doped tin oxide (ITO) or fluorine-doped tin oxide (FTO) glass. This PtNF web can be easily produced by electrospinning, which is highly cost-effective and suitable for large-area industrial-scale production. Electrospun PtNFs are straight and have a length of a few micrometers, with a common diameter of 40-70 nm. Each nanofiber is composed of compact, crystalline Pt grains and they are well-fused and highly interconnected, which should be helpful to provide an efficient conductive network for free electron transport and a large surface area for electrocatalytic behavior. A PtNF web is served as a counter electrode in DSSC and the photovoltaic performance increases up to a power efficiency of 6.0%. It reaches up to 83% of that in a conventional DSSC using a Pt-coated FTO glass as a counter electrode. Newly designed DSSCs containing PtNF webs display highly stable photoelectric conversion efficiencies, and excellent catalytic, conductive, and transparent properties, as well as long-term stability. Also, while the DSSC function is retained, the fabrication cost is reduced by eliminating the transparent conducting layer on the counter electrode. The presented method of fabricating DSSCs based on a PtNF web can be extended to other electrocatalytic optoelectronic devices that combine superior catalytic activity with high conductivity and transparency.

Site specific atomic polarizabilities in endohedral fullerenes and carbon onions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zope, Rajendra R., E-mail: rzope@utep.edu; Baruah, Tunna; Computational Science Program, The University of Texas at El Paso, El Paso, Texas 79958

2015-08-28

We investigate the polarizability of trimetallic nitride endohedral fullerenes by partitioning the total polarizability into site specific components. This analysis indicates that the polarizability of the endohedral fullerene is essentially due to the outer fullerene cage and has insignificant contribution from the encapsulated unit. Thus, the outer fullerene cages effectively shield the encapsulated clusters and behave like Faraday cages. The polarizability of endohedral fullerenes is slightly smaller than the polarizability of the corresponding bare carbon fullerenes. The application of the site specific polarizabilities to C{sub 60}@C{sub 240} and C{sub 60}@C{sub 180} onions shows that, compared to the polarizability of isolatedmore » C{sub 60} fullerene, the encapsulation of the C{sub 60} in C{sub 240} and C{sub 180} fullerenes reduces its polarizability by 75% and 83%, respectively. The differences in the polarizability of C{sub 60} in the two onions is a result of differences in the bonding (intershell electron transfer), fullerene shell relaxations, and intershell separations. The site specific analysis further shows that the outer atoms in a fullerene shell contribute most to the fullerene polarizability.« less

Cobalt Oxide Porous Nanofibers Directly Grown on Conductive Substrate as a Binder/Additive-Free Lithium-Ion Battery Anode with High Capacity.

PubMed

Liu, Hao; Zheng, Zheng; Chen, Bochao; Liao, Libing; Wang, Xina

2017-12-01

In order to reduce the amount of inactive materials, such as binders and carbon additives in battery electrode, porous cobalt monoxide nanofibers were directly grown on conductive substrate as a binder/additive-free lithium-ion battery anode. This electrode exhibited very high specific discharging/charging capacities at various rates and good cycling stability. It was promising as high capacity anode materials for lithium-ion battery.

A novel H(2)O(2) amperometric biosensor based on gold nanoparticles/self-doped polyaniline nanofibers.

PubMed

Chen, Xiaojun; Chen, Zixuan; Zhu, Jinwei; Xu, Chenbin; Yan, Wei; Yao, Cheng

2011-10-01

A new kind of gold nanoparticles/self-doped polyaniline nanofibers (Au/SPAN) with grooves has been prepared for the immobilization of horseradish peroxidase (HRP) on the surface of glassy carbon electrode (GCE). The ratio of gold in the composite nanofibers was up to 64%, which could promote the conductivity and biocompatibility of SPAN and increase the immobilized amount of HRP molecules greatly. The electrode exhibits enhanced electrocatalytic activity in the reduction of H(2)O(2) in the presence of the mediator hydroquinone (HQ). The effects of concentration of HQ, solution pH and the working potential on the current response of the modified electrode toward H(2)O(2) were optimized to obtain the maximal sensitivity. The proposed biosensor exhibited a good linear response in the range from 10 to 2000 μM with a detection limit of 1.6 μM (S/N=3) under the optimum conditions. The response showed Michaelis-Menten behavior at larger H(2)O(2) concentrations, and the apparent Michaelis-Menten constant K(m) was estimated to be 2.21 mM. The detection of H(2)O(2) concentration in real sample showed acceptable accuracy with the traditional potassium permanganate titration. Copyright © 2011 Elsevier B.V. All rights reserved.

Fabrication of nanofibers reinforced polymer microstructures using femtosecond laser material processing

NASA Astrophysics Data System (ADS)

Alubaidy, Mohammed-Amin

A new method has been introduced for the formation of microfeatures made of nanofibers reinforced polymer, using femtosecond laser material processing. The Femtosecond laser is used for the generation of three-dimensional interweaved nanofibers and the construction of microfeatures, like microchannels and voxels, through multi photon polymerization of nanofiber dispersed polymer resin. A new phenomenon of multiphoton polymerization induced by dual wavelength irradiation was reported for the first time. A significant improvement in the spatial resolution, compared to the two photon absorption (2PA) and the three photon absorption (3PA) processes has been achieved. Conductive polymer microstructures and magnetic polymer microstructures have been fabricated through this method. The mechanical properties of nanofiber reinforced polymer microstructures has been investigated by means of nanoindentation and the volume fraction of the generated nanofibers in the nanocomposite was calculated by using nanoindentation analysis. The results showed significant improvement in strength of the material. The electrical conductivity of the two photon polymerization (TPP) generated microfeatures was measured by a two-probe system at room temperature and the conductivity-temperature relationship was measured at a certain temperature range. The results suggest that the conductive polymer microstructure is reproducible and has a consistent conductivity-temperature relation. The magnetic strength has been characterized using Guassmeter. To demonstrate the potential application of the new fabrication method, a novel class of DNA-functionalized three-dimensional (3D), stand-free, and nanostructured electrodes were fabricated. The developed nanofibrous DNA biosensor has been characterized by cyclic voltammetry with the use of ferrocyanide as an electrochemical redox indicator. Results showed that the probe--target recognition has been improved. This research demonstrated that femtosecond

Electrospinning of nanofibers from non-polymeric systems: polymer-free nanofibers from cyclodextrin derivatives

NASA Astrophysics Data System (ADS)

Celebioglu, Asli; Uyar, Tamer

2012-01-01

High molecular weight polymers and high polymer concentrations are desirable for the electrospinning of nanofibers since polymer chain entanglements and overlapping are important for uniform fiber formation. Hence, the electrospinning of nanofibers from non-polymeric systems such as cyclodextrins (CDs) is quite a challenge since CDs are cyclic oligosaccharides. Nevertheless, in this study, we have successfully achieved the electrospinning of nanofibers from chemically modified CDs without using a carrier polymer matrix. Polymer-free nanofibers were electrospun from three different CD derivatives, hydroxypropyl-β-cyclodextrin (HPβCD), hydroxypropyl-γ-cyclodextrin (HPγCD) and methyl-β-cyclodextrin (MβCD) in three different solvent systems, water, dimethylformamide (DMF) and dimethylacetamide (DMAc). We observed that the electrospinning of these CDs is quite similar to polymeric systems in which the solvent type, the solution concentration and the solution conductivity are some of the key factors for obtaining uniform nanofibers. Dynamic light scattering (DLS) measurements indicated that the presence of considerable CD aggregates and the very high solution viscosity were playing a key role for attaining nanofibers from CD derivatives without the use of any polymeric carrier. The electrospinning of CD solutions containing urea yielded no fibers but only beads or splashes since urea caused a notable destruction of the self-associated CD aggregates in their concentrated solutions. The structural, thermal and mechanical characteristics of the CD nanofibers were also investigated. Although the CD derivatives are amorphous small molecules, interestingly, we observed that these electrospun CD nanofibers/nanowebs have shown some mechanical integrity by which they can be easily handled and folded as a free standing material.

Edge-Oriented Graphene on Carbon Nanofiber for High-Frequency Supercapacitors

NASA Astrophysics Data System (ADS)

Islam, Nazifah; Warzywoda, Juliusz; Fan, Zhaoyang

2018-03-01

High-frequency supercapacitors are being studied with the aim to replace the bulky electrolytic capacitors for current ripple filtering and other functions used in power systems. Here, 3D edge-oriented graphene (EOG) was grown encircling carbon nanofiber (CNF) framework to form a highly conductive electrode with a large surface area. Such EOG/CNF electrodes were tested in aqueous and organic electrolytes for high-frequency supercapacitor development. For the aqueous and the organic cell, the characteristic frequency at - 45° phase angle was found to be as high as 22 and 8.5 kHz, respectively. At 120 Hz, the electrode capacitance density was 0.37 and 0.16 mF cm-2 for the two cells. In particular, the 3 V high-frequency organic cell was successfully tested as filtering capacitor used in AC/DC converter, suggesting the promising potential of this technology for compact power supply design and other applications. [Figure not available: see fulltext.

The first true inorganic fullerenes?

NASA Astrophysics Data System (ADS)

Parilla, P. A.; Dillon, A. C.; Jones, K. M.; Riker, G.; Schulz, D. L.; Ginley, D. S.; Heben, M. J.

1999-01-01

Boron nitride and materials of composition MX2, where M is molybdenum or tungsten and X is sulphur or selenium, can form fullerene-like structures such as nested polyhedra or nanotubes. However, the analogy to the carbon fullerene family falls short because no small preferred structure akin to C60(ref. 5) has been found. We have discovered nano-octahedra of MoS2of discrete sizes in soots that we prepared by laser ablation of pressed MoS2targets. These nano-octahedra are much larger than C60structures, having edge lengths of about 4.0 and 5.0 nanometres, and may represent the first `inorganic fullerenes'.

Motion of Fullerenes around Topological Defects on Metals: Implications for the Progress of Molecular Scale Devices.

PubMed

Nirmalraj, Peter; Daly, Ronan; Martin, Nazario; Thompson, Damien

2017-03-08

Research on motion of molecules in the presence of thermal noise is central for progress in two-terminal molecular scale electronic devices. However, it is still unclear what influence imperfections in bottom metal electrode surface can have on molecular motion. Here, we report a two-layer crowding study, detailing the early stages of surface motion of fullerene molecules on Au(111) with nanoscale pores in a n-tetradecane chemical environment. The motion of the fullerenes is directed by crowding of the underlying n-tetradecane molecules around the pore fringes at the liquid-solid interface. We observe in real-space the growth of molecular populations around different pore geometries. Supported by atomic-scale modeling, our findings extend the established picture of molecular crowding by revealing that trapped solvent molecules serve as prime nucleation sites at nanopore fringes.

Oriented nanofibers embedded in a polymer matrix

NASA Technical Reports Server (NTRS)

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.

Memory operation mechanism of fullerene-containing polymer memory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakajima, Anri, E-mail: anakajima@hiroshima-u.ac.jp; Fujii, Daiki

2015-03-09

The memory operation mechanism in fullerene-containing nanocomposite gate insulators was investigated while varying the kind of fullerene in a polymer gate insulator. It was cleared what kind of traps and which positions in the nanocomposite the injected electrons or holes are stored in. The reason for the difference in the easiness of programming was clarified taking the role of the charging energy of an injected electron into account. The dependence of the carrier dynamics on the kind of fullerene molecule was investigated. A nonuniform distribution of injected carriers occurred after application of a large magnitude programming voltage due to themore » width distribution of the polystyrene barrier between adjacent fullerene molecules. Through the investigations, we demonstrated a nanocomposite gate with fullerene molecules having excellent retention characteristics and a programming capability. This will lead to the realization of practical organic memories with fullerene-containing polymer nanocomposites.« less

PREFACE: Fullerene Nano Materials (Symposium of IUMRS-ICA2008)

NASA Astrophysics Data System (ADS)

Miyazawa, Kun'ichi; Fujita, Daisuke; Wakahara, Takatsugu; Kizuka, Tokushi; Matsuishi, Kiyoto; Ochiai, Yuichi; Tachibana, Masaru; Ogata, Hironori; Mashino, Tadahiko; Kumashiro, Ryotaro; Oikawa, Hidetoshi

2009-07-01

This volume contains peer-reviewed invited and contributed papers that were presented in Symposium N 'Fullerene Nano Materials' at the IUMRS International Conference in Asia 2008 (IUMRS-ICA 2008), which was held on 9-13 December 2008, at Nagoya Congress Center, Nagoya, Japan. Over twenty years have passed since the discovery of C60 in 1985. The discovery of superconductivity of C60 in 1991 suggested infinite possibilities for fullerenes. On the other hand, a new field of nanocarbon has been developed recently, based on novel functions of the low-dimensional fullerene nanomaterials that include fullerene nanowhiskers, fullerene nanotubes, fullerene nanosheets, chemically modified fullerenes, endohedral fullerenes, thin films of fullerenes and so forth. Electrical, electrochemical, optical, thermal, mechanical and various other properties of fullerene nanomaterials have been investigated and their novel and anomalous nature has been reported. Biological properties of fullerene nanomaterials also have been investigated both in medical applications and toxicity aspects. The recent research developments of fullerene nanomaterials cover a variety of categories owing to their functional diversity. This symposium aimed to review the progress in the state-of-the-art technology based on fullerenes and to offer the forum for active interdisciplinary discussions. 24 oral papers containing 8 invited papers and 22 poster papers were presented at the two-day symposium. Topics on the social acceptance of nanomaterials including fullerene were presented on the first day of the symposium. Biological impacts of nanomaterials and the importance of standardization of nanomaterials characterization were also shown. On the second day, the synthesis, properties, functions and applications of various fullerene nanomaterials were shown in both the oral and poster presentations. We are grateful to all invited speakers and many participants for valuable contributions and active discussions

Investigations on silver/polyaniline electrodes for electrochemical supercapacitors.

PubMed

Patil, Dipali S; Shaikh, J S; Pawar, S A; Devan, R S; Ma, Y R; Moholkar, A V; Kim, J H; Kalubarme, R S; Park, C J; Patil, P S

2012-09-14

Polyaniline (PANI) and silver doped polyaniline (Ag/PANI) thin films were deposited on stainless steel substrates by a dip coating technique. To study the effect of doping concentration of Ag on the specific capacitance of PANI the concentration of Ag was varied from 0.3 to 1.2 weight percent. Fourier transform-infrared and Fourier transform-Raman spectroscopy, and energy dispersion X-ray techniques were used for the phase identification and determination of the doping content in the PANI films, respectively. The surface morphology of the films was examined by Field Emission Scanning Electron Microscopy, which revealed a nanofiber like structure for PANI and nanofibers with bright spots of Ag particles for the Ag/PANI films. There was decrease in the room temperature electrical resistivity of the Ag/PANI films of the order of 10(2) with increasing Ag concentration. The supercapacitive behavior of the electrodes was tested in a three electrode system using 1.0 M H(2)SO(4) electrolyte. The specific capacitance increased from 285 F g(-1) (for PANI) to 512 F g(-1) for Ag/PANI at 0.9 weight percent doping of Ag, owing to the synergic effect of PANI and silver nanoparticles. This work demonstrates a simple strategy of improving the specific capacitance of polymer electrodes and may also be easily adopted for other dopants.

Asymmetric supercapacitors based on electrospun carbon nanofiber/sodium-pre-intercalated manganese oxide electrodes with high power and energy densities

NASA Astrophysics Data System (ADS)

Lin, Sheng-Chi; Lu, Yi-Ting; Chien, Yu-An; Wang, Jeng-An; Chen, Po-Yu; Ma, Chen-Chi M.; Hu, Chi-Chang

2018-07-01

The sodium-pre-intercalated δ-MnO2 is in-situ grown on carbon nanofiber via a simple, one-step method for the application of asymmetric supercapacitors. The pre-intercalation of Na ions into the layered structure of δ-MnO2 reduces the crystallinity, beneficial to Na+ diffusion into/out the interlayer structure and pseudocapacitive utilization of MnO2. This NaxMnO2@CNF nanocomposite with desirable pseudo-capacitance from δ-NaxMnO2 and high electric conductivity from CNF network shows a high specific capacitance of 321 F g-1 at 1 A g-1 with ca. 75.2% capacitance retention from 1 to 32 A g-1. An ASC cell consisting of this nanocomposite and activated carbon as the positive and negative electrodes can be reversibly charged and discharged to a cell voltage of 2.0 V in 1 M Na2SO4 and 4 mM NaHCO3 with specific energy and power of 21 Wh kg-1 and 1 kW kg-1, respectively. This ASC also shows excellent cell capacitance retention (7% decay) in the 2 V, 10,000-cycle stability test, revealing superior performance.

Planar silver nanowire, carbon nanotube and PEDOT:PSS nanocomposite transparent electrodes

NASA Astrophysics Data System (ADS)

Stapleton, Andrew J.; Yambem, Soniya D.; Johns, Ashley H.; Afre, Rakesh A.; Ellis, Amanda V.; Shapter, Joe G.; Andersson, Gunther G.; Quinton, Jamie S.; Burn, Paul L.; Meredith, Paul; Lewis, David A.

2015-04-01

Highly conductive, transparent and flexible planar electrodes were fabricated using interwoven silver nanowires and single-walled carbon nanotubes (AgNW:SWCNT) in a PEDOT:PSS matrix via an epoxy transfer method from a silicon template. The planar electrodes achieved a sheet resistance of 6.6 ± 0.0 Ω/□ and an average transmission of 86% between 400 and 800 nm. A high figure of merit of 367 Ω-1 is reported for the electrodes, which is much higher than that measured for indium tin oxide and reported for other AgNW composites. The AgNW:SWCNT:PEDOT:PSS electrode was used to fabricate low temperature (annealing free) devices demonstrating their potential to function with a range of organic semiconducting polymer:fullerene bulk heterojunction blend systems.

Ultrasonic dyeing of cellulose nanofibers.

PubMed

Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo

2016-07-01

Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing. Copyright © 2016 Elsevier B.V. All rights reserved.

Carboxylated Fullerene at the Oil/Water Interface.

PubMed

Li, Rongqiang; Chai, Yu; Jiang, Yufeng; Ashby, Paul D; Toor, Anju; Russell, Thomas P

2017-10-04

The self-assembly of carboxylated fullerene with poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) with different molecular weights, poly-2-vinylpyridine, and amine-terminated polystyrene, at the interface between toluene and water was investigated. For all values of the pH, the functionalized fullerene interacted with the polymers at the water/toluene interface, forming a nanoparticle network, reducing the interfacial tension. At pH values of 4.84 and 7.8, robust, elastic films were formed at the interface, such that hollow tubules could be formed in situ when an aqueous solution of the functionalized fullerene was jetted into a toluene solution of PS-b-P2VP at a pH of 4.84. With variation of the pH, the mechanical properties of the fullerene/polymer assemblies can be varied by tuning the strength of the interactions between the functionalized fullerenes and the PS-b-P2VP.

Method of manufacturing tin-doped indium oxide nanofibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ozcan, Soydan; Naskar, Amit K

2017-06-06

A method of making indium tin oxide nanofibers includes the step of mixing indium and tin precursor compounds with a binder polymer to form a nanofiber precursor composition. The nanofiber precursor composition is co-formed with a supporting polymer to form a composite nanofiber having a precursor composition nanofiber completely surrounded by the supporting polymer composition. The supporting polymer composition is removed from the composite nanofiber to expose the precursor composition nanofiber. The precursor composition nanofiber is then heated in the presence of oxygen such as O.sub.2 to form indium tin oxide and to remove the binder polymer to form anmore » indium tin oxide nanofiber. A method of making metal oxide nanofibers is also disclosed.« less

Is the interaction between Ti atoms and fullerenes the origin of the 21-μ m feature?

NASA Astrophysics Data System (ADS)

Kimura, Y.; Nuth, J. A., III; Ferguson, F. T.

2005-12-01

A 21-μ m-emission feature has been observed in the shells of carbon-rich post-asymptotic giant branch (AGB) stars. The carrier of the 21-μ m feature remains unidentified, although many candidate materials have been proposed, including nanodiamond, SiS2, a derivative of SiC and nanometer-sized TiC. In particular, TiC grains were extensively discussed after the report by von Helden (2000). Gas-phase TiC clusters less than 1 nm in diameter have been suggested as the source of the 21-μ m dust feature. The spectrum of TiC clusters recorded in the laboratory provides a good fit with the observational data. However, only negative results have been reported for both theoretical and laboratory experimental studies concerning TiC since the discovery by von Helden. Recent measurements of fullerenes and Ti atoms recorded in our laboratory have demonstrated the presence of an infrared feature near 21 μ m. The feature observed has nearly the same shape and position as is observed for one of the most enigmatic features in post-AGB stars. In our experimental system, large-cage carbon particles, such as large fullerenes, were produced from CO gas by the Boudouard reaction. Large-cage carbon particles intermixed with Ti atoms were produced by the evaporation of a Ti-metal-wrapped carbon electrode in CO gas. The infrared spectra of large fullerenes interacting with Ti atoms show a characteristic feature at 20.3 μ m that closely corresponds to the 20.1-μ m feature observed in post-AGB stars. Both the laboratory and stellar spectra also show a small but significant peak at 19.0 μ m, which is attributed to fullerenes. We propose that the interaction between fullerenes and Ti atoms may be a plausible explanation for the 21-μ m feature seen in some post-AGB stars.

Constructing I[subscript h] Symmetrical Fullerenes from Pentagons

ERIC Educational Resources Information Center

Gan, Li-Hua

2008-01-01

Twelve pentagons are sufficient and necessary to form a fullerene cage. According to this structural feature of fullerenes, we propose a simple and efficient method for the construction of I[subscript h] symmetrical fullerenes from pentagons. This method does not require complicated mathematical knowledge; yet it provides an excellent paradigm for…

Aligned Layers of Silver Nano-Fibers.

PubMed

Golovin, Andrii B; Stromer, Jeremy; Kreminska, Liubov

2012-02-01

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.

Synthesis of Continuous Conductive PEDOT:PSS Nanofibers by Electrospinning: A Conformal Coating for Optoelectronics.

PubMed

Bessaire, Bastien; Mathieu, Maillard; Salles, Vincent; Yeghoyan, Taguhi; Celle, Caroline; Simonato, Jean-Pierre; Brioude, Arnaud

2017-01-11

A process to synthesize continuous conducting nanofibers were developed using PEDOT:PSS as a conducting polymer and an electrospinning method. Experimental parameters were carefully explored to achieve reproducible conductive nanofibers synthesis in large quantities. In particular, relative humidity during the electrospinning process was proven to be of critical importance, as well as doping post-treatment involving glycols and alcohols. The synthesized fibers were assembled as a mat on glass substrates, forming a conductive and transparent electrode and their optoelectronic have been fully characterized. This method produces a conformable conductive and transparent coating that is well-adapted to nonplanar surfaces, having very large aspect ratio features. A demonstration of this property was made using surfaces having deep trenches and high steps, where conventional transparent conductive materials fail because of a lack of conformability.

Synergetic interface between NiO/Ni3S2 nanosheets and carbon nanofiber as binder-free anode for highly reversible lithium storage

NASA Astrophysics Data System (ADS)

Jiang, Jialin; Ma, Chao; Yang, Yinbo; Ding, Jingjing; Ji, Hongmei; Shi, Shaojun; Yang, Gang

2018-05-01

A novel heterostructure of NiO/Ni3S2 nanoflake is synthesized and composited with carbon nanofibers (CNF) membrane. NiO/Ni3S2 nanoflakes are homogeneously dispersed in CNF network, herein, NiO/Ni3S2 like leaf and CNF like branch. Carbon nanofibers network efficiently prevents the pulverization and buffers the volume changes of NiO/Ni3S2, meanwhile, NiO/Ni3S2 nanoflakes through the conductive channels of carbon nanofibers own improved Li+ diffusion ability and structural stability. The capacity of NiO/Ni3S2/CNF reaches to 519.2 mA g-1 after 200 cycles at the current density of 0.5 A g-1 while NiO/Ni3S2 fades to 71 mAh g-1 after 40 cycles. Owing to the synergetic structure, the resultant binder-free electrode NiO/Ni3S2/carbon nanofibers shows an excellent reversible lithium storage capability.

Linear response formulism of a carbon nano-onion stringed to gold electrodes

NASA Astrophysics Data System (ADS)

Kaur, Milanpreet; Sawhney, Ravinder Singh; Engles, Derick

2017-04-01

Density functional theory is used to investigate the electronic state of a carbon nano-onion conglobated by endohedral-ing the highly curved C20 fullerene within its parent fullerene C60. The Non-Equilibrium Green's Function is later employed to examine the quantum transport when the carbon nano-onion, C20@C60 is stringed to the pair of gold electrodes of (001) plane. The computed results are evaluated and compared with C20 and C60 junctions. The calculated electronic parameters of these molecular junctions are utilized to extrapolate their two electrical parameters: current and conductance. The carbon nano-onion junction assembled from the C20 and C60 molecules displays the combined effect of their molecular junctions when organized separately. Also, the insertion of C20 molecule in the hollow cavity of C60 fullerene leads to the enhancement of its current and conductance in carbon nano-onion junction formed, when compared to the one constructed otherwise.

Process for the removal of impurities from combustion fullerenes

DOEpatents

Alford, J. Michael; Bolskar, Robert

2005-08-02

The invention generally relates to purification of carbon nanomaterials, particularly fullerenes, by removal of PAHs and other hydrocarbon impurities. The inventive process involves extracting a sample containing carbon nanomaterials with a solvent in which the PAHs are substantially soluble but in which the carbon nanomaterials are not substantially soluble. The sample can be repeatedly or continuously extracted with one or more solvents to remove a greater amount of impurities. Preferred solvents include ethanol, diethyl ether, and acetone. The invention also provides a process for efficiently separating solvent extractable fullerenes from samples containing fullerenes and PAHs wherein the sample is extracted with a solvent in which both fullerenes and PAHs are substantially soluble and the sample extract then undergoes selective extraction to remove PAHs. Suitable solvents in which both fullerenes and PAHs are soluble include o-xylene, toluene, and o-dichlorobenzene. The purification process is capable of treating quantities of combustion soot in excess of one kilogram and can produce fullerenes or fullerenic soot of suitable purity for many applications.

Electrospun nanofibers for neural tissue engineering

NASA Astrophysics Data System (ADS)

Xie, Jingwei; MacEwan, Matthew R.; Schwartz, Andrea G.; Xia, Younan

2010-01-01

Biodegradable nanofibers produced by electrospinning represent a new class of promising scaffolds to support nerve regeneration. We begin with a brief discussion on the electrospinning of nanofibers and methods for controlling the structure, porosity, and alignment of the electrospun nanofibers. The methods include control of the nanoscale morphology and microscale alignment of the nanofibers, as well as the fabrication of macroscale, three-dimensional tubular structures. We then highlight recent studies that utilize electrospun nanofibers to manipulate biological processes relevant to nervous tissue regeneration, including stem cell differentiation, guidance of neurite extension, and peripheral nerve injury treatments. The main objective of this feature article is to provide valuable insights into methods for investigating the mechanisms of neurite growth on novel nanofibrous scaffolds and optimization of the nanofiber scaffolds and conduits for repairing peripheral nerve injuries.

Harnessing Structure-Property Relationships for Poly(alkyl thiophene)-Fullerene Derivative Thin Filmsto Optimize Performance in Photovoltaic Devices

DOE PAGES

Deb, Nabankur; Li, Bohao; Skoda, Maximilian; ...

2016-02-08

Nanoscale bulk heterojunction (BHJ) systems, consisting of fullerenes dispersed in conjugated polymers as the active component, have been actively studied over the last decades in order to produce high performance organic photovoltaics (OPVs). A significant role in device efficiency is played by the active layer morphology, but despite considerable study, a full understanding of the exact role that morphology plays and therefore a definitive method to produce and control an ideal morphology is lacking. In order to understand the BHJ phase behavior and associated morphology in these devices, we have used neutron reflection, together with grazing incidence X-ray and neutronmore » scattering and X-ray photoelectron spectroscopy (XPS) to determine the morphology of the BHJ active layer in functional devices. We have studied nine model BHJ systems based on mixtures of three poly(3-alkyl thiophenes, P3AT) (A=butyl, hexyl, octyl) blended with three different fullerene derivatives, which provides variations in crystallinity and miscibility within the BHJ composite. In studying properties of functional devices, we show a direct correlation between the observed morphology within the BHJ layer and the device performance metrics, i.e., the short-circuit current (J SC), fill factor (FF), open-circuit voltage (VOC) and overall power conversion efficiency (PCE). Using these model systems, the effect of typical thermal annealing processes on the BHJ morphology through the film thickness as a function of the polythiophene-fullerene mixtures and different electron transport layer interfaces has been determined. It is shown that fullerene enrichment occurs at both the electrode interfaces after annealing. The degree of fullerene enrichment is found to strongly correlate with J SC and to a lesser degree with FF. Finally, based on these findings we demonstrate that by deliberately adding a fullerene layer at the electron transport layer interface, J SC can be increased by up to 20

N-doped amorphous carbon coated Fe3O4/SnO2 coaxial nanofibers as a binder-free self-supported electrode for lithium ion batteries.

PubMed

Xie, Wenhe; Li, Suyuan; Wang, Suiyan; Xue, Song; Liu, Zhengjiao; Jiang, Xinyu; He, Deyan

2014-11-26

N-doped amorphous carbon coated Fe3O4/SnO2 coaxial nanofibers were prepared via a facile approach. The core composite nanofibers were first made by electrospinning technology, then the shells were conformally coated using the chemical bath deposition and subsequent carbonization with polydopamine as a carbon source. When applied as a binder-free self-supported anode for lithium ion batteries, the coaxial nanofibers displayed an enhanced electrochemical storage capacity and excellent rate performance. The morphology of the interwoven nanofibers was maintained even after the rate cycle test. The superior electrochemical performance originates in the structural stability of the N-doped amorphous carbon shells formed by carbonizing polydopamine.

Synthesis of Fullerenes in Low Pressure Benzene/Oxygen Diffusion Flames

NASA Technical Reports Server (NTRS)

Hebgen, Peter; Howard, Jack B.

1999-01-01

The interest in fullerenes is strongly increasing since their discovery by Kroto et al. in 1985 as products of the evaporation of carbon into inert gas at low pressure. Due to their all carbon closed-shell structure, fullerenes have many exceptional physical and chemical properties and a large potential for applications such as superconductors, sensors, catalysts, optical and electronic devices, polymers, high energy fuels, and biological and medical materials. This list is still growing, because the research on fullerenes is still at an early stage. Fullerenes can be formed not only in a system containing only carbon and an inert gas, but also in premixed hydrocarbon flames under reduced pressure and fuel rich conditions. The highest yields of fullerenes in flames are obtained under conditions of substantial soot formation. There is a need for more information on the yields of fullerenes under different conditions in order to understand the mechanisms of their formation and to enable the design of practical combustion systems for large-scale fullerene production. Little work has been reported on the formation of fullerenes in diffusion flames. In order to explore the yields of fullerenes and the effect of low pressure in diffusion flames, therefore we constructed and used a low pressure diffusion flame burner in this study.

Fullerenes: An extraterrestrial carbon carrier phase for noble gases

PubMed Central

Becker, Luann; Poreda, Robert J.; Bunch, Ted E.

2000-01-01

In this work, we report on the discovery of naturally occurring fullerenes (C60 to C400) in the Allende and Murchison meteorites and some sediment samples from the 65 million-year-old Cretaceous/Tertiary boundary layer (KTB). Unlike the other pure forms of carbon (diamond and graphite), fullerenes are extractable in an organic solvent (e.g., toluene or 1,2,4-trichlorobenzene). The recognition of this unique property led to the detection and isolation of the higher fullerenes in the Kratschmer/Huffmann arc evaporated graphite soot and in the carbon material in the meteorite and impact deposits. By further exploiting the unique ability of the fullerene cage structure to encapsulate and retain noble gases, we have determined that both the Allende and Murchison fullerenes and the KTB fullerenes contain trapped noble gases with ratios that can only be described as extraterrestrial in origin. PMID:10725367

Planar silver nanowire, carbon nanotube and PEDOT:PSS nanocomposite transparent electrodes

PubMed Central

Stapleton, Andrew J; Yambem, Soniya D; Johns, Ashley H; Afre, Rakesh A; Ellis, Amanda V; Shapter, Joe G; Andersson, Gunther G; Quinton, Jamie S; Burn, Paul L; Meredith, Paul

2015-01-01

Highly conductive, transparent and flexible planar electrodes were fabricated using interwoven silver nanowires and single-walled carbon nanotubes (AgNW:SWCNT) in a PEDOT:PSS matrix via an epoxy transfer method from a silicon template. The planar electrodes achieved a sheet resistance of 6.6 ± 0.0 Ω/□ and an average transmission of 86% between 400 and 800 nm. A high figure of merit of 367 Ω−1 is reported for the electrodes, which is much higher than that measured for indium tin oxide and reported for other AgNW composites. The AgNW:SWCNT:PEDOT:PSS electrode was used to fabricate low temperature (annealing free) devices demonstrating their potential to function with a range of organic semiconducting polymer:fullerene bulk heterojunction blend systems. PMID:27877771

Effects of fullerene coalescence on the thermal conductivity of carbon nanopeapods

NASA Astrophysics Data System (ADS)

Li, Jiaqian; Shen, Haijun

2018-05-01

The heat conduction and its dependence on fullerene coalescence in carbon nanopeapods (CNPs) have been investigated by equilibrium molecular dynamics simulations. The effects of fullerene coalescence on the thermal conductivity of CNPs were discussed under different temperatures. It is shown that the thermal conductivity of the CNPs decreases with the coalescence of encapsulated fullerene molecules. The thermal transmission mechanism of the effect of fullerene coalescence was analysed by the mass transfer contribution, the relative contributions of phonon oscillation frequencies to total heat current and the phonon vibrational density of states (VDOS). The mass transfer in CNPs is mainly attributed to the motion of encapsulated fullerene molecule and it gets more restricted with the coalescence of the fullerene. It shows that the low-frequency phonon modes below 20 THz contribute mostly to thermal conductivity in CNPs. The analysis of VDOS demonstrates that the dominating contribution to heat transfer is from the inner fullerene chain. With the coalescence of fullerene, the interfacial heat transfer between the CNT and fullerene chain is strengthened; however, the heat conduction of the fullerene chain decreases more rapidly at the same time.

B38: an all-boron fullerene analogue

NASA Astrophysics Data System (ADS)

Lv, Jian; Wang, Yanchao; Zhu, Li; Ma, Yanming

2014-09-01

Fullerene-like structures formed by elements other than carbon have long been sought. Finding all-boron (B) fullerene-like structures is challenging due to the geometrical frustration arising from competitions among various structural motifs. We report here the prediction of a B38 fullerene analogue found through first-principles swarm structure searching calculations. The structure is highly symmetric and consists of 56 triangles and four hexagons, which provide an optimal void in the center of the cage. Energetically, it is more favorable than the planar and tubular structures, and possesses an unusually high chemical stability: a large energy gap (~2.25 eV) and a high double aromaticity, superior to those of most aromatic quasi-planar B12 and double-ring B20 clusters. Our findings represent a key step forward towards to the understanding of structures of medium-sized B clusters and map out the experimental direction of the synthesis of an all-B fullerene analogue.Fullerene-like structures formed by elements other than carbon have long been sought. Finding all-boron (B) fullerene-like structures is challenging due to the geometrical frustration arising from competitions among various structural motifs. We report here the prediction of a B38 fullerene analogue found through first-principles swarm structure searching calculations. The structure is highly symmetric and consists of 56 triangles and four hexagons, which provide an optimal void in the center of the cage. Energetically, it is more favorable than the planar and tubular structures, and possesses an unusually high chemical stability: a large energy gap (~2.25 eV) and a high double aromaticity, superior to those of most aromatic quasi-planar B12 and double-ring B20 clusters. Our findings represent a key step forward towards to the understanding of structures of medium-sized B clusters and map out the experimental direction of the synthesis of an all-B fullerene analogue. Electronic supplementary information

Electrospinning of Nanofibers for Energy Applications

PubMed Central

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

Organic nanofiber nanosensors

NASA Astrophysics Data System (ADS)

Madsen, M.; Schiek, M.; Thomsen, P.; Andersen, N. L.; Lützen, A.; Rubahn, H.-G.

2007-09-01

A new way of developing optical nanosensors is presented. Organic nanofibers serve as key elements in these new types of devices, which exploit both the smallness and brightness of the nanoaggregates to make new compact and sensitive optical nanosensors. On the basis of bottom up technology, we functionalize individual molecules, which are then intrinsically sensitive to specific agents. These molecules are used as building blocks for controlled growth of larger nanoscaled aggregates. The aggregates in turn can be used as sensing elements on the meso-scale in the size range from hundred nanometers to a few hundred microns. The organic nanofibers thereby might become a versatile tool within nanosensor technology, allowing sensing on the basis of individual molecules over small aggregates to large assemblies. First experiments of Bovine Serum Albumin (BSA) coupling to para-hexaphenyl (p-6P) nanofibers are presented, which could lead towards a new type of protein sensors. Besides large versatility and sensitivity, the nanofibers benefit from the fact that they can be integrated in devices, either in liquids by the use of microfluidic cavities or all in parallel.

Endohedral fullerenes contaning transition-metal clusters

NASA Astrophysics Data System (ADS)

Bhusal, Shusil; Basurto, Luis; Zope, Rajendra; Baruah, Tunna

We report detailed investigation of structural, electronic, and spectroscopic properties of VSc2N-containing fullerenes in the size range C68 - C96. First, the candidate structures of the ground state are obtained using a systematic approach in which a large number of isomers of endohedral fullerenes were screened for their energetic stability. Stability of some of the most promising isomers were further studied using density functional theory at the all-electron level using large polarized Gaussian basis sets. The effect of the V doping is examined on the structure, spin states and the magnetic properties of the endohedral fullerenes. De-SC0002168, NSF-DMR 125302, DE-SC0006818.

Facile preparation and enhanced capacitance of the polyaniline/sodium alginate nanofiber network for supercapacitors.

PubMed

Li, Yingzhi; Zhao, Xin; Xu, Qian; Zhang, Qinghua; Chen, Dajun

2011-05-17

A porous and mat-like polyaniline/sodium alginate (PANI/SA) composite with excellent electrochemical properties was polymerized in an aqueous solution with sodium sulfate as a template. Ultraviolet-visible spectra, X-ray diffraction pattern, and Fourier transform infrared spectra were employed to characterize the PANI/SA composite, indicating that the PANI/SA composite was successfully prepared. The PANI/SA nanofibers with uniform diameters from 50 to 100 nm can be observed on scanning electron microscopy. Cyclic voltammetry and galvanostatic charge/discharge tests were carried out to investigate the electrochemical properties. The PANI/SA nanostructure electrode exhibits an excellent specific capacitance as high as 2093 F g(-1), long cycle life, and fast reflect of oxidation/reduction on high current changes. The remarkable electrochemical characteristic is attributed to the nanostructured electrode materials, which generates a high electrode/electrolyte contact area and short path lengths for electronic transport and electrolyte ion. The approach is simple and can be easily extended to fabricate nanostructural composites for supercapacitor electrode materials.

Electrospun nanofibers: Work for medicine?

NASA Astrophysics Data System (ADS)

Liao, Susan; Chan, Casey K.; Ramakrishna, S.

2010-03-01

Attempts have been made to fabricate nanofibrous scaffolds to mimic the chemical composition and structural properties of the extracellular matrix (ECM) for tissue/organ replacement. Nanofiber scaffolds with various patterns have been successfully produced from synthetic and natural polymers through a relatively simple technique of electrospinning. The resulting patterns can mimic some of the diverse tissue-specific orientation and three-dimensional (3D) fibrous structures. Studies on cell-nanofiber interactions, including studies on stem cells, have revealed the importance of nanotopography on cell adhesion, proliferation and differentiation. Furthermore, clinical application of electrospun nanofibers including wound healing, tissue regeneration, drug delivery and stem cell therapy are highly feasible due to the ease and flexibility of fabrication of making nanofiber with this cost-effective method using electrospinning. In this review, we have highlighted the current state of the art and provided future perspectives on electrospun nanofiber in medical applications.

Generation, Characterization and Applications of Fullerenes

NASA Astrophysics Data System (ADS)

Liu, Shengzhong

A contact-arc sputtering configuration has been adopted and optimized in order to generate fullerene-containing soot. Several stages of design improvements have made our equipment more effective in terms of yield and production rate. Upon modification of Wudl's Soxhlet separation procedure, we have been able to significantly speed up C_ {60} separation and higher fullerene enrichment. At least ten more separable HPLC peaks after C_ {84} have been observed for the first time. Preliminary laser desorption time of flight mass spectra suggest that our enriched higher fullerene sample possibly contains, C_{86}, C_{88}, C_ {90}, C_{92} , C_{94} and C _{96} in addition to the previously isolated smaller fullerenes C_ {60}, C_{70} , C_{76}, C _{78}(D_2), C_{78}(C_ {rm 2v}) and C_{84 }. Among these, C_{86 }, C_{88}, C_{92} show up for the first time in separable amounts and the controversial species --C_{94} appears present too. HPLC has been successfully used for high fullerene separation, pure C_{76}, C_{84} samples so far having been obtained. Fullerene decomposition (especially of higher fullerenes) in the column has been clearly identified. We defined HPLC peaks indicate that the oxidation process may follow certain "well defined" routes. A yellow epoxide band containing various oxides of C_{60 } has been extracted and characterized using mass spectrometry. Characterizations of pure C _{60} and C_{70 } include HPLC, mass spectrometry, vibrational IR and Raman spectroscopy, STM, TEM etc. Our Raman measurements completed the full assignment of C_{60 } fundamental modes and supplied more structural information on C_{70}. STM imaging supplied clear pictures of both C_ {60} and C_{70} molecular topologies. Especially for C _{70}, both the long and the short axes of the molecule have been clearly resolved. TEM observations involving imaging, diffraction and electron energy loss spectroscopy of crystalline C_{60} and C_{70} were performed. The room temperature lattice

Electrospun N-Doped Porous Carbon Nanofibers Incorporated with NiO Nanoparticles as Free-Standing Film Electrodes for High-Performance Supercapacitors and CO2 Capture.

PubMed

Li, Qi; Guo, Jiangna; Xu, Dan; Guo, Jianqiang; Ou, Xu; Hu, Yin; Qi, Haojun; Yan, Feng

2018-04-01

Carbon nanofibers (CNF) with a 1D porous structure offer promising support to encapsulate transition-metal oxides in energy storage/conversion relying on their high specific surface area and pore volume. Here, the preparation of NiO nanoparticle-dispersed electrospun N-doped porous CNF (NiO/PCNF) and as free-standing film electrode for high-performance electrochemical supercapacitors is reported. Polyacrylonitrile and nickel acetylacetone are selected as precursors of CNF and Ni sources, respectively. Dicyandiamide not only improves the specific surface area and pore volume, but also increases the N-doping level of PCNF. Benefiting from the synergistic effect between NiO nanoparticles (NPs) and PCNF, the prepared free-standing NiO/PCNF electrodes show a high specific capacitance of 850 F g -1 at a current density of 1 A g -1 in 6 m KOH aqueous solution, good rate capability, as well as excellent long-term cycling stability. Moreover, NiO NPs dispersed in PCNF and large specific surface area provide many electroactive sites, leading to high CO 2 uptake, and high-efficiency CO 2 electroreduction. The synthesis strategy in this study provides a new insight into the design and fabrication of promising multifunctional materials for high-performance supercapacitors and CO 2 electroreduction. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liposome Formulation of Fullerene-Based Molecular Diagnostic and Therapeutic Agents

PubMed Central

Zhou, Zhiguo

2013-01-01

Fullerene medicine is a new but rapidly growing research subject. Fullerene has a number of desired structural, physical and chemical properties to be adapted for biological use including antioxidants, anti-aging, anti-inflammation, photodynamic therapy, drug delivery, and magnetic resonance imaging contrast agents. Chemical functionalization of fullerenes has led to several interesting compounds with very promising preclinical efficacy, pharmacokinetic and safety data. However, there is no clinical evaluation or human use except in fullerene-based cosmetic products for human skincare. This article summarizes recent advances in liposome formulation of fullerenes for the use in therapeutics and molecular imaging. PMID:24300561

Enhanced performance of flexible dye-sensitized solar cells using flexible Ag@ZrO2/C nanofiber film as low-cost counter electrode

NASA Astrophysics Data System (ADS)

Yin, Xin; Xie, Xueyao; Song, Lixin; Zhai, Jifeng; Du, Pingfan; Xiong, Jie

2018-05-01

Highly flexible ZrO2/C nanofibers (NFs) coated with Ag nanoparticles (NPs) have been fabricated by a combination of electrospinning, carbonization and hydrothermal treatment. The obtained Ag@ZrO2/C NFs serve as low-cost counter electrodes (CEs) for flexible dye-sensitized solar cells (FDSSCs). A considerable power conversion efficiency of 4.77% is achieved, which is 27.9% higher than the η of ZrO2/C NFs CEs (3.73%) and reaches about 90% of that of Pt CE (5.26%). It can be ascribed to the fact that the introduction of Ag NPs provides a large number of accessible reaction sites for electrolyte ions to rapidly participate in the I3-/I- reaction. Moreover, the Ag NPs can produce synergistic effect with ZrO2/C NFs to further enhance transport capacity and electro-catalytic activity of the Ag@ZrO2/C film. Therefore, the considerable performance together with characteristics of simple preparation, low cost and flexibility suggests the Ag@ZrO2/C film can be promising candidate for the future generation of FDSSC.

Biofunctionalized Nanofibers Using Arthrospira (Spirulina) Biomass and Biopolymer

PubMed Central

de Morais, Michele Greque; Stillings, Christopher; Dersch, Roland; Rudisile, Markus; Pranke, Patrícia; Costa, Jorge Alberto Vieira; Wendorff, Joachim

2015-01-01

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. PMID:25667931

Inorganic nanotubes and fullerene-like nanoparticles.

PubMed

Tenne, R

2006-11-01

Although graphite, with its anisotropic two-dimensional lattice, is the stable form of carbon under ambient conditions, on nanometre length scales it forms zero- and one-dimensional structures, namely fullerenes and nanotubes, respectively. This virtue is not limited to carbon and, in recent years, fullerene-like structures and nanotubes have been made from numerous compounds with layered two-dimensional structures. Furthermore, crystalline and polycrystalline nanotubes of pure elements and compounds with quasi-isotropic (three-dimensional) unit cells have also been synthesized, usually by making use of solid templates. These findings open up vast opportunities for the synthesis and study of new kinds of nanostructures with properties that may differ significantly from the corresponding bulk materials. Various potential applications have been proposed for the inorganic nanotubes and the fullerene-like phases. Fullerene-like nanoparticles have been shown to exhibit excellent solid lubrication behaviour, suggesting many applications in, for example, the automotive and aerospace industries, home appliances, and recently for medical technology. Various other potential applications, in catalysis, rechargeable batteries, drug delivery, solar cells and electronics have also been proposed.

Inorganic nanotubes and fullerene-like nanoparticles

NASA Astrophysics Data System (ADS)

Tenne, R.

2006-11-01

Although graphite, with its anisotropic two-dimensional lattice, is the stable form of carbon under ambient conditions, on nanometre length scales it forms zero- and one-dimensional structures, namely fullerenes and nanotubes, respectively. This virtue is not limited to carbon and, in recent years, fullerene-like structures and nanotubes have been made from numerous compounds with layered two-dimensional structures. Furthermore, crystalline and polycrystalline nanotubes of pure elements and compounds with quasi-isotropic (three-dimensional) unit cells have also been synthesized, usually by making use of solid templates. These findings open up vast opportunities for the synthesis and study of new kinds of nanostructures with properties that may differ significantly from the corresponding bulk materials. Various potential applications have been proposed for the inorganic nanotubes and the fullerene-like phases. Fullerene-like nanoparticles have been shown to exhibit excellent solid lubrication behaviour, suggesting many applications in, for example, the automotive and aerospace industries, home appliances, and recently for medical technology. Various other potential applications, in catalysis, rechargeable batteries, drug delivery, solar cells and electronics have also been proposed.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Generation of singlet oxygen in fullerene-containing media: 2. Fullerene-containing solutions

NASA Astrophysics Data System (ADS)

Bagrov, I. V.; Belousova, I. M.; Grenishin, A. S.; Danilov, O. B.; Ermakov, A. V.; Kiselev, V. M.; Kislyakov, I. M.; Murav'eva, T. D.; Sosnov, E. N.

2008-03-01

The generation of singlet oxygen in fullerene solutions is studied by luminescence methods upon excitation by pulsed, repetitively pulsed, and continuous radiation sources. The concentration of singlet oxygen in solutions is measured in stationary and pulsed irradiation regimes. The rate constants of quenching of O2(1Δg) by fullerenes C70 and C60 in the CCl4 solution are measured to be (7.2±0.1)×107 L mol-1 s-1 and less than 6×104 L mol-1 s-1, respectively. The temperature and photolytic variations in the generation properties of the fullerene solution exposed to intense continuous radiation are studied by the methods of optical and EPR spectroscopy. Pulsed irradiation resulted in the production of singlet oxygen in suspensions of fullerene-like structures, in particular, astralenes. A liquid pulsed singlet-oxygen generator based on the fullerene solution in CCl4 is developed and studied, in which the yield of O2 (1Δg) to the gas phase at concentrations up to 5×1016 cm-3 is obtained.

Coaxial fiber supercapacitor using all-carbon material electrodes.

PubMed

Le, Viet Thong; Kim, Heetae; Ghosh, Arunabha; Kim, Jaesu; Chang, Jian; Vu, Quoc An; Pham, Duy Tho; Lee, Ju-Hyuck; Kim, Sang-Woo; Lee, Young Hee

2013-07-23

We report a coaxial fiber supercapacitor, which consists of carbon microfiber bundles coated with multiwalled carbon nanotubes as a core electrode and carbon nanofiber paper as an outer electrode. The ratio of electrode volumes was determined by a half-cell test of each electrode. The capacitance reached 6.3 mF cm(-1) (86.8 mF cm(-2)) at a core electrode diameter of 230 μm and the measured energy density was 0.7 μWh cm(-1) (9.8 μWh cm(-2)) at a power density of 13.7 μW cm(-1) (189.4 μW cm(-2)), which were much higher than the previous reports. The change in the cyclic voltammetry characteristics was negligible at 180° bending, with excellent cycling performance. The high capacitance, high energy density, and power density of the coaxial fiber supercapacitor are attributed to not only high effective surface area due to its coaxial structure and bundle of the core electrode, but also all-carbon materials electrodes which have high conductivity. Our coaxial fiber supercapacitor can promote the development of textile electronics in near future.

Soft-template construction of three-dimensionally ordered inverse opal structure from Li2FeSiO4/C composite nanofibers for high-rate lithium-ion batteries

NASA Astrophysics Data System (ADS)

Li, Donglin; Zhang, Wei; Sun, Ru; Yong, Hong-Tuan-Hua; Chen, Guangqi; Fan, Xiaoyong; Gou, Lei; Mao, Yiyang; Zhao, Kun; Tian, Miao

2016-06-01

Exploring a new method to fabricate small-sized nanofibers is essential to achieve superior performances for energy conversion and storage devices. Here, a novel soft-template strategy is developed to synthesize a three-dimensionally ordered macroporous (3DOM) architecture constructed from small-sized nanofibers. The effectiveness of a nanofiber-assembled three-dimensional inverse opal material as an electrode for high-rate lithium-ion batteries is demonstrated. The small-sized Li2FeSiO4/C composite nanofibers with a diameter of 20-30 nm are grown by employing a tri-block copolymer P123 as a structure directing agent. Accordingly, the macro-mesoporous hierarchical 3DOM architecture constructed from Li2FeSiO4/C nanofibers is further templated from P123 for the nanofibers and a polystyrene colloidal crystal array for the 3DOM architecture. We find that the thermal stability of the nanofiber morphology depends on the self-limited growth of Li2FeSiO4 nanocrystals in a crystalline-amorphous hybrid. As a cathode for a lithium-ion battery, the 3D hierarchical macro-mesoporous cathodes exhibit outstanding high-rate and ultralong-life performances with a capacity retention of 84% after 1500 cycles at 5 C in the voltage window of 1.5-4.5 V, which is greatly improved compared with a simple 3DOM Li2FeSiO4/C nanocomposite.Exploring a new method to fabricate small-sized nanofibers is essential to achieve superior performances for energy conversion and storage devices. Here, a novel soft-template strategy is developed to synthesize a three-dimensionally ordered macroporous (3DOM) architecture constructed from small-sized nanofibers. The effectiveness of a nanofiber-assembled three-dimensional inverse opal material as an electrode for high-rate lithium-ion batteries is demonstrated. The small-sized Li2FeSiO4/C composite nanofibers with a diameter of 20-30 nm are grown by employing a tri-block copolymer P123 as a structure directing agent. Accordingly, the macro

Inorganic nanotubes and fullerene-like materials.

PubMed

Tenne, Reshef

2002-12-02

Following the discovery of fullerenes and carbon nanotubes, it was shown that nanoparticles of inorganic layered compounds, like MoS2, are unstable in the planar form and they form closed cage structures with polyhedral or nanotubular shapes. Various issues on the structure, synthesis, and properties of such inorganic fullerene-like structures are reviewed, together with some possible applications.

Production of silk sericin/silk fibroin blend nanofibers

NASA Astrophysics Data System (ADS)

Zhang, Xianhua; Tsukada, Masuhiro; Morikawa, Hideaki; Aojima, Kazuki; Zhang, Guangyu; Miura, Mikihiko

2011-08-01

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.

Production of silk sericin/silk fibroin blend nanofibers

PubMed Central

2011-01-01

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. PMID:21867508

Simple method for determining fullerene negative ion formation★

NASA Astrophysics Data System (ADS)

Felfli, Zineb; Msezane, Alfred Z.

2018-04-01

A robust potential wherein is embedded the crucial core-polarization interaction is used in the Regge-pole methodology to calculate low-energy electron elastic scattering total cross section for the C60 fullerene in the electron impact energy range 0.02 ≤ E ≤ 10.0 eV. The energy position of the characteristic dramatically sharp resonance appearing at the second Ramsauer-Townsend minimum of the total cross section representing stable C60 - fullerene negative ion formation agrees excellently with the measured electron affinity of C60 [Huang et al., J. Chem. Phys. 140, 224315 (2014)]. The benchmarked potential and the Regge-pole methodology are then used to calculate electron elastic scattering total cross sections for selected fullerenes, from C54 through C240. The total cross sections are found to be characterized generally by Ramsauer-Townsend minima, shape resonances and dramatically sharp resonances representing long-lived states of fullerene negative ion formation. For the total cross sections of C70, C76, C78, and C84 the agreement between the energy positions of the very sharp resonances and the measured electron affinities is outstanding. Additionally, we compare our extracted energy positions of the resultant fullerene anions from our calculated total cross sections of the C86, C90 and C92 fullerenes with the estimated electron affinities ≥3.0 eV by the experiment [Boltalina et al., Rapid Commun. Mass Spectrom. 7, 1009 (1993)]. Resonance energy positions of other fullerenes, including C180 and C240 are also obtained. Most of the total cross sections presented in this paper are the first and only; our novel approach is general and should be applicable to other fullerenes as well and complex heavy atoms, such as the lanthanide atoms. We conclude with a remark on the catalytic properties of the fullerenes through their negative ions.

Nano-Fiber Reinforced Enhancements in Composite Polymer Matrices

NASA Technical Reports Server (NTRS)

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.

Effects of Two Fullerene Derivatives on Monocytes and Macrophages

PubMed Central

Pacor, Sabrina; Grillo, Alberto; Đorđević, Luka; Zorzet, Sonia; Da Ros, Tatiana; Prato, Maurizio

2015-01-01

Two fullerene derivatives (fullerenes 1 and 2), bearing a hydrophilic chain on the pyrrolidinic nitrogen, were developed with the aim to deliver anticancer agents to solid tumors. These two compounds showed a significantly different behaviour on human neoplastic cell lines in vitro in respect to healthy leukocytes. In particular, the pyrrolidinium ring on the fullerene carbon cage brings to a more active compound. In the present work, we describe the effects of these fullerenes on primary cultures of human monocytes and macrophages, two kinds of immune cells representing the first line of defence in the immune response to foreign materials. These compounds are not recognized by circulating monocytes while they get into macrophages. The evaluation of the pronecrotic or proapoptotic effects, analysed by means of analysis of the purinergic receptor P2X7 activation and of ROS scavenging activity, has allowed us to show that fullerene 2, but not its analogue fullerene 1, displays toxicity, even though at concentrations higher than those shown to be active on neoplastic cells. PMID:26090460

Operation of a gated field emitter using an individual carbon nanofiber cathode

NASA Astrophysics Data System (ADS)

Guillorn, M. A.; Melechko, A. V.; Merkulov, V. I.; Ellis, E. D.; Britton, C. L.; Simpson, M. L.; Lowndes, D. H.; Baylor, L. R.

2001-11-01

We report on the operation of an integrated gated cathode device using a single vertically aligned carbon nanofiber as the field emission element. This device is capable of operation in a moderate vacuum for extended periods of time without experiencing a degradation of performance. Less than 1% of the total emitted current is collected by the gate electrode, indicating that the emitted electron beam is highly collimated. As a consequence, this device is ideal for applications that require well-focused electron emission from a microscale structure.

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

PubMed

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.

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

PubMed Central

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

2015-01-01

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. PMID:26621615

Supracolloidal fullerene-like cages: design principles and formation mechanisms.

PubMed

Li, Zhan-Wei; Zhu, You-Liang; Lu, Zhong-Yuan; Sun, Zhao-Yan

2016-11-30

How to create novel desired structures by rational design of building blocks represents a significant challenge in materials science. Here we report a conceptually new design principle for creating supracolloidal fullerene-like cages through the self-assembly of soft patchy particles interacting via directional nonbonded interactions by mimicking non-planar sp 2 hybridized carbon atoms in C 60 . Our numerical investigations demonstrate that the rational design of patch configuration, size, and interaction can drive soft three-patch particles to reversibly self-assemble into a vast collection of supracolloidal fullerene-like cages. We further elucidate the formation mechanisms of supracolloidal fullerene-like cages by analyzing the structural characteristics and the formation process. Our results provide conceptual and practical guidance towards the experimental realization of supracolloidal fullerene-like cages, as well as a new perspective on understanding the fullerene formation mechanisms.

Fullerene (C60) films for solid lubrication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhushan, B.; Gupta, B.K.; Van Cleef, G.W.

1993-10-01

The advent of techniques for producing gram quantities of a new form of stable, pure, solid carbon, designated as fullerene, opens a profusion of possibilities to be explored in many disciplines including tribology. Fullerenes take the form of hollow geodesic domes, which are formed from a network of pentagons and hexagons with covalently bonded carbon atoms. The C60 molecule has the highest possible symmetry (icosahedral) and assumes the shape of a soccer ball. At room temperature, fullerene molecules pack in an fcc lattice bonded with weak van der Waals attractions. Fullerenes can be dissolved in solvents such as toluene andmore » benzene and are easily sublimed. The low surface energy, high chemical stability, spherical shape, weak intermolecular bonding, and high load bearing capacity of C60 molecules offer potential for various mechanical and tribological applications. This paper describes the crystal structure and properties of fullerenes and proposes a mechanism for self-lubricating action. Sublimed films of C60 have been produced and friction and wear performance of these films in various operating environments are the subject of this paper. The results of this study indicate that C60, owing to its unique crystal structure and bonding, may be a promising solid lubricant. 31 refs.« less

Is the Use of Fullerene in Photodynamic Therapy Effective for Atherosclerosis?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nitta, Norihisa, E-mail: r34nitta@belle.shiga-med.ac.jp; Seko, Ayumi; Sonoda, Akinaga

2008-03-15

The purpose of this study was to evaluate Fullerene as a therapeutic photosensitizer in the treatment of atherosclerosis. An atherosclerotic experimental rabbit model was prepared by causing intimal injury to bilateral external iliac arteries using balloon expansion. In four atherosclerotic rabbits and one normal rabbit, polyethylene glycol-modified Fullerene (Fullerene-PEG) was infused into the left external iliac artery and illuminated by light emitting diode (LED), while the right external iliac artery was only illuminated by LED. Two weeks later, the histological findings for each iliac artery were evaluated quantitatively and comparisons were made among atherosclerotic Fullerene+LED artery (n = 4), atheroscleroticmore » light artery (n = 4), normal Fullerene+LED artery (n = 1), and normal light artery (n = 1). An additional two atherosclerotic rabbits were studied by fluorescence microscopy, after Fullerene-PEG-Cy5 complex infusion into the left external iliac artery, for evaluation of Fullerene-PEG incorporated within the atherosclerotic lesions. The degree of atherosclerosis in the atherosclerotic Fullerene+LED artery was significantly (p < 0.05) more severe than that in the atherosclerotic LED artery. No pathological change was observed in normal Fullerene+LED and LED arteries. In addition, strong accumulation of Fullerene-PEG-Cy5 complex within the plaque of the left iliac artery of the two rabbits was demonstrated, in contrast to no accumulation in the right iliac artery. We conclude that infusion of a high concentration of Fullerene-PEG followed by photo-illumination resulted not in a suppression of atherosclerosis but in a progression of atherosclerosis in experimental rabbit models. However, this intervention showed no adverse effects on the normal iliac artery.« less

Rotor-stator molecular crystals of fullerenes with cubane.

PubMed

Pekker, Sándor; Kováts, Eva; Oszlányi, Gábor; Bényei, Gyula; Klupp, Gyöngyi; Bortel, Gábor; Jalsovszky, István; Jakab, Emma; Borondics, Ferenc; Kamarás, Katalin; Bokor, Mónika; Kriza, György; Tompa, Kálmán; Faigel, Gyula

2005-10-01

Cubane (C8H8) and fullerene (C60) are famous cage molecules with shapes of platonic or archimedean solids. Their remarkable chemical and solid-state properties have induced great scientific interest. Both materials form polymorphic crystals of molecules with variable orientational ordering. The idea of intercalating fullerene with cubane was raised several years ago but no attempts at preparation have been reported. Here we show that C60 and similarly C70 form high-symmetry molecular crystals with cubane owing to topological molecular recognition between the convex surface of fullerenes and the concave cubane. Static cubane occupies the octahedral voids of the face-centred-cubic structures and acts as a bearing between the rotating fullerene molecules. The smooth contact of the rotor and stator molecules decreases significantly the temperature of orientational ordering. These materials have great topochemical importance: at elevated temperatures they transform to high-stability covalent derivatives although preserving their crystalline appearance. The size-dependent molecular recognition promises selective formation of related structures with higher fullerenes and/or substituted cubanes.

The first stable lower fullerene: C{sub 36}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piskoti, C.; Zettl, A.

1998-08-01

A new pure carbon material, presumably composed of thirty six carbon atom molecules, has been synthesized and isolated in milligram quantities. It appears as though these molecules have a closed cage structure making them the smallest member of a new class of molecules known as fullerenes, most notably of which is the soccer ball shaped C{sub 60}. However, unlike other known fullerenes, any closed, fullerene-like C{sub 36} cage will necessarily contain fused pentagon rings. Therefore, this molecule apparently violates the isolated pentagon rule, a criterion which requires isolated pentagons for stability in fullerene molecules. Striking parallels between this problem andmore » the synthesis of other fused five member fused ring systems will be discussed. Also, it will be shown that certain biological structures known as clathrin behave in a manner which gives excellent predictions about fullerenes and nanotubes. These predictions help to explain the presence of abundant quantities of C{sub 36} in arced graphite soot. {copyright} {ital 1998 American Institute of Physics.}« less

B38: an all-boron fullerene analogue.

PubMed

Lv, Jian; Wang, Yanchao; Zhu, Li; Ma, Yanming

2014-10-21

Fullerene-like structures formed by elements other than carbon have long been sought. Finding all-boron (B) fullerene-like structures is challenging due to the geometrical frustration arising from competitions among various structural motifs. We report here the prediction of a B38 fullerene analogue found through first-principles swarm structure searching calculations. The structure is highly symmetric and consists of 56 triangles and four hexagons, which provide an optimal void in the center of the cage. Energetically, it is more favorable than the planar and tubular structures, and possesses an unusually high chemical stability: a large energy gap (∼2.25 eV) and a high double aromaticity, superior to those of most aromatic quasi-planar B12 and double-ring B20 clusters. Our findings represent a key step forward towards to the understanding of structures of medium-sized B clusters and map out the experimental direction of the synthesis of an all-B fullerene analogue.

A Hydrogel of Ultrathin Pure Polyaniline Nanofibers: Oxidant-Templating Preparation and Supercapacitor Application.

PubMed

Zhou, Kun; He, Yuan; Xu, Qingchi; Zhang, Qin'e; Zhou, An'an; Lu, Zihao; Yang, Li-Kun; Jiang, Yuan; Ge, Dongtao; Liu, Xiang Yang; Bai, Hua

2018-05-15

Although challenging, fabrication of porous conducting polymeric materials with excellent electronic properties is crucial for many applications. We developed a fast in situ polymerization approach to pure polyaniline (PANI) hydrogels, with vanadium pentoxide hydrate nanowires as both the oxidant and sacrifice template. A network comprised of ultrathin PANI nanofibers was generated during the in situ polymerization, and the large aspect ratio of these PANI nanofibers allowed the formation of hydrogels at a low solid content of 1.03 wt %. Owing to the ultrathin fibril structure, PANI hydrogels functioning as a supercapacitor electrode display a high specific capacitance of 636 F g -1 , a rate capability, and good cycling stability (∼83% capacitance retention after 10,000 cycles). This method was also extended to the preparation of polypyrrole and poly(3,4-ethylenedioxythiophene) hydrogels. This template polymerization method represents a rational strategy for design of conducing polymer networks, which can be readily integrated in high-performance devices or a further platform for functional composites.

Fullerenes, PAH, Carbon Nanostructures, and Soot in Low Pressure Diffusion Flames

NASA Technical Reports Server (NTRS)

Grieco, William J.; Lafleur, Arthur L.; Rainey, Lenore C.; Taghizadeh, Koli; VanderSande, John B.; Howard, Jack B.

1997-01-01

The formation of fullerenes C60 and C7O is known to occur in premixed laminar benzene/oxygen/argon flames operated at reduced pressures. High resolution transmission electron microscopy (HRTEM) images of material collected from these flames has identified a variety of multishelled nanotubes and fullerene 'onions' as well as some trigonous structures. These fullerenes and nanostructures resemble the material that results from commercial fullerene production systems using graphite vaporization. As a result, combustion is an interesting method for fullerenes synthesis. If commercial scale operation is to be considered, the use of diffusion flames might be safer and less cumbersome than premixed flames. However, it is not known whether diffusion flames produce the types and yields of fullerenes obtained from premixed benzene/oxygen flames. Therefore, the formation of fullerenes and carbon nanostructures, as well as polycyclic aromatic hydrocarbons (PAH) and soot, in acetylene and benzene diffusion flames is being studied using high performance liquid chromatography (HPLC) and high resolution transmission electron microscopy (HRTEM).

C60 fullerene binding to DNA

NASA Astrophysics Data System (ADS)

Alshehri, Mansoor H.; Cox, Barry J.; Hill, James M.

2014-09-01

Fullerenes have attracted considerable attention in various areas of science and technology. Owing to their exceptional physical, chemical, and biological properties, they have many applications, particularly in cosmetic and medical products. Using the Lennard-Jones 6-12 potential function and the continuum approximation, which assumes that intermolecular interactions can be approximated by average atomic surface densities, we determine the binding energies of a C60 fullerene with respect to both single-strand and double-strand DNA molecules. We assume that all configurations are in a vacuum and that the C60 fullerene is initially at rest. Double integrals are performed to determine the interaction energy of the system. We find that the C60 fullerene binds to the double-strand DNA molecule, at either the major or minor grooves, with binding energies of -4.7 eV or -2.3 eV, respectively, and that the C60 molecule binds to the single-strand DNA molecule with a binding energy of -1.6 eV. Our results suggest that the C60 molecule is most likely to be linked to the major groove of the dsDNA molecule.

Nickel nanofibers synthesized by the electrospinning method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ji, Yi; Zhang, Xuebin, E-mail: zzhhxxbb@126.com; Zhu, Yajun

2013-07-15

Highlights: ► The nickel nanofibers have been obtained by electrospinning method. ► The nickel nanofibers had rough surface which was consisted of mass nanoparticles. ► The average diameter of nickel nanofibers is about 135 nm and high degree of crystallization. ► The Hc, Ms, and Mr were estimated to be 185 Oe, 51.9 and 16.9 emu/g respectively. - Abstract: In this paper, nickel nanofibers were prepared by electrospinning polyvinyl alcohol/nickel nitrate precursor solution followed by high temperature calcination in air and deoxidation in hydrogen atmosphere. The thermal stability of the as-electrospun PVA/Ni(NO{sub 3}){sub 2} composite nanofibers were characterized by TG–DSC.more » The morphologies and structures of the as-prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electronmicroscope (FE-SEM) and field-emission transmission electron microscopy (FE-TEM). The hysteresis loops (M–H loops) were measured by Physical Property Measurement System (PPMS). The results indicate that: the PVA and the nickel nitrate were almost completely decomposed at 460 °C and the products were pure nickel nanofibers with face-centered cubic (fcc) structure. Furthermore, the as-prepared nickel nanofibers had a continuous structure with rough surface and high degree of crystallization. The average diameter of nickel nanofibers was about 135 nm. The nanofibers showed a stronger coercivity of 185 Oe than value of bulk nickel.« less

A minitablet formulation made from electrospun nanofibers.

PubMed

Poller, Bettina; Strachan, Clare; Broadbent, Roland; Walker, Greg F

2017-05-01

The purpose of this study was to evaluate electrospun drug loaded nanofibers as a new matrix for minitablets. Prednisone, a poorly water-soluble drug, was loaded into povidone (polyvinylpyrrolidone, PVP) nanofibers using the process of electrospinning. The drug-loaded nanofiber mat was compressed into minitablets with a 2mm diameter and a height of 2.63±0.04mm. SEM analysis of the minitablet identified a nano-web structure with a nanofiber diameter in the range of 400-500nm. The minitablets met the requirements of the US Pharmacopeia with respect to content uniformity and friability. DSC and XRPD analysis of the minitablet indicated that the drug-polymer mixture was a one-phase amorphous system. XRPD analysis of the drug loaded nanofiber mat after 10-months of storage at ambient temperature showed no evidence of recrystallization of the drug. Solubility and dissolution properties of the drug formulated into a nanofiber mat and minitablet were evaluated. These results show that electrospun nanofibers may provide a useful matrix for the further development of minitablets. Copyright © 2017 Elsevier B.V. All rights reserved.

Smart bi-metallic perovskite nanofibers as selective and reusable sensors of nano-level concentrations of non-steroidal anti-inflammatory drugs.

PubMed

Mohamed, Mona A; Hasan, Menna M; Abdullah, Ibrahim H; Abdellah, Ahmed M; Yehia, Ali M; Ahmed, Nashaat; Abbas, Walaa; Allam, Nageh K

2018-08-01

A strategy for trace-level carbon-based electrochemical sensors is investigated via exploring the interesting properties of BaNb 2 O 6 nanofibers (NFs). Utilizing adsorptive stripping square wave voltammetry (ASSWV), an electrochemical sensing platform was developed based on BaNb 2 O 6 nanofibers-modified carbon paste electrode (CPE) for the sensitive detection of lornoxicam (LOR). Different techniques were used to characterize the fabricated BaNb 2 O 6 perovskite NFs. The obtained data show the feasibility to electro-oxidize LOR and paracetamol (PAR) on the surface of the fabricated sensor. The amount of nanofiber and testing conditions were optimized using response surface methodology and ASSWV technique. The optimized BaNb 2 O 6 /CPE sensor exhibits low detection limit of 6.39 × 10 -10 mol L -1 , even in the presence of the co-formulated drug paracetamol (PAR). The sensor was successfully applied for biological applications. Copyright © 2018 Elsevier B.V. All rights reserved.

Implications of fullerene-60 upon in-vitro LDPE biodegradation.

PubMed

Sah, Aditi; Kapri, Anil; Zaidi, M G H; Negi, Harshita; Goel, Reeta

2010-05-01

Fullerene-60 nanoparticles were used for studying their influence upon the LDPE biodegradation efficiency of two potential polymer-degrading consortia comprising of three bacterial strains each. At a concentration of 0.01% (w/v) in minimal broth lacking dextrose, fullerene did not have any negative influence upon the consortial growth. However, fullerene was found to be detrimental for bacterial growth at higher concentrations (viz. 0.25%, 0.5% and 1%). Although, addition of 0.01% fullerene into the biodegradation assays containing 5 mg/ml LDPE subsided growth-curves significantly, but subsequent analysis of degraded products revealed enhanced biodegradation. Fourier transform infrared spectroscopy (FT-IR) revealed breakage and formation of chemical bonds along with introduction of nu C-O frequencies into hydrocarbon backbone of LDPE. Further, simultaneous thermogravimetric-differential thermogravimetry-differential thermal analysis (TG-DTG-DTA) revealed higher number of decomposition steps along with a 1,000-fold decrease in the heat of reactions (DeltaH) in fullerene-assisted biodegraded LDPE suggesting probable formation of multiple, macromolecular by-products. This is the first report whereby fullerene-60, which is otherwise considered toxic, has helped to alleviate polymer biodegradation process of bacterial consortia.

Photodynamic therapy with fullerenes in vivo: reality or a dream?

PubMed

Sharma, Sulbha K; Chiang, Long Y; Hamblin, Michael R

2011-12-01

Photodynamic therapy (PDT) employs the combination of nontoxic photosensitizers and visible light that is absorbed by the chromophore to produce long-lived triplet states that can carry out photochemistry in the presence of oxygen to kill cells. The closed carbon-cage structure found in fullerenes can act as a photosensitizer, especially when functionalized to impart water solubility. Although there are reports of the use of fullerenes to carry out light-mediated destruction of viruses, microorganisms and cancer cells in vitro, the use of fullerenes to mediate PDT of diseases such as cancer and infections in animal models is less well developed. It has recently been shown that fullerene PDT can be used to save the life of mice with wounds infected with pathogenic Gram-negative bacteria. Fullerene PDT has also been used to treat mouse models of various cancers including disseminated metastatic cancer in the peritoneal cavity. In vivo PDT with fullerenes represents a new application in nanomedicine.

Polymer nanofiber-carbon nanotube network generating circuits

NASA Astrophysics Data System (ADS)

Mutlu, Mustafa Umut; Akın, Osman; Yildiz, Ümit Hakan

2018-02-01

The polymer nanofiber carbon nanotube (CNT) based devices attracts attention since they promise high performance for next generation devices such as wearable electronics, ultra-light weighted appliances and foldable devices. This abstract describes the utilization of polymer nanofibers and CNT as major component of low cost foldable photo-resistor. We use polymer nanofiber as template guiding CNTs to generate nanocircuits and conductive sensing network. The controlled combination of CNTs and polymer nanofibers provide opportunities for device miniaturization without loss of performance. The nanofiber-CNT network based photo-resistor exhibits broad band response 400 to 1600 nm that holding promises for ultra-thin devices and new sensing platforms.

Thermal conductivity model for nanofiber networks

NASA Astrophysics Data System (ADS)

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.

Effect of Self-Assembly of Fullerene Nano-Particles on Lipid Membrane

PubMed Central

Zhang, Saiqun; Mu, Yuguang; Zhang, John Z. H.; Xu, Weixin

2013-01-01

Carbon nanoparticles can penetrate the cell membrane and cause cytotoxicity. The diffusion feature and translocation free energy of fullerene through lipid membranes is well reported. However, the knowledge on self-assembly of fullerenes and resulting effects on lipid membrane is poorly addressed. In this work, the self-assembly of fullerene nanoparticles and the resulting influence on the dioleoylphosphtidylcholine (DOPC) model membrane were studied by using all-atom molecular dynamics simulations with explicit solvents. Our simulation results confirm that gathered small fullerene cluster can invade lipid membrane. Simulations show two pathways: 1) assembly process is completely finished before penetration; 2) assembly process coincides with penetration. Simulation results also demonstrate that in the membrane interior, fullerene clusters tend to stay at the position which is 1.0 nm away from the membrane center. In addition, the diverse microscopic stacking mode (i.e., equilateral triangle, tetrahedral pentahedral, trigonal bipyramid and octahedron) of these small fullerene clusters are well characterized. Thus our simulations provide a detailed high-resolution characterization of the microscopic structures of the small fullerene clusters. Further, we found the gathered small fullerene clusters have significant adverse disturbances to the local structure of the membrane, but no great influence on the global integrity of the lipid membrane, which suggests the prerequisite of high-content fullerene for cytotoxicity. PMID:24204827

Complexation of C60 fullerene with aromatic drugs.

PubMed

Evstigneev, Maxim P; Buchelnikov, Anatoly S; Voronin, Dmitry P; Rubin, Yuriy V; Belous, Leonid F; Prylutskyy, Yuriy I; Ritter, Uwe

2013-02-25

The contributions of various physical factors to the energetics of complexation of aromatic drug molecules with C(60) fullerene are investigated in terms of the calculated magnitudes of equilibrium complexation constants and the components of the net Gibbs free energy. Models of complexation are developed taking into account the polydisperse nature of fullerene solutions in terms of the continuous or discrete (fractal) aggregation of C(60) molecules. Analysis of the energetics has shown that stabilization of the ligand-fullerene complexes in aqueous solution is mainly determined by intermolecular van der Waals interactions and, to lesser extent, by hydrophobic interactions. The results provide a physicochemical basis for a potentially new biotechnological application of fullerenes as modulators of biological activity of aromatic drugs. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photophysical Properties and Singlet Oxygen Generation Efficiencies of Water-Soluble Fullerene Nanoparticles

PubMed Central

Stasheuski, Alexander S; Galievsky, Victor A; Stupak, Alexander P; Dzhagarov, Boris M; Choi, Mi Jin; Chung, Bong Hyun; Jeong, Jin Young

2014-01-01

As various fullerene derivatives have been developed, it is necessary to explore their photophysical properties for potential use in photoelectronics and medicine. Here, we address the photophysical properties of newly synthesized water-soluble fullerene-based nanoparticles and polyhydroxylated fullerene as a representative water-soluble fullerene derivative. They show broad emission band arising from a wide-range of excitation energies. It is attributed to the optical transitions from disorder-induced states, which decay in the nanosecond time range. We determine the kinetic properties of the singlet oxygen (1O2) luminescence generated by the fullerene nanoparticles and polyhydroxylated fullerene to consider the potential as photodynamic agents. Triplet state decay of the nanoparticles was longer than 1O2 lifetime in water. Singlet oxygen quantum yield of a series of the fullerene nanoparticles is comparably higher ranging from 0.15 to 0.2 than that of polyhydroxylated fullerene, which is about 0.06. PMID:24893622

Polymeric Nanofibers in Tissue Engineering

PubMed Central

Dahlin, Rebecca L.; Kasper, F. Kurtis

2011-01-01

Polymeric nanofibers can be produced using methods such as electrospinning, phase separation, and self-assembly, and the fiber composition, diameter, alignment, degradation, and mechanical properties can be tailored to the intended application. Nanofibers possess unique advantages for tissue engineering. The small diameter closely matches that of extracellular matrix fibers, and the relatively large surface area is beneficial for cell attachment and bioactive factor loading. This review will update the reader on the aspects of nanofiber fabrication and characterization important to tissue engineering, including control of porous structure, cell infiltration, and fiber degradation. Bioactive factor loading will be discussed with specific relevance to tissue engineering. Finally, applications of polymeric nanofibers in the fields of bone, cartilage, ligament and tendon, cardiovascular, and neural tissue engineering will be reviewed. PMID:21699434

Fabrication and characterization of differentiated aramid nanofibers and transparent films

NASA Astrophysics Data System (ADS)

Luo, Jingjing; Zhang, Meiyun; Yang, Bin; Liu, Guodong; Song, Shunxi

2018-03-01

Aramid nanofibers (ANFs) frequently are employed as versatile building blocks for constructing high-performance nanocomposites due to its structural and performance superiority. In this paper, the different ANFs and ANF films derived from the typical aramid yarns, chopped fiber, pulp fiber and fibrid fiber, respectively, were fabricated through deprotonation with potassium hydroxide in dimethyl sulphoxide, protonation with deionized water and vacuum-assisted filtration. The physical tests such as tensile test, ultraviolet transmittance and absorbance, thermogravimetric analysis were executed to evaluate and contrast the thermodynamic and optical performances of these differentiated ANFs and ANF films. The analytical results suggested that ANFs films prepared by the different forms of aramid macrofibers presented with differentiated properties such as mechanical behaviors, transparencies and flexibilities. And also it was found that the oversized nanofiber in length led to the formation of flocculation which was adverse for ANFs films in the formation of high strength. Whereas, small diameter just facilitated for the achievement of high stiffness and transparency. By contrast, the ANFs films made from chopped nanofiber, with aspect ratio of 200-500, exhibited good transparency, thermal stability and mechanical properties with transmittance value of 83%, TG10% around 521 °C, ultimate strength (σ) of 103.41 MPa, stiffness (E) of 4.70 GPa and strain at break of 5.56%. This work offers an alternative nanoscale building block as an effective nanofiller for preparing high-performance nanocomposites with different requirements in the potential fields such as transparent coating and flexible electrode or display materials, battery separator and microporous membrane.

Structural models of inorganic fullerene-like structures

NASA Astrophysics Data System (ADS)

Ascencio, J. A.; Perez-Alvarez, M.; Molina, L. M.; Santiago, P.; José-Yacaman, M.

2003-03-01

In the study of fullerene-like structures, some of the more interesting systems are the inorganic cages, made of MoS 2 (usually named inorganic fullerenes), which have many important potential applications as lubricant and catalysts. In the present work, we report calculations for structural models of closed cage of inorganic fullerene-like structures for MoS 2 system. Three cage shapes were found to be the most stable: triangular pyramid, octahedron and dodecahedron. High resolution TEM images of MoS 2 cages structures were calculated to be compared with experimental data. Some examples of triangular pyramid and polyhedron in experimental MoS 2 samples are presented.

The study of dielectric properties of the endohedral fullerenes

NASA Astrophysics Data System (ADS)

Bhusal, Shusil

Dielectric response of the metal nitride fullerenes is studied using the density functional theory at the all-electron level using generalized gradient approximation. The dielectric response is studied by computing the static dipole polarizabilities using the finite field method, i.e. by numerically differentiating the dipole moments with respect to electric field. The endohedral fullerenes studied in this work are Sc3N C68(6140), Sc3N C68(6146), Sc3N C70(7854), Sc3N C70(7960), Sc3N C76(17490), Sc3N C78(22010), Sc3N C80(31923), Sc3N C80(31924), Sc3N C82(39663), Sc3N C90(43), Sc3N C90(44), Sc3N C92(85), Sc3N C94(121), Sc3N C96(186), Sc3N C98(166). Using the Voronoi and Hirschfield approaches as implemented in our NRLMOL code, we determine the atomic contributions to the total polarizability. The site-specific contributions to the polarizability of endohedral fullerenes allowed us to determine the polarizability of two subsystems: the fullerene shell and the encapsulated Sc3N unit. Our results showed that the contributions to the total polarizability from the encapsulated Sc3N units are vanishingly small. Thus, the total polarizability of the endohedral fullerene is almost entirely due to the outer fullerene shell. These fullerenes are excellent molecular models of a Faraday cage.

Silicon Whisker and Carbon Nanofiber Composite Anode

NASA Technical Reports Server (NTRS)

Ma, Junqing (Inventor); Newman, Aron (Inventor); Lennhoff, John (Inventor)

2015-01-01

A carbon nanofiber can have a surface and include at least one crystalline whisker extending from the surface of the carbon nanofiber. A battery anode composition can be formed from a plurality of carbon nanofibers each including a plurality of crystalline whiskers.

Ultrasonic-assisted dyeing of Nylon-6 nanofibers.

PubMed

Jatoi, Abdul Wahab; Ahmed, Farooq; Khatri, Muzamil; Tanwari, Anwaruddin; Khatri, Zeeshan; Lee, Hoik; Kim, Ick Soo

2017-11-01

We first time report ultrasonic dyeing of the Nylon 6 nanofibers with two disperse dyes CI Disperse blue 56 and CI Disperse Red 167:1 by utilising ultrasonic energy during dyeing process. The Nylon 6 nanofibers were fabricated via electrospinning and dyed via batchwise method with and without sonication. Results revealed that ultrasonic dyeing produce higher color yield (K/S values) and substantially reduces dyeing time from 60min for conventional dyeing to 30min can be attributed to breakage of dye aggregate, transient cavitation near nanofiber surface and mass transfer within/between nanofibers. Color fastness results exhibited good to very good dye fixation. SEM images exhibit insignificant effect of sonication on morphology of the nanofibers. Our research results demonstrate ultrasonic dyeing as a better dyeing technique for Nylon 6 nanofibers with higher color yield and substantially reduced dyeing time. Copyright © 2017 Elsevier B.V. All rights reserved.

Encapsulating Silica/Antimony into Porous Electrospun Carbon Nanofibers with Robust Structure Stability for High-Efficiency Lithium Storage.

PubMed

Wang, Hongkang; Yang, Xuming; Wu, Qizhen; Zhang, Qiaobao; Chen, Huixin; Jing, Hongmei; Wang, Jinkai; Mi, Shao-Bo; Rogach, Andrey L; Niu, Chunming

2018-04-24

To address the volume-change-induced pulverization problems of electrode materials, we propose a "silica reinforcement" concept, following which silica-reinforced carbon nanofibers with encapsulated Sb nanoparticles (denoted as SiO 2 /Sb@CNFs) are fabricated via an electrospinning method. In this composite structure, insulating silica fillers not only reinforce the overall structure but also contribute to additional lithium storage capacity; encapsulation of Sb nanoparticles into the carbon-silica matrices efficiently buffers the volume changes during Li-Sb alloying-dealloying processes upon cycling and alleviates the mechanical stress; the porous carbon nanofiber framework allows for fast charge transfer and electrolyte diffusion. These advantageous characteristics synergistically contribute to the superior lithium storage performance of SiO 2 /Sb@CNF electrodes, which demonstrate excellent cycling stability and rate capability, delivering reversible discharge capacities of 700 mA h/g at 200 mA/g, 572 mA h/g at 500 mA/g, and 468 mA h/g at 1000 mA/g each after 400 cycles. Ex situ as well as in situ TEM measurements confirm that the structural integrity of silica-reinforced Sb@CNF electrodes can efficiently withstand the mechanical stress induced by the volume changes. Notably, the SiO 2 /Sb@CNF//LiCoO 2 full cell delivers high reversible capacities of ∼400 mA h/g after 800 cycles at 500 mA/g and ∼336 mA h/g after 500 cycles at 1000 mA/g.

UV-responsive polyvinyl alcohol nanofibers prepared by electrospinning

NASA Astrophysics Data System (ADS)

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

2015-07-01

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.

Selective voltammetric determination of Cd(II) by using N,S-codoped porous carbon nanofibers.

PubMed

Gao, Sanshuang; Liu, Jing; Luo, Jun; Mamat, Xamxikamar; Sambasivam, Sangaraju; Li, Yongtao; Hu, Xun; Wågberg, Thomas; Hu, Guangzhi

2018-05-05

Porous carbon nanofibers codoped with nitrogen and sulfur (NFs) were prepared by pyrolysis of trithiocyanuric acid, silica nanospheres and polyacrylonitrile (PAN) followed by electrospinning. The NFs were used to modify a glassy carbon electrode (GCE) which then displayed highly sensitive response to traces of Cd(II). Compared to a bare GCE and a Nafion modified GCE, the GCE modified with codoped NFs shows improved sensitivity for Cd(II) in differential pulse anodic sweep voltammetry. The stripping peak current (typically measured at 0.81 V vs. Ag/AgCl) increases linearly in the 2.0-500 μg·L -1 Cd(II) concentration range. This is attributed to the large surface area (109 m 2 ·g -1 ), porous structure, and high fraction of heteroatoms (19 at.% of N and 0.75 at.% of S). The method was applied to the determination of Cd(II) in (spiked) tap water where it gave recoveries that ranged between 96% and 103%. Graphical abstract Schematic of a glassy carbon electrode (GCE) modified with N- and S-codoped porous carbon nanofibers (N,S-PCNFs). This GCE has good selectivity for cadmium ion (Cd 2+ ) which can be determined by differential pulse anodic sweeping voltammetry (DPASV) with a detection limit as low as 0.7 ng·mL -1 .

Thermal conductivity model for nanofiber networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Xinpeng; Huang, Congliang; Liu, Qingkun

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 ismore » 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.« less

Battery Electrode Materials with High Cycle Lifetimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prof. Brent Fultz

2001-06-29

In an effort to understand the capacity fade of nickel-metal hydride (Ni-MH) batteries, we performed a systematic study of the effects of solute additions on the cycle life of metal hydride electrodes. We also performed a series of measurements on hydrogen absorption capacities of novel carbon and graphite-based materials including graphite nanofibers and single-walled carbon nanotubes. Towards the end of this project we turned our attention to work on Li-ion cells with a focus on anode materials.

Binding S0.6 Se0.4 in 1D Carbon Nanofiber with CS Bonding for High-Performance Flexible Li-S Batteries and Na-S Batteries.

PubMed

Yao, Yu; Zeng, Linchao; Hu, Shuhe; Jiang, Yu; Yuan, Beibei; Yu, Yan

2017-05-01

A one-step synthesis procedure is developed to prepare flexible S 0.6 Se 0.4 @carbon nanofibers (CNFs) electrode by coheating S 0.6 Se 0.4 powder with electrospun polyacrylonitrile nanofiber papers at 600 °C. The obtained S 0.6 Se 0.4 @CNFs film can be used as cathode material for high-performance Li-S batteries and room temperature (RT) Na-S batteries directly. The superior lithium/sodium storage performance derives from its rational structure design, such as the chemical bonding between Se and S, the chemical bonding between S 0.6 Se 0.4 and CNFs matrix, and the 3D CNFs network. This easy one-step synthesis procedure provides a feasible route to prepare electrode materials for high-performance Li-S and RT Na-S batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of morphology-controllable polyaniline and polyaniline/graphene hydrogels for high performance binder-free supercapacitor electrodes

NASA Astrophysics Data System (ADS)

Luo, Jinwei; Zhong, Wenbin; Zou, Yubo; Xiong, Changlun; Yang, Wantai

2016-07-01

Polyaniline (PANI) and its composite hydrogels have been considered as a unique supercapacitor electrode material due to their three dimensional (3D) porous structures, formed conducting networks, high specific surface areas and fast electron/ion transfer. Herein, dendritic and long fibrous PANI nanostructure hydrogels (PDH and PFH), dendritic PNAI nanofiber/graphene and long PANI nanofibers/Nitrogen-doped graphene composite hydrogels (PGH and PNGH) were prepared by integration polymerization of aniline and hydrothermal process. It was found that the addition of p-Phenylenediamine (PPD) not only controlled the morphologies of PANI from dendritic to long fibrous, but also facilitated the graphene oxide (GO) into nitrogen-doped graphene. Furthermore, after freeze-drying, PDH and PGH exhibited a max compressive strength of 9.5 and 9.6 KPa, respectively; while the max compressive strength of PFH and PNGH constructed with long PANI nanofiber is 79.9 and 75.8 KPa, respectively. Directly using these prepared hydrogels as electrodes for supercapacitors, it was found that PDH, PFH, PGH and PNGH exhibited high specific capacitances of 448.6, 470, 540.9 and 610 F g-1, respectively, at the current density of 1 A g-1. It is expected that the prepared PDH, PFH, PGH and PNGH can be directly applied in the field of high performance energy storage devices.

Magnetic nanofiber composite materials and devices using same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Xing; Zhou, Ziyao

2017-04-11

A nonreciprocal device is described. It includes a housing, a waveguide layer and at least one layer of magnetic nanofiber composite. The magnetic nanofiber composite layer is made up of a polymer base layer, a dielectric matrix comprising magnetic nanofibers. The nanofibers have a high aspect ratio and wherein said dielectric matrix is embedded in the polymer base layer.

Fullerene data mining using bibliometrics and database tomography

PubMed

Kostoff; Braun; Schubert; Toothman; Humenik

2000-01-01

Database tomography (DT) is a textual database analysis system consisting of two major components: (1) algorithms for extracting multiword phrase frequencies and phrase proximities (physical closeness of the multiword technical phrases) from any type of large textual database, to augment (2) interpretative capabilities of the expert human analyst. DT was used to derive technical intelligence from a fullerenes database derived from the Science Citation Index and the Engineering Compendex. Phrase frequency analysis by the technical domain experts provided the pervasive technical themes of the fullerenes database, and phrase proximity analysis provided the relationships among the pervasive technical themes. Bibliometric analysis of the fullerenes literature supplemented the DT results with author/journal/institution publication and citation data. Comparisons of fullerenes results with past analyses of similarly structured near-earth space, chemistry, hypersonic/supersonic flow, aircraft, and ship hydrodynamics databases are made. One important finding is that many of the normalized bibliometric distribution functions are extremely consistent across these diverse technical domains and could reasonably be expected to apply to broader chemical topics than fullerenes that span multiple structural classes. Finally, lessons learned about integrating the technical domain experts with the data mining tools are presented.

Picosecond laser ablation of polyamide electrospun nanofibers

NASA Astrophysics Data System (ADS)

Götze, Marco; Krimig, Olaf; Kürbitz, Tobias; Henning, Sven; Heilmann, Andreas; Hillrichs, Georg

2017-02-01

Electrospun nanofibers mats have a great potential in tissue engineering and regenerative medicine. Their high porosity and enormous volume to surface ratio stimulate the growth and adhesion of mammalian cells and serve as a stable support structure. These suitable properties can be further optimized by structuring of the nanofibers. Ultrashort pulsed lasers can be used for modifying of the electrospun nanofibers without significant heat exposure. It seems also possible to generate very fine cuts from the fiber mats. In this study, polyamide electrospun nanofibers samples were processed with picosecond UV-laser irradiation (λ = 355 nm, τ = 15 ps). The samples were processed in dry, wet and immersed condition. To optimize cutting and structuring of nanofiber tissue flakes, the influence of different laser parameters on line widths, edge quality, heat-affected zone (HAZ) and the contamination of the fibers by ablated particles (debris) were examined. One additional aim was the minimization of the flake size. It was possible to generate nanofiber flakes in the sub-millimeter range. The quality of the nanofiber flakes could be improved by ablation near the ablation threshold of the material. For cutting under wet conditions shrinking of the flakes has to be taken into account.

High-rate nano-crystalline Li 4Ti 5O 12 attached on carbon nano-fibers for hybrid supercapacitors

NASA Astrophysics Data System (ADS)

Naoi, Katsuhiko; Ishimoto, Shuichi; Isobe, Yusaku; Aoyagi, Shintaro

A lithium titanate (Li 4Ti 5O 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 4Ti 5O 12 electrode has a unique nano-structure consisting of unusually small nano-crystalline Li 4Ti 5O 12 (ca. 5-20 nm) grafted onto carbon nano-fiber anchors (nc-Li 4Ti 5O 12/CNF). This nano-structured nc-Li 4Ti 5O 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 4Ti 5O 12/CNF composite electrode and a positive activated carbon electrode showed high energy density of 40 Wh L -1 and high power density of 7.5 kW L -1 comparable to conventional EDLCs.

Paper Models for Fullerenes C60-C84.

ERIC Educational Resources Information Center

Beaton, John M.

1995-01-01

Describes a system to construct paper models of all 51 of the possible fullerene isomers from C60 through C84. Provides students, teachers, and specialists with an inexpensive mechanism to follow the literature interplay on fullerene structures. (JRH)

Efficient Regular Perovskite Solar Cells Based on Pristine [70]Fullerene as Electron-Selective Contact.

PubMed

Collavini, Silvia; Kosta, Ivet; Völker, Sebastian F; Cabanero, German; Grande, Hans J; Tena-Zaera, Ramón; Delgado, Juan Luis

2016-06-08

[70]Fullerene is presented as an efficient alternative electron-selective contact (ESC) for regular-architecture perovskite solar cells (PSCs). A smart and simple, well-described solution processing protocol for the preparation of [70]- and [60]fullerene-based solar cells, namely the fullerene saturation approach (FSA), allowed us to obtain similar power conversion efficiencies for both fullerene materials (i.e., 10.4 and 11.4 % for [70]- and [60]fullerene-based devices, respectively). Importantly, despite the low electron mobility and significant visible-light absorption of [70]fullerene, the presented protocol allows the employment of [70]fullerene as an efficient ESC. The [70]fullerene film thickness and its solubility in the perovskite processing solutions are crucial parameters, which can be controlled by the use of this simple solution processing protocol. The damage to the [70]fullerene film through dissolution during the perovskite deposition is avoided through the saturation of the perovskite processing solution with [70]fullerene. Additionally, this fullerene-saturation strategy improves the performance of the perovskite film significantly and enhances the power conversion efficiency of solar cells based on different ESCs (i.e., [60]fullerene, [70]fullerene, and TiO2 ). Therefore, this universal solution processing protocol widens the opportunities for the further development of PSCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High Photoelectric Conversion Efficiency of Metal Phthalocyanine/Fullerene Heterojunction Photovoltaic Device

PubMed Central

Lin, Chi-Feng; Zhang, Mi; Liu, Shun-Wei; Chiu, Tien-Lung; Lee, Jiun-Haw

2011-01-01

This paper introduces the fundamental physical characteristics of organic photovoltaic (OPV) devices. Photoelectric conversion efficiency is crucial to the evaluation of quality in OPV devices, and enhancing efficiency has been spurring on researchers to seek alternatives to this problem. In this paper, we focus on organic photovoltaic (OPV) devices and review several approaches to enhance the energy conversion efficiency of small molecular heterojunction OPV devices based on an optimal metal-phthalocyanine/fullerene (C60) planar heterojunction thin film structure. For the sake of discussion, these mechanisms have been divided into electrical and optical sections: (1) Electrical: Modification on electrodes or active regions to benefit carrier injection, charge transport and exciton dissociation; (2) Optical: Optional architectures or infilling to promote photon confinement and enhance absorption. PMID:21339999

Fullerene ion chemistry: a journey of discovery and achievement

PubMed Central

Böhme, Diethard K.

2016-01-01

An account is provided of the extraordinary features of buckminster fullerene cations and their chemistry that we discovered in our Ion Chemistry Laboratory at York University (Canada) during a ‘golden’ period of research in the early 1990s, just after C60 powder became available. We identified new chemical ways of C60 ionization and tracked novel chemistry of C60n+ as a function of charge state (n=1–3) with some 50 different reagent molecules. We found that multiple charges enhance reaction rates and diversify reaction products and mechanisms. Strong electrostatic interactions with reagent molecules were seen to reduce barriers to carbon surface bonding and charge-separation reactions, while intramolecular Coulomb repulsion appeared to localize charge on the surface or the substituent and so influence higher order chemistry, including ‘spindle’, ‘star’, ‘fuzzy ball’, ‘ball-and-chain’ and dimer ion formation. We introduced the notion of ‘apparent’ gas-phase acidity with measurements of proton-transfer reactions of multiply charged fullerene cations. We also explored the attachment of atomic metal cations to C60 and their subsequent reactions. All these findings were applied to the possible chemistry of fullerene cations in the interstellar medium with a focus on multiply charged fullerene ion formation and the intervention of fullerene cations in fullerene derivatization and molecular synthesis, with a view to their possible future detection. This article is part of the themed issue ‘Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene’. PMID:27501972

Synthesis of a water-soluble fullerene [C60] under ultrasonication.

PubMed

Ko, Weon-Bae; Heo, Jae-Young; Nam, Jae-Heon; Lee, Kyu-Bong

2004-03-01

A water-soluble fullerene [C60] is prepared with fullerene [C60] and a mixture of strong inorganic acids at the ratio (v/v) of 3:1 under ultrasonic condition at 25-43 degrees C. The MALDI-TOF MS and 13C-NMR spectra confirmed that the product of a water-soluble fullerene compound was C60.

Transparent Conductive Nanofiber Paper for Foldable Solar Cells

PubMed Central

Nogi, Masaya; Karakawa, Makoto; Komoda, Natsuki; Yagyu, Hitomi; Nge, Thi Thi

2015-01-01

Optically transparent nanofiber paper containing silver nanowires showed high electrical conductivity and maintained the high transparency, and low weight of the original transparent nanofiber paper. We demonstrated some procedures of optically transparent and electrically conductive cellulose nanofiber paper for lightweight and portable electronic devices. The nanofiber paper enhanced high conductivity without any post treatments such as heating or mechanical pressing, when cellulose nanofiber dispersions were dropped on a silver nanowire thin layer. The transparent conductive nanofiber paper showed high electrical durability in repeated folding tests, due to dual advantages of the hydrophilic affinity between cellulose and silver nanowires, and the entanglement between cellulose nanofibers and silver nanowires. Their optical transparency and electrical conductivity were as high as those of ITO glass. Therefore, using this conductive transparent paper, organic solar cells were produced that achieved a power conversion of 3.2%, which was as high as that of ITO-based solar cells. PMID:26607742

Thermal conductivity of electrospun polyethylene nanofibers.

PubMed

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.

Nanotribological performance of fullerene-like carbon nitride films

NASA Astrophysics Data System (ADS)

Flores-Ruiz, Francisco Javier; Enriquez-Flores, Christian Ivan; Chiñas-Castillo, Fernando; Espinoza-Beltrán, Francisco Javier

2014-09-01

Fullerene-like carbon nitride films exhibit high elastic modulus and low friction coefficient. In this study, thin CNx films were deposited on silicon substrate by DC magnetron sputtering and the tribological behavior at nanoscale was evaluated using an atomic force microscope. Results show that CNx films with fullerene-like structure have a friction coefficient (CoF ∼ 0.009-0.022) that is lower than amorphous CNx films (CoF ∼ 0.028-0.032). Analysis of specimens characterized by X-ray photoelectron spectroscopy shows that films with fullerene-like structure have a higher number of sp3 CN bonds and exhibit the best mechanical properties with high values of elastic modulus (E > 180 GPa) and hardness (H > 20 GPa). The elastic recovery determined on specimens with a fullerene-like CNx structure was of 95% while specimens of amorphous CNx structure had only 75% elastic recovery.

Fabrication of nanofiber mats from electrospinning of functionalized polymers

NASA Astrophysics Data System (ADS)

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.

Synthesis and photocatalytic activity of electrospun niobium oxide nanofibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qi, Shishun; Zuo, Ruzhong, E-mail: piezolab@hfut.edu.cn; Liu, Yi

2013-03-15

Graphical abstract: Different morphologies are obtained for the electrospun niobium oxide nanofibers with different phase structures. The nanofibers of the two phase structures present different band gap value and the light absorption. Hexagonal phase nanofibers show better photocatalytic activity compared with the orthorhombic nanofibers. Highlights: ► Niobium oxide nanofibers of two phase structures were fabricated by electrospinning. ► Photocatalytic properties of the niobium oxide nanofibers were first explored. ► Nanofibers of different phase structures showed different photocatalytic activities. ► Reasons for the differences in the photocatalysis were carefully discussed. - Abstract: Niobium oxide (Nb{sub 2}O{sub 5}) nanofibers have been synthesizedmore » by sol–gel based electrospinning technique. Pure hexagonal phase (H-Nb{sub 2}O{sub 5}) and orthorhombic phase (O-Nb{sub 2}O{sub 5}) nanofibers were obtained by thermally annealing the electrospun Nb{sub 2}O{sub 5}/polyvinylpyrrolidone composite fibers in air at 500 °C and 700 °C, respectively. The fibers were characterized using the X-ray diffraction, scanning electron microscopy, specific surface area analyzer and UV–vis diffuse reflectance spectroscopy. Photocatalytic activities of the obtained nanofibers were evaluated depending on the degradation of methyl orange. The results indicate that the heat-treatment temperature, the crystalline structure and the morphology affected the physical and chemical properties of the as-prepared Nb{sub 2}O{sub 5} nanofibers. The H-Nb{sub 2}O{sub 5} nanofibers obtained at lower temperature showed better potential for the application as a promising photocatalyst.« less

‘Horror vacui’ or topological in-out isomerism in perhydrogenated fullerenes: C60H60 and monoalkylated perhydrogenated fullerenes

NASA Astrophysics Data System (ADS)

Dodziuk, Helena; Nowinski, Krzysztof

1996-02-01

In endohedral chemistry, one of the exciting prospects offered by the cage-like structure of fullerenes, several aspects of the calculations on in-out isomerism of perhydrogenated fullerene and their consequences went unnoticed, e.g. the topological character of the isomerism, the instability of C 60F 60, which was thought to revolutionize industry as an ideal lubricant, as well as the possibility of in-out isomerism in alkylated fulleranes. Molecular mechanics calculations indicate that for smaller alkyl groups the 'in' isomer is significantly more stable extending the possibility of endohedral fullerene chemistry. C 60H 60 and its derivatives can be considered as examples of a manifestation of the ancient 'horror vacui' concept.

Fullerene surfactants and their use in polymer solar cells

DOEpatents

Jen, Kwan-Yue; Yip, Hin-Lap; Li, Chang-Zhi

2015-12-15

Fullerene surfactant compounds useful as interfacial layer in polymer solar cells to enhance solar cell efficiency. Polymer solar cell including a fullerene surfactant-containing interfacial layer intermediate cathode and active layer.

Nanofiber scaffold gradients for interfacial tissue engineering.

PubMed

Ramalingam, Murugan; Young, Marian F; Thomas, Vinoy; Sun, Limin; Chow, Laurence C; Tison, Christopher K; Chatterjee, Kaushik; Miles, William C; Simon, Carl G

2013-02-01

We have designed a 2-spinnerette device that can directly electrospin nanofiber scaffolds containing a gradient in composition that can be used to engineer interfacial tissues such as ligament and tendon. Two types of nanofibers are simultaneously electrospun in an overlapping pattern to create a nonwoven mat of nanofibers containing a composition gradient. The approach is an advance over previous methods due to its versatility - gradients can be formed from any materials that can be electrospun. A dye was used to characterize the 2-spinnerette approach and applicability to tissue engineering was demonstrated by fabricating nanofibers with gradients in amorphous calcium phosphate nanoparticles (nACP). Adhesion and proliferation of osteogenic cells (MC3T3-E1 murine pre-osteoblasts) on gradients was enhanced on the regions of the gradients that contained higher nACP content yielding a graded osteoblast response. Since increases in soluble calcium and phosphate ions stimulate osteoblast function, we measured their release and observed significant release from nanofibers containing nACP. The nanofiber-nACP gradients fabricated herein can be applied to generate tissues with osteoblast gradients such as ligaments or tendons. In conclusion, these results introduce a versatile approach for fabricating nanofiber gradients that can have application for engineering graded tissues.

One-pot synthesis of h-BN fullerenes usinsg a graphene oxide template

NASA Astrophysics Data System (ADS)

Kim, Sang Sub; Khai, Tran Van; Kwon, Yong Jung; Katoch, Akash; Wu, Ping; Kim, Hyoun Woo

2015-09-01

Hexagonal-boron nitride ( h-BN) fullerenes were synthesized from a graphene oxide (GO) template by simultaneously heating the GO and B2O3 in the presence of NH3 gas. Transmission electron microscopy (TEM) observations revealed that a considerable amount of product had a fullerene-like nanostructure. Typical BN fullerenes have a polyhedral shape, being hollow nanocages. Lattice-resolved TEM and X-ray diffraction consistently demonstrated the formation of h-BN fullerenes. The FTIR spectrum exhibited absorption bands at approximately 800 and 1378 cm-1, which were related to the h-BN structure. The Raman spectra exhibited peaks at 1368 and 1399 cm-1, which can be related to BN sheets and BN fullerenes, respectively. The photoluminescence spectrum of the h-BN fullerenes taken at 8 K exhibited intense white-light emission. To reveal the origin of the broad emission band, which could be a superimposition of several peaks, we used a deconvolution procedure based on Gaussian functions. We proposed a growth mechanism of the h-BN fullerenes and verified it with a thermodynamic calculation. This work provides a cost-effective approach to synthesize fullerene-type boron nitride on a production scale.

Centrifugal spinning: A novel approach to fabricate porous carbon fibers as binder-free electrodes for electric double-layer capacitors

NASA Astrophysics Data System (ADS)

Lu, Yao; Fu, Kun; Zhang, Shu; Li, Ying; Chen, Chen; Zhu, Jiadeng; Yanilmaz, Meltem; Dirican, Mahmut; Zhang, Xiangwu

2015-01-01

Carbon nanofibers (CNFs), among various carbonaceous candidates for electric double-layer capacitor (EDLC) electrodes, draw extensive attention because their one-dimensional architecture offers both shortened electron pathways and high ion-accessible sites. Creating porous structures on CNFs yields larger surface area and enhanced capacitive performance. Herein, porous carbon nanofibers (PCNFs) were synthesized via centrifugal spinning of polyacrylonitrile (PAN)/poly(methyl methacrylate) (PMMA) solutions combined with thermal treatment and were used as binder-free EDLC electrodes. Three precursor fibers with PAN/PMMA weight ratios of 9/1, 7/3 and 5/5 were prepared and carbonized at 700, 800, and 900 °C, respectively. The highest specific capacitance obtained was 144 F g-1 at 0.1 A g-1 with a rate capability of 74% from 0.1 to 2 A g-1 by PCNFs prepared with PAN/PMMA weight ratio of 7/3 at 900 °C. These PCNFs also showed stable cycling performance. The present work demonstrates that PCNFs are promising EDLC electrode candidate and centrifugal spinning offers a simple, cost-effective strategy to produce PCNFs.

Enhanced electrochemical properties of SnO2-graphene-carbon nanofibers tuned by phosphoric acid for potassium storage.

PubMed

Huang, Zhao; Chen, Zhi; Ding, Shuangshuang; Chen, Changmiao; Zhang, Ming

2018-06-21

Potassium-ion batteries (KIBs) are considered as attractive alternatives to commercial lithium-ion batteries (LIBs). However, the lack of suitable electrodes to host large K+ for rapid as well as reversible insertion/extraction hinders the developments of KIBs. As an attempt, the phosphoric acid doped SnO2-graphene-carbon (P-SGC) nanofibers synthesized with a facile electrospinning method are introduced and applied as anode materials for KIBs. The P-SGC anodes present a reversible capacity of 285.9 mAh g-1 over 60 cycles at the current density of 100 mA g-1, and the high rate capacity of 208.53 mAh g-1 at 1 A g-1 as well. Emphasis is placed on enhancing the electrochemical properties of the SGC nanofibers by phosphoric acid modification through more active sites and higher electrical conductivity, accounting for improved K+ diffusion kinetics. Meanwhile, the coated carbon matrix and dispersive graphene buffer the structural changes and protect the active materials from destruction, leading to the good structural stability. With the presented results, these P-SGC nanofibers show attractive potential for future energy storage application of KIBs. © 2018 IOP Publishing Ltd.

Stable Au–C bonds to the substrate for fullerene-based nanostructures

PubMed Central

Chutora, Taras; Redondo, Jesús; de la Torre, Bruno; Švec, Martin

2017-01-01

We report on the formation of fullerene-derived nanostructures on Au(111) at room temperature and under UHV conditions. After low-energy ion sputtering of fullerene films deposited on Au(111), bright spots appear at the herringbone corner sites when measured using a scanning tunneling microscope. These features are stable at room temperature against diffusion on the surface. We carry out DFT calculations of fullerene molecules having one missing carbon atom to simulate the vacancies in the molecules resulting from the sputtering process. These modified fullerenes have an adsorption energy on the Au(111) surface that is 1.6 eV higher than that of C60 molecules. This increased binding energy arises from the saturation by the Au surface of the bonds around the molecular vacancy defect. We therefore interpret the observed features as adsorbed fullerene-derived molecules with C vacancies. This provides a pathway for the formation of fullerene-based nanostructures on Au at room temperature. PMID:28685108

Wood-Derived Ultrathin Carbon Nanofiber Aerogels.

PubMed

Li, Si-Cheng; Hu, Bi-Cheng; Ding, Yan-Wei; Liang, Hai-Wei; Li, Chao; Yu, Zi-You; Wu, Zhen-Yu; Chen, Wen-Shuai; Yu, Shu-Hong

2018-06-11

Carbon aerogels with 3D networks of interconnected nanometer-sized particles exhibit fascinating physical properties and show great application potential. Efficient and sustainable methods are required to produce high-performance carbon aerogels on a large scale to boost their practical applications. An economical and sustainable method is now developed for the synthesis of ultrathin carbon nanofiber (CNF) aerogels from the wood-based nanofibrillated cellulose (NFC) aerogels via a catalytic pyrolysis process, which guarantees high carbon residual and well maintenance of the nanofibrous morphology during thermal decomposition of the NFC aerogels. The wood-derived CNF aerogels exhibit excellent electrical conductivity, a large surface area, and potential as a binder-free electrode material for supercapacitors. The results suggest great promise in developing new families of carbon aerogels based on the controlled pyrolysis of economical and sustainable nanostructured precursors. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electronic properties of Bilayer Fullerene onions

NASA Astrophysics Data System (ADS)

Pincak, R.; Shunaev, V. V.; Smotlacha, J.; Slepchenkov, M. M.; Glukhova, O. E.

2017-10-01

The HOMO-LUMO gaps of the bilayer fullerene onions were investigated. For this purpose, the HOMO and LUMO energies were calculated for the isolated fullerenes using the parametrization of the tight binding method with the Harrison-Goodwin modification. Next, the difference of the Fermi levels of the outer and inner shell was calculated by considering the hybridization of the orbitals on the base of the geometric parameters. The results were obtained by the combination of these calculations.

Hybridizing CNT/PMMA/PVDF towards high-performance piezoelectric nanofibers

NASA Astrophysics Data System (ADS)

Fang, K. Y.; Fang, F.; Wang, S. W.; Yang, W.; Sun, W.; Li, J. F.

2018-07-01

Piezoelectric nanofibers are of great importance in their potential applications as smart fibers and textiles to bring changes to daily lives. By employing the technique of electrospinning, polyvinylidene fluoride (PVDF) nanofibers modified with polymethyl methacrylate (PMMA) and single-wall carbon nanotubes (CNTs) (referred to as CNT/PMMA/PVDF) are prepared. The electric field induced displacement of the as-prepared nanofibers is characterized by piezoresponse force microscopy. Compared with the pure PVDF nanofibers, the CNT/PMMA/PVDF nanofibers exhibit a great enhancement of about 196% for the electric field induced displacement, while increments of about 104% and 78% are obtained for the PMMA/PVDF and CNT/PVDF nanofibers, respectively. A structural analysis indicates that the hydrogen bonding between the O atom in the carbonyl group of PMMA and the hydrogen atom in the CH2 groups of PVDF, the promotion of the nucleation of crystallites by CNTs, work synergistically to produce the high electroactive response of the CNT/PMMA/PVDF nanofibers. Based on the high-performance nanofibers, a prototype of a flexible nanofiber generator is fabricated, which exhibits a typical electrical output of 3.11 V upon a repeated impact-release loading at a frequency of 50 Hz.

Search for fullerenes in stone meteorites

NASA Astrophysics Data System (ADS)

Oester, M. Y.; Kuechl, D.; Sipiera, P. P.; Welch, C. J.

1994-07-01

The possibility of identifying fullerenes in stony meteorites became apparent from a paper given by Radicati de Brozolo. In this paper it was reported that fullerenes were present in the debris resulting from a collision between a micrometeoroid and an orbiting satellite. This fact generated sufficient curiosity to initiate a search for the presence of fullerenes in various stone meteorites. In the present study seven ordinary chondrites (al-Ghanim L6 (find), Dimmitt H4 (find), Lazbuddie LL5 (find), New Concord H5 (fall), Silverton H4 (find), Springlake L6 (find), and Umbarger L3/6 (find)). Four carbonaceous chondrites (ALH 83100 C2 (find), ALH 83108 C30 (find), Allende CV3 (fall), and Murchison CM2 (fall), and one achondrite (Monticello How (find)) were analyzed for the presence of fullerenes. The analytical procedure employed was as follows: 100 mg of meteorite was ground up with a mortar and pestle; 10 mL of toluene was then added and the mixture was refluxed for 90 min; this mixture was then filtered through a short column of silica; a 50 microliter sample was then analyzed by high pressure liquid chromatography (HPLC) using a Buckyclutcher I column with a mobile phase consisting of equal volumes of toluene and hexane at a flow rate of 1.00 mg per minute, with detection at 330 and 600 nm. Three of the meteorites, Allende, Murchison, and al-Ghanim, gave HPLC traces containing peaks with similar retention times to the HPLC trace of an authentic fullerene C60. However, further analysis using an HPLC instrument equipped with a diode-array detector failed to confirm any of the substances detected in the three meteorites as C60. Additional analyses will be conducted to identify what the HPLC traces actually represent.

Characterization and morphology of prepared titanium dioxide nanofibers by electrospinning.

PubMed

Park, Ju-Young; Lee, In-Hwa

2010-05-01

Dispersed titanium dioxide in polymer nanofibers were prepared by sol-gel processing and electrospinning techniques using titanium isopropoxide (TiP)/polyvinylpyrrolidone (PVP) solution. The prepared titanium dioxide nanofibers were characterized by FE-SEM, TEM, XRD, and FT-IR. Pure titanium dioxide nanofibers were obtained from calcination of inorganic-organic composite fiber. The diameter of titanium oxide nanofibers were in the range of 70 nm to 150 nm. Prepared titanium dioxide nanofibers show rough surface and rather small diameter compare with TiP/PVP composite nanofibers. After calcined at 500 degrees C, TiO2 nanofibers convert into anatase and rutile mixed phased from amorphous structure. Calcination of these composite fibers above 600 degrees C resulted in pure rutile TiO2 nanofibers.

Storage of nuclear materials by encapsulation in fullerenes

DOEpatents

Coppa, Nicholas V.

1994-01-01

A method of encapsulating radioactive materials inside fullerenes for stable long-term storage. Fullerenes provide a safe and efficient means of disposing of nuclear waste which is extremely stable with respect to the environment. After encapsulation, a radioactive ion is essentially chemically isolated from its external environment.

Transport of Fullerene Nanoparticles in Saturated Porous Media

EPA Science Inventory

The high strength, electrical conductivity, and electron affinity of fullerenes has lead to their utilization in fuel cells and drug-delivery devices, as well as in cosmetics and other applications. Though C60 fullerene is very insoluble in water, studies have shown that C60 ful...

Dynamic reassembly of peptide RADA16 nanofiber scaffold

NASA Astrophysics Data System (ADS)

Yokoi, Hidenori; Kinoshita, Takatoshi; Zhang, Shuguang

2005-06-01

Nanofiber structures of some peptides and proteins as biological materials have been studied extensively, but their molecular mechanism of self-assembly and reassembly still remains unclear. We report here the reassembly of an ionic self-complementary peptide RADARADARADARADA (RADA16-I) that forms a well defined nanofiber scaffold. The 16-residue peptide forms stable -sheet structure and undergoes molecular self-assembly into nanofibers and eventually a scaffold hydrogel consisting of >99.5% water. In this study, the nanofiber scaffold was sonicated into smaller fragments. Circular dichroism, atomic force microscopy, and rheology were used to follow the kinetics of the reassembly. These sonicated fragments not only quickly reassemble into nanofibers that were indistinguishable from the original material, but their reassembly also correlated with the rheological analyses showing an increase of scaffold rigidity as a function of nanofiber length. The disassembly and reassembly processes were repeated four times and, each time, the reassembly reached the original length. We proposed a plausible sliding diffusion model to interpret the reassembly involving complementary nanofiber cohesive ends. This reassembly process is important for fabrication of new scaffolds for 3D cell culture, tissue repair, and regenerative medicine. atomic force microscopy | circular dichroism | dynamic behaviors | ionic self-complementary peptides | nanofiber hydrogels

Magnetorheology of dimorphic magnetorheological fluids based on nanofibers

NASA Astrophysics Data System (ADS)

Bombard, Antonio J. F.; Gonçalves, Flavia R.; Morillas, Jose R.; de Vicente, Juan

2014-12-01

We report a systematic experimental investigation on the use of nanofibers to enhance the magnetorheological (MR) effect in conventional (microsphere-based) MR fluids formulated in polyalphaolefin oil/1-octanol. Two kinds of nanofibers are employed that have very similar morphology but very different magnetic properties. On the one hand we use non-magnetic goethite nanofibers. On the other hand we employ magnetic chromium dioxide nanofibers. For appropriate concentrations the on-state relative yield stress increases up to 80% when incorporating the nanofibers in the formulation. A similar yield stress enhancement is found for both nanofibers investigated (magnetic and non-magnetic) suggesting that the main factor behind this MR enhancement is the particle shape anisotropy. The relative yield stresses obtained by partial substitution of carbonyl iron particles with nanofibers are significantly larger than those measured in previous works on MR fluids formulated by partial substitution with non-magnetic micronsized spherical particles. We also demonstrate that these dimorphic MR fluids also exhibit remarkably larger long-term sedimentation stability while keeping the same penetration and redispersibility characteristics.

Quantum transport through single and multilayer icosahedral fullerenes

NASA Astrophysics Data System (ADS)

Lovey, Daniel A.; Romero, Rodolfo H.

2013-10-01

We use a tight-binding Hamiltonian and Green functions methods to calculate the quantum transmission through single-wall fullerenes and bilayered and trilayered onions of icosahedral symmetry attached to metallic leads. The electronic structure of the onion-like fullerenes takes into account the curvature and finite size of the fullerenes layers as well as the strength of the intershell interactions depending on to the number of interacting atom pairs belonging to adjacent shells. Misalignment of the symmetry axes of the concentric iscosahedral shells produces breaking of the level degeneracies of the individual shells, giving rise some narrow quasi-continuum bands instead of the localized discrete peaks of the individual fullerenes. As a result, the transmission function for non symmetrical onions is rapidly varying functions of the Fermi energy. Furthermore, we found that most of the features of the transmission through the onions are due to the electronic structure of the outer shell with additional Fano-like antiresonances arising from coupling with or between the inner shells.

Quantitative Analysis of Fullerene Nanomaterials in Environmental Systems: A Critical Review

PubMed Central

Isaacson, Carl W.; Kleber, Markus; Field, Jennifer A.

2009-01-01

The increasing production and use of fullerene nanomaterials has led to calls for more information regarding the potential impacts that releases of these materials may have on human and environmental health. Fullerene nanomaterials, which are comprised of both fullerenes and surface-functionalized fullerenes, are used in electronic, optic, medical and cosmetic applications. Measuring fullerene nanomaterial concentrations in natural environments is difficult because they exhibit a duality of physical and chemical characteristics as they transition from hydrophobic to polar forms upon exposure to water. In aqueous environments, this is expressed as their tendency to initially (i) self assemble into aggregates of appreciable size and hydrophobicity, and subsequently (ii) interact with the surrounding water molecules and other chemical constituents in natural environments thereby acquiring negative surface charge. Fullerene nanomaterials may therefore deceive the application of any single analytical method that is applied with the assumption that fullerenes have but one defining characteristic (e.g., hydrophobicity). [1] We find that analytical procedures are needed to account for the potentially transitory nature of fullerenes in natural environments through the use of approaches that provide chemically-explicit information including molecular weight and the number and identity of surface functional groups. [2] We suggest that sensitive and mass-selective detection, such as that offered by mass spectrometry when combined with optimized extraction procedures, offers the greatest potential to achieve this goal. [3] With this review, we show that significant improvements in analytical rigor would result from an increased availability of well characterized authentic standards, reference materials, and isotopically-labeled internal standards. Finally, the benefits of quantitative and validated analytical methods for advancing the knowledge on fullerene occurrence, fate

Electrospinning of ceramic nanofibers

NASA Astrophysics Data System (ADS)

Eick, Benjamin M.

Silicon Carbide (SiC) nanofibers of diameters as low as 20 nm are fabricated. The fibers were produced through the electrostatic spinning of the preceramic poly(carbomethylsilane) with pyrolysis to ceramic. A new technique was used where the preceramic was blended with polystyrene (PS) and, subsequent to electrospinning, was exposed to UV to crosslink the PS and prevent fibers flowing during pyrolysis. Electrospun SiC fibers were characterized by FTIR, TGA-DTA, SEM, TEM, XRD, and SAED. Fibers were shown to be polycrystalline and nanograined with alpha-SiC 15R polytype being dominant, where commercial fiber production methods form beta-SiC 3C. Pyrolysis of the bulk polymer blend to SiC produced alpha-SiC 15R as the dominant polytype with larger grains showing that electrospinning nanofibers affects resultant crystallinity. Fibers produced were shown to have a core-shell structure of an oxide scale that was variable by pyrolysis conditions. Metal oxide powders (chromium oxide, cobalt oxide, iron oxide, silicon oxide, tantalum oxide, titanium oxide, tungsten oxide, vanadium oxide, and zirconium oxide), were converted to metal carbide powders and metal nitride powders by the process of carbothermal reduction (CTR). Synthetic pitch was explored as an alternative to graphite which is a common carbon source for CTR. It was shown via characterization with XRD that pitch performs as well and in some cases better than graphite and is therefore a viable alternative in CTR. Conversion of metal oxide powders with pitch led to conversion of sol-gel based metal oxide nanofibers produced by electrospinning. Pitch was soluble in the solutions xv that were electrospun allowing for intimate contact between the sol-gel and the carbon source for CTR. This method became a two step processing method to produce metal carbide and nitride nanofibers: first electrospin sol-gel based metal oxide nanofibers and subsequently pyrolize them in the manner of CTR to transform them. Results indicate

Calculation of the energy loss for an electron passing near giant fullerenes

NASA Astrophysics Data System (ADS)

Henrard, L.; Lambin, Ph

1996-11-01

We present a theoretical analysis of the electron energy-loss spectra of isolated giant fullerenes. We use a macroscopic dielectric description of spherical onion-like fullerenes and a discrete dipole approximation (DDA) framework for tubular fullerenes. In the DDA model, an anisotropic dynamical polarizability is assigned to each carbon site. We stress the fundamental importance of the hollow character of giant fullerenes in the electron energy-loss resonances.

Rapid fabrication of titania nanofibers by electrospinning

NASA Astrophysics Data System (ADS)

Li, Dan; Xia, Younan

2003-11-01

This paper describes a simple and convenient procedure for fabricating polycrystalline titania nanofibers with controllable diameter and porous structures. By combining sol-gel technique and electrospinning, nanofibers made of poly(vinyl pyrrolidone) (PVP) and amorphous TiO2 were firstly obtained by electrospinning an ethanol solution containing both PVP and titanium tetraisopropoxide under appropriate high voltages. These nanofibers could be subsequently converted to anatase without changing their morphology via calcination in air at 500°C. The average diameter of these ceramic nanofibers could be controlled in the range from 20 to 200 nm by varying a number of parameters such as the voltage, the feeding rate of the precursor solution, the ratio between PVP and titanium tetraisopropoxide, and their concentrations in the alcohol solution. Titanium tetraisopropoxide could be transferred to titania nanofibers with ~100% yield by using this technique.

Antimicrobial Photodynamic Inactivation and Antitumor Photodynamic Therapy with Fullerenes

NASA Astrophysics Data System (ADS)

de Freitas, Lucas F.

2016-04-01

This book provides detailed and current information on using fullerenes (bucky-balls) in photodynamic therapy (PDT), one of the most actively studied applications of photonic science in healthcare. This will serve as a useful source for researchers working in photomedicine and nanomedicine, especially those who are investigating PDT for cancer treatment and infectious disease treatment. The book runs the gamut from an introduction to the history and chemistry of fullerenes and some basic photochemistry, to the application of fullerenes as photosensitizers for cancer and antimicrobial inactivation.

Electrochemical sensing platform based on the highly ordered mesoporous carbon-fullerene system.

PubMed

Zhou, Ming; Guo, Jidong; Guo, Li-ping; Bai, Jing

2008-06-15

In this paper, we report a novel all-carbon two-dimensionally ordered nanocomposite electrode system on the basis of the consideration of host-guest chemistry, which utilizes synergistic interactions between a nanostructured matrix of ordered mesoporous carbon (OMC) and an excellent electron acceptor of nanosized fullerene (C 60) to facilitate heterogeneous electron-transfer processes. The integration of OMC-C 60 by covalent interaction, especially its electrochemical applications for electrocatalysis, has not been explored thus far. Such integration may even appear to be counterintuitive because OMC and C 60 provide opposite electrochemical benefits in terms of facilitating heterogeneous electron-transfer processes. Nevertheless, the present work demonstrates the integration of OMC and C 60 can provide a remarkable synergistic augmentation of the current. To illuminate the concept, eight kinds of inorganic and organic electroactive compounds were employed to study the electrochemical response at an OMC-C 60 modified glassy carbon (OMC-C 60/GC) electrode for the first time, which shows more favorable electron-transfer kinetics than OMC/GC, carbon nanotube modified GC, C 60/GC, and GC electrodes. Such electrocatalytic behavior at OMC-C 60/GC electrode could be attributed to the unique physicochemical properties of OMC and C 60, especially the unusual host-guest synergy of OMC-C 60, which induced a substantial decrease in the overvoltage for NADH oxidation compared with GC electrode. The ability of OMC-C 60 to promote electron transfer not only suggests a new platform for the development of dehydrogenase-based bioelectrochemical devices but also indicates a potential of OMC-C 60 to be of a wide range of sensing applications because the electrocatalysis of different electroactive compounds at the OMC-C 60/GC electrode in this work should be a good model for constructing a novel and promising electrochemical sensing platform for further electrochemical detection of

Fabrication of nylon/fullerene polymer memory

NASA Astrophysics Data System (ADS)

Jayan, Manuvel; Davis, Rosemary; Karthik, M. P.; Devika, K.; Kumar, G. Vijay; Sriraj, B.; Predeep, P.

2017-06-01

Two terminal Organic memories in passive matrix array form with device structure, Al/Nylon/ (Nylon+C60)/Nylon/ Al are fabricated. The current-voltage measurements showed hysteresis and the devices are thoroughly characterized for write-read-erase-read cycles. The control over the dispersion concentration, capacity of fullerene to readily accept electrons and the constant diameter of fullerene made possible uniform device fabrication with reproducible results. Scanning electron micrographs indicated that the device thickness remained uniform in the range of 19 micrometers.

TiO2/ZnO and ZnO/TiO2 core/shell nanofibers prepared by electrospinning and atomic layer deposition for photocatalysis and gas sensing

NASA Astrophysics Data System (ADS)

Boyadjiev, Stefan I.; Kéri, Orsolya; Bárdos, Péter; Firkala, Tamás; Gáber, Fanni; Nagy, Zsombor K.; Baji, Zsófia; Takács, Máté; Szilágyi, Imre M.

2017-12-01

In the present work, core TiO2 and ZnO oxide nanofibers were prepared by electrospinning, then shell oxide (ZnO, TiO2) layers were deposited on them by atomic layer deposition (ALD). The aim of preparing ZnO and TiO2 nanofibers, as well as ZnO/TiO2 and TiO2/ZnO nanocomposites is to study the interaction between the oxide materials when a pure oxide fiber is covered with thin film of the other oxide, and explore the influence of exchanging the core and shell materials on their photocatalytic and gas sensing properties. The composition, structure and morphology of the pure and composite nanofibers were studied by SEM-EDX, TEM, XRD, FTIR, UV-vis and Raman. The photocatalytic activity of the as-prepared materials was analyzed by UV-vis spectroscopy through decomposing aqueous methyl orange under UV irradiation. The gas sensing of the nanofibers was investigated by detecting 100 ppm NH3 at 150 and 220 °C using interdigital electrode based sensors.

Donor polymer design enables efficient non-fullerene organic solar cells

PubMed Central

Li, Zhengke; Jiang, Kui; Yang, Guofang; Lai, Joshua Yuk Lin; Ma, Tingxuan; Zhao, Jingbo; Ma, Wei; Yan, He

2016-01-01

To achieve efficient organic solar cells, the design of suitable donor–acceptor couples is crucially important. State-of-the-art donor polymers used in fullerene cells may not perform well when they are combined with non-fullerene acceptors, thus new donor polymers need to be developed. Here we report non-fullerene organic solar cells with efficiencies up to 10.9%, enabled by a novel donor polymer that exhibits strong temperature-dependent aggregation but with intentionally reduced polymer crystallinity due to the introduction of a less symmetric monomer unit. Our comparative study shows that an analogue polymer with a C2 symmetric monomer unit yields highly crystalline polymer films but less efficient non-fullerene cells. Based on a monomer with a mirror symmetry, our best donor polymer exhibits reduced crystallinity, yet such a polymer matches better with small molecular acceptors. This study provides important insights to the design of donor polymers for non-fullerene organic solar cells. PMID:27782112

The interactions of high-energy, highly-charged ions with fullerenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ali, R.; Berry, H.G.; Cheng, S.

1996-03-01

In 1985, Robert Curl and Richard Smalley discovered a new form of carbon, the fullerene, C{sub 60}, which consists of 60 carbon atoms in a closed cage resembling a soccer ball. In 1990, Kritschmer et al. were able to make macroscopic quantities of fullerenes. This has generated intense activity to study the properties of fullerenes. One area of research involves collisions between fullerenes and atoms, ions or electrons. In this paper we describe experiments involving interactions between fullerenes and highly charged ions in which the center-of-mass energies exceed those used in other work by several orders of magnitude. The highmore » values of projectile velocity and charge state result in excitation and decay processes differing significantly from those seen in studies 3 at lower energies. Our results are discussed in terms of theoretical models analogous to those used in nuclear physics and this provides an interesting demonstration of the unity of physics.« less

Nanofiber-net-binary structured membranes for highly sensitive detection of trace HCl gas

NASA Astrophysics Data System (ADS)

Wang, Xianfeng; Wang, Jialin; Si, Yang; Ding, Bin; Yu, Jianyong; Sun, Gang; Luo, Wenjing; Zheng, Gang

2012-11-01

This work describes the detection of trace hydrogen chloride (HCl) gas through analyses of the resonance frequency signal from quartz crystal microbalance (QCM) sensors coated with polyaniline (PANI) functionalized polyamide 6 (PA 6) (PANI-PA 6) nanofiber-net-binary (NNB) structured membranes. The PA 6 NNB substrate comprising nanofibers and spider-web-like nano-nets fabricated by a versatile electro-spinning/netting (ESN) process offered an ideal interface for the uniform PANI functionalization and enhanced sensing performance. Benefiting from the large specific surface area, high porosity, and strong adhesive force to the QCM electrode of the PANI-PA 6 NNB membranes, the developed HCl-selective sensors exhibited a rapid response, good reproducibility and stability, and low detection limit (7 ppb) at room temperature. Additionally, the PANI-PA 6 NNB sensing membranes presented visible color changes upon cycled exposure to HCl and ammonia, suggesting their potential application in the development of colorimetric sensors. The PANI-PA 6 NNB coated QCM sensors are considered to be a promising candidate for trace HCl gas detection in practical applications.

Electrospun Nanofibers of Guar Galactomannan for Targeted Drug Delivery

NASA Astrophysics Data System (ADS)

Chu, Hsiao Mei Annie

2011-12-01

Guar galactomannan is a biodegradable polysaccharide used widely in the food industry but also in the cosmetics, pharmaceutical, oil drilling, textile and paper industries. Guar consists of a mannose backbone and galactose side groups that are both susceptible to enzyme degradation, a unique property that can be explored for targeted drug delivery especially since those enzymes are naturally secreted by the microflora in human colon. The present study can be divided into three parts. In the first part, we discuss ways to modify guar to produce nanofibers by electrospinning, a process that involves the application of an electric field to a polymer solution or melt to facilitate production of fibers in the sub-micron range. Nanofibers are currently being explored as the next generation of drug carriers due to its many advantages, none more important than the fact that nanofibers are on a size scale that is a fraction of a hair's width and have large surface-to-volume ratio. The incorporation and controlled release of nano-sized drugs is one way in which nanofibers are being utilized in drug delivery. In the second part of the study, we explore various methods to crosslink guar nanofibers as a means to promote water-resistance in a potential drug carrier. The scope and utility of water-resistant guar nanofibers can only be fully appreciated when subsequent drug release studies are carried out. To that end, the third part of our study focuses on understanding the kinetics and diffusion mechanisms of a model drug, Rhodamine B, through moderately-swelling (crosslinked) hydrogel nanofibers in comparison to rapidly-swelling (non-crosslinked) nanofibers. Along the way, our investigations led us to a novel electrospinning set-up that has a unique collector designed to capture aligned nanofibers. These aligned nanofiber bundles can then be twisted to hold them together like yarn. From a practical standpoint, these yarns are advantageous because they come freely suspended and

Fullerenes and interplanetary dust at the Permian-Triassic boundary.

PubMed

Poreda, Robert J; Becker, Luann

2003-01-01

We recently presented new evidence that an impact occurred approximately 250 million years ago at the Permian-Triassic boundary (PTB), triggering the most severe mass extinction in the history of life on Earth. We used a new extraterrestrial tracer, fullerene, a third carbon carrier of noble gases besides diamond and graphite. By exploiting the unique properties of this molecule to trap noble gases inside of its caged structure (helium, neon, argon), the origin of the fullerenes can be determined. Here, we present new evidence for fullerenes with extraterrestrial noble gases in the PTB at Graphite Peak, Antarctica, similar to PTB fullerenes from Meishan, China and Sasayama, Japan. In addition, we isolated a (3)He-rich magnetic carrier phase in three fractions from the Graphite Peak section. The noble gases in this magnetic fraction were similar to zero-age deep-sea interplanetary dust particles (IDPs) and some magnetic grains isolated from the Cretaceous-Tertiary boundary. The helium and neon isotopic compositions for both the bulk Graphite Peak sediments and an isolated magnetic fraction from the bulk material are consistent with solar-type gases measured in zero-age deep-sea sediments and point to a common source, namely, the flux of IDPs to the Earth's surface. In this instance, the IDP noble gas signature for the bulk sediment can be uniquely decoupled from fullerene, demonstrating that two separate tracers are present (direct flux of IDPs for (3)He vs. giant impact for fullerene).

Electrospinning of nickel oxide nanofibers: Process parameters and morphology control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khalil, Abdullah, E-mail: akhalil@masdar.ac.ae; Hashaikeh, Raed, E-mail: rhashaikeh@masdar.ac.ae

2014-09-15

In the present work, nickel oxide nanofibers with varying morphology (diameter and roughness) were fabricated via electrospinning technique using a precursor composed of nickel acetate and polyvinyl alcohol. It was found that the diameter and surface roughness of individual nickel oxide nanofibers are strongly dependent upon nickel acetate concentration in the precursor. With increasing nickel acetate concentration, the diameter of nanofibers increased and the roughness decreased. An optimum concentration of nickel acetate in the precursor resulted in the formation of smooth and continuous nickel oxide nanofibers whose diameter can be further controlled via electrospinning voltage. Beyond an optimum concentration ofmore » nickel acetate, the resulting nanofibers were found to be ‘flattened’ and ‘wavy’ with occasional cracking across their length. Transmission electron microscopy analysis revealed that the obtained nanofibers are polycrystalline in nature. These nickel oxide nanofibers with varying morphology have potential applications in various engineering domains. - Highlights: • Nickel oxide nanofibers were synthesized via electrospinning. • Fiber diameter and roughness depend on nickel acetate concentration used. • With increasing nickel acetate concentration the roughness of nanofibers decreased. • XRD and TEM revealed a polycrystalline structure of the nanofibers.« less

Photophysical properties of fullerene-dendron-pyropheophorbide supramolecules

NASA Astrophysics Data System (ADS)

Ermilov, E. A.; Al-Omari, S.; Helmreich, M.; Jux, N.; Hirsch, A.; Röder, B.

2004-05-01

Two novel monofullerene-bis(pyropheophorbide a) complexes were synthesized and their photophysical properties were studied by using both steady-state and time-resolved techniques. It was revealed that in the pyropheophorbide a (pyroPheo)-C 60 molecular system (FP1) strong quenching of the first excited singlet state of the pyroPheo and, as result, dramatically decreasing of photosensitized singlet oxygen generation occurs by efficient photoinduced electron transfer to the fullerene molecule with a rate constant of 2.5 × 10 9 s -1. In contrast, the fullerene hexaadduct-bis(pyroPheo) system (FHP1), which possesses five diethyl malonate addends in the remaining octahedral positions, shows a high singlet oxygen quantum yield which is due to the reduced fullerene chromophore which is not a good electron acceptor anymore.

Nanofibers and their applications in tissue engineering

PubMed Central

Vasita, Rajesh; Katti, Dhirendra S

2006-01-01

Developing scaffolds that mimic the architecture of tissue at the nanoscale is one of the major challenges in the field of tissue engineering. The development of nanofibers has greatly enhanced the scope for fabricating scaffolds that can potentially meet this challenge. Currently, there are three techniques available for the synthesis of nanofibers: electrospinning, self-assembly, and phase separation. Of these techniques, electrospinning is the most widely studied technique and has also demonstrated the most promising results in terms of tissue engineering applications. The availability of a wide range of natural and synthetic biomaterials has broadened the scope for development of nanofibrous scaffolds, especially using the electrospinning technique. The three dimensional synthetic biodegradable scaffolds designed using nanofibers serve as an excellent framework for cell adhesion, proliferation, and differentiation. Therefore, nanofibers, irrespective of their method of synthesis, have been used as scaffolds for musculoskeletal tissue engineering (including bone, cartilage, ligament, and skeletal muscle), skin tissue engineering, vascular tissue engineering, neural tissue engineering, and as carriers for the controlled delivery of drugs, proteins, and DNA. This review summarizes the currently available techniques for nanofiber synthesis and discusses the use of nanofibers in tissue engineering and drug delivery applications. PMID:17722259

Investigation of needleless electrospun PAN nanofiber mats

NASA Astrophysics Data System (ADS)

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.

Spatiotemporal Oxygen Sensing Using Dual Emissive Boron Dye–Polylactide Nanofibers

PubMed Central

2015-01-01

Oxygenation in tissue scaffolds continues to be a limiting factor in regenerative medicine despite efforts to induce neovascularization or to use oxygen-generating materials. Unfortunately, many established methods to measure oxygen concentration, such as using electrodes, require mechanical disturbance of the tissue structure. To address the need for scaffold-based oxygen concentration monitoring, a single-component, self-referenced oxygen sensor was made into nanofibers. Electrospinning process parameters were tuned to produce a biomaterial scaffold with specific morphological features. The ratio of an oxygen sensitive phosphorescence signal to an oxygen insensitive fluorescence signal was calculated at each image pixel to determine an oxygenation value. A single component boron dye–polymer conjugate was chosen for additional investigation due to improved resistance to degradation in aqueous media compared to a boron dye polymer blend. Standardization curves show that in fully supplemented media, the fibers are responsive to dissolved oxygen concentrations less than 15 ppm. Spatial (millimeters) and temporal (minutes) ratiometric gradients were observed in vitro radiating outward from the center of a dense adherent cell grouping on scaffolds. Sensor activation in ischemia and cell transplant models in vivo show oxygenation decreases on the scale of minutes. The nanofiber construct offers a robust approach to biomaterial scaffold oxygen sensing. PMID:25426706

The quest for inorganic fullerenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pietsch, Susanne; Dollinger, Andreas; Strobel, Christoph H.

2015-10-02

Experimental results of the search for inorganic fullerenes are presented. Mo nS m - and W nS m - clusters are generated with a pulsed arc cluster ion source equipped with an annealing stage. This is known to enhance fullerene formation in the case of carbon. Analogous to carbon, the mass spectra of the metal chalcogenide clusters produced in this way exhibit a bimodal structure. Moreover, the species in the first maximum at low mass are known to be platelets. The structure of the species in the second maximum is studied by anion photoelectron spectroscopy, scanning transmission electron microscopy,more » and scanning tunneling microcopy. All experimental results indicate a two-dimensional structure of these species and disagree with a three-dimensional fullerene-like geometry. A possible explanation for this preference of two-dimensional structures is the ability of a two-element material to saturate the dangling bonds at the edges of a platelet by excess atoms of one element. A platelet consisting of a single element only cannot do this. Likewise, graphite and boron might be the only materials forming nano-spheres because they are the only single element materials assuming two-dimensional structures.« less

The quest for inorganic fullerenes

NASA Astrophysics Data System (ADS)

Pietsch, Susanne; Dollinger, Andreas; Strobel, Christoph H.; Park, Eun Ji; Ganteför, Gerd; Seo, Hyun Ook; Kim, Young Dok; Idrobo, Juan-Carlos; Pennycook, Stephen J.

2015-10-01

Experimental results of the search for inorganic fullerenes are presented. MonSm- and WnSm- clusters are generated with a pulsed arc cluster ion source equipped with an annealing stage. This is known to enhance fullerene formation in the case of carbon. Analogous to carbon, the mass spectra of the metal chalcogenide clusters produced in this way exhibit a bimodal structure. The species in the first maximum at low mass are known to be platelets. Here, the structure of the species in the second maximum is studied by anion photoelectron spectroscopy, scanning transmission electron microscopy, and scanning tunneling microcopy. All experimental results indicate a two-dimensional structure of these species and disagree with a three-dimensional fullerene-like geometry. A possible explanation for this preference of two-dimensional structures is the ability of a two-element material to saturate the dangling bonds at the edges of a platelet by excess atoms of one element. A platelet consisting of a single element only cannot do this. Accordingly, graphite and boron might be the only materials forming nano-spheres because they are the only single element materials assuming two-dimensional structures.

Synthesis of fullerene@gold core-shell nanostructures.

PubMed

Ren, Yupeng; Paira, Priyankar; Nayak, Tapas Ranjan; Ang, Wee Han; Pastorin, Giorgia

2011-07-21

A "direct encapsulation" method was developed for the synthesis of highly stable water-soluble fullerene@gold core-shell nanostructures, with gold nanoshells showing either closed or porous morphology. This gold nano-shell coating formed a "nano-oven", capable of decomposing encapsulated fullerene molecules rapidly when irradiated by laser. We envisaged this being a useful tool for chemical reactions as well as a novel scaffold for nano-material synthesis.

Production of Conductive PEDOT-Coated PVA-GO Composite Nanofibers

NASA Astrophysics Data System (ADS)

Zubair, Nur Afifah; Rahman, Norizah Abdul; Lim, Hong Ngee; Sulaiman, Yusran

2017-02-01

Electrically conductive nanofiber is well known as an excellent nanostructured material for its outstanding performances. In this work, poly(3,4-ethylenedioxythiophene) (PEDOT)-coated polyvinyl alcohol-graphene oxide (PVA-GO)-conducting nanofibers were fabricated via a combined method using electrospinning and electropolymerization techniques. During electrospinning, the concentration of PVA-GO solution and the applied voltage were deliberately altered in order to determine the optimized electrospinning conditions. The optimized parameters obtained were 0.1 mg/mL of GO concentration with electrospinning voltage of 15 kV, which displayed smooth nanofibrous morphology and smaller diameter distribution. The electrospun PVA-GO nanofiber mats were further modified by coating with the conjugated polymer, PEDOT, using electropolymerization technique which is a facile approach for coating the nanofibers. SEM images of the obtained nanofibers indicated that cauliflower-like structures of PEDOT were successfully grown on the surface of the electrospun nanofibers during the potentiostatic mode of the electropolymerization process. The conductive nature of PEDOT coating strongly depends on the different electropolymerization parameters, resulting in good conductivity of PEDOT-coated nanofibers. The optimum electropolymerization of PEDOT was at a potential of 1.2 V in 5 min. The electrochemical measurements demonstrated that the fabricated PVA-GO/PEDOT composite nanofiber could enhance the current response and reduce the charge transfer resistance of the nanofiber.

Nanofibers: New Insights for Drug Delivery and Tissue Engineering.

PubMed

Haidar, Mohammad Karim; Eroglu, Hakan

2017-01-01

Nanofibers became one of the major research areas for drug delivery and tissue engineering applications in the last decade. Depending on the simplicity of the preparation method and high drug loading capacity, nanofibers provide many advantages for therapeutic perspectives. In addition, combined systems such as embedding nanoparticles into the nanofiber structures provide a second option for delivery of dual active ingredients in the same formulation. The release rate of the active ingredients can also be modified easily by the formulation parameters depending on the desired release time for treatment. Nanofibers systems are used for the delivery of antibiotics, anticancer drugs, analgesics, hemostatic agents and various proteins for tissue engineering purposes. In addition, various applications such as medical device coating also provide new insights for the clinical use of nanofibers. The most commonly used technique for preparation of nanofibers is the electrospinning, which provides feasibility background for scale up process from laboratory to the industrial applications. The main boundary for nanofibers is the limitations for systemic route. Nanofibers are mainly designed for the delivery of active ingredients for local purposes. Regardless of the therapeutic aim, nanofibers are also perfect 3 dimensional structures that are suitable for tissue regeneration. They provide matrix structure for cell regeneration especially in applications for wound healing. This review is mainly focused on the recent advances on the preparation of nanofibers, applications for drug delivery, tissue engineering and wound healing purposes. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Fullerene C60 coated silicon nanowires as anode materials for lithium secondary batteries.

PubMed

Arie, Arenst Andreas; Lee, Joong Kee

2012-04-01

A Fullerene C60 film was introduced as a coating layer for silicon nanowires (Si NWs) by a plasma assisted thermal evaporation technique. The morphology and structural characteristics of the materials were studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). SEM observations showed that the shape of the nanowire structure was maintained after the C60 coating and the XPS analysis confirmed the presence of the carbon coating layer. The electrochemical characteristics of C60 coated Si NWs as anode materials were examined by charge-discharge tests and electrochemical impedance measurements. With the C60 film coating, Si NW electrodes exhibited a higher initial coulombic efficiency of 77% and a higher specific capacity of 2020 mA h g(-1) after the 30th cycle at a current density of 100 microA cm(-2) with cut-off voltage between 0-1.5 V. These improved electrochemical characteristics are attributed to the presence of the C60 coating layer which suppresses side reaction with the electrolyte and maintains the structural integrity of the Si NW electrodes during cycle tests.

Observation of fullerenes (C60-C70) associated with LDEF crater number 31

NASA Technical Reports Server (NTRS)

Radicatidibrozolo, Filippo; Fleming, R. H.; Bunch, T. E.

1992-01-01

The presence of fullerenes in and around the LDEF crater number 31 is reported. This crater has a high C level associated with it, and is interpreted as having been produced by the impact of a C-rich micrometeoroid. Fullerenes are large 3-D C structures, among which the species C sub 60 (MW 720) and C sub 70 (MW 840) are preeminent. Fullerenes have several UV absorption bands, hence fullerenes should be detectable using UV laser ionization time-of-flight mass spectrometry. We use a LIMA-2A instrument with pulsed UV laser (266 nm) to search for high mass C species associated with LDEF crater number 31. The mass range was 0 to 1200 amu. Low ablating laser power levels were used (less than or = 5 x 10 exp 7 W/sq. cm); 200 mass spectra were acquired and summed. We observed high mass signals near m/z 720, exhibiting 24 amu separation, which is characteristic of fullerenes. Alkali ion signals were also observed. Little or no C clusters of intermediate mass were observed. We interpret the signals around m/z 720 as fullerenes, mainly C sub 60+ with lower levels of C sub 70+. We propose that the mechanism that produces these signals is resonant multiphoton ionization (REMPI). This selective mechanism explains why low mass C cluster ions are not observed along with the fullerenes, since they have much higher ionization potentials. This finding is unexpected, since up to now the search for fullerenes in extraterrestrial materials has not been successful. We conclude that the fullerenes became associated with crater number 31 in space. Two alternative (and exciting) scenarios are being considered at this time: either the fullerenes were carried by the C-rich projectile that formed crater number 31, or the fullerenes formed upon impact with the LDEF. We show the results of experiments at the ARC Vertical Gun Facility, which may establish some constraints on the origin of the fullerenes.

Beta-glucan-loaded nanofiber dressing improves wound healing in diabetic mice.

PubMed

Grip, Jostein; Engstad, Rolf Einar; Skjæveland, Ingrid; Škalko-Basnet, Nataša; Isaksson, Johan; Basnet, Purusotam; Holsæter, Ann Mari

2018-06-01

The increased prevalence of chronic wounds requires novel treatment options. The aim of this study was to develop a beta-glucan (βG)-loaded nanofiber wound dressing. Nanofibers were prepared using the needle-free Nanospider™ technology, an electrospinning method which enables the production of nanofibers at an industrial scale. The βG was selected as active ingredient based on its confirmed wound healing potential in both animals and humans. Hydroxypropyl methylcellulose (HPMC) and polyethylene oxide (PEO) were included as copolymers. Rheological profiles of spinning solutions containing HPMC, PEO, βG, ethanol and water, were optimized. The nanofiber formation was confirmed by Field Emission Scanning Electron Microscopy (FE-SEM), and both nanofibers with (βG-nanofibers) or without βG (NoβG-nanofibers) were evaluated by their swelling index and FT-IR spectroscopy. The formulations, active ingredient and excipients were tested for their possible in vitro toxicity in keratinocytes. Finally, the wound healing potential of the nanofibers was tested in externally induced excisional wounds in male diabetic db/db mice. Three different doses of βG-nanofibers and the βG-free, NoβG-nanofibers, were evaluated for their in vivo wound healing efficacy. All nanofiber-treatments provided improved wound healing as compared to the negative control (water). All βG-nanofiber treated groups exhibited significantly improved wound healing as compared to the NoβG-nanofiber treated group, indicating the potential of βG-nanofibers as wound dressing. Copyright © 2018 Elsevier B.V. All rights reserved.

A molecular heterojunction of zinc phthalocyanine and peanut-shaped fullerene polymer: A density functional study

NASA Astrophysics Data System (ADS)

Tanikawa, Kousei; Ohno, Kaoru; Noda, Yusuke; Ono, Shota; Kuwahara, Riichi; Takashima, Akito; Nakaya, Masato; Onoe, Jun

2017-10-01

We have performed first-principles density functional calculations of a molecular heterojunction of a zinc phthalocyanine (ZnPc) molecule and a peanut-shaped fullerene polymer (PSFP) made from several coalesced cross-linked C60 molecules. The PSFP has many isomers and all have both spatially localized (near ZnPc) and metallic conducting levels. Here we consider four typical isomers. From the resulting electronic structure, we discuss the applicability of these isomers to organic photovoltaics (OPV), electrodes, and light harvesting materials. If one of the isomers called T3, which has the largest energy gap, is used together with ZnPc for OPV, this system shows more than 20% energy conversion efficiency.

Dispersion of cellulose nanofibers in biopolymer based nanocomposites

NASA Astrophysics Data System (ADS)

Wang, Bei

The focus of this work was to understand the fundamental dispersion mechanism of cellulose based nanofibers in bionanocomposites. The cellulose nanofibers were extracted from soybean pod and hemp fibers by chemo-mechanical treatments. These are bundles of cellulose nanofibers with a diameter ranging between 50 to 100 nm and lengths of thousands of nanometers which results in very high aspect ratio. In combination with a suitable matrix polymer, cellulose nanofiber networks show considerable potential as an effective reinforcement for high quality specialty applications of bio-based nanocomposites. Cellulose fibrils have a high density of --OH groups on the surface, which have a tendency to form hydrogen bonds with adjacent fibrils, reducing interaction with the surrounding matrix. The use of nanofibers has been mostly restricted to water soluble polymers. This thesis is focused on synthesizing the nanocomposite using a solid phase matrix polypropylene (PP) or polyethylene (PE) by hot compression and poly (vinyl alcohol) (PVA) in an aqueous phase by film casting. The mechanical properties of nanofiber reinforced PVA film demonstrated a 4-5 fold increase in tensile strength, as compared to the untreated fiber-blend-PVA film. It is necessary to reduce the entanglement of the fibrils and improve their dispersion in the matrix by surface modification of fibers without deteriorating their reinforcing capability. Inverse gas chromatography (IGC) was used to explore how various surface treatments would change the dispersion component of surface energy and acid-base character of cellulose nanofibers and the effect of the incorporation of these modified nanofibers into a biopolymer matrix on the properties of their nano-composites. Poly (lactic acid) (PLA) and polyhydroxybutyrate (PHB) based nanocomposites using cellulose nanofibers were prepared by extrusion, injection molding and hot compression. The IGC results indicated that styrene maleic anhydride coated and ethylene

Two-chamber configuration of Bio-Nano electron cyclotron resonance ion source for fullerene modification.

PubMed

Uchida, T; Rácz, R; Muramatsu, M; Kato, Y; Kitagawa, A; Biri, S; Yoshida, Y

2016-02-01

We report on the modification of fullerenes with iron and chlorine using two individually controllable plasmas in the Bio-Nano electron cyclotron resonance ion source (ECRIS). One of the plasmas is composed of fullerene and the other one is composed of iron and chlorine. The online ion beam analysis allows one to investigate the rate of the vapor-phase collisional modification process in the ECRIS, while the offline analyses (e.g., liquid chromatography-mass spectrometry) of the materials deposited on the plasma chamber can give information on the surface-type process. Both analytical methods show the presence of modified fullerenes such as fullerene-chlorine, fullerene-iron, and fullerene-chlorine-iron.

Fullerene nanoparticle in dermatological and cosmetic applications.

PubMed

Mousavi, S Zeinab; Nafisi, Shohreh; Maibach, Howard I

2017-04-01

Nanoparticles are equipped with exceptional properties which make them well suitable for diverse and novel applications. Fullerene is one of the nanomaterials that has valuable applications in the field of biomedicine. It possesses exceptional antioxidant capacity which has made it a promising core ingredient in many dermatological and skin care products. However, fullerene has the potentials to display a range of activities resulting in cell death or dysfunction. This review outlines the achievements made so far by reporting studies that have focused on incorporating fullerene in skin care products and cosmetics and assessed their beneficial effects. We have also documented reports that have assessed toxicity of this novel carbon allotrope toward skin cells and discussed its possible dermal reactions. Aside from pointing out the recent developments, areas that can benefit from further researches are identified. Copyright © 2016 Elsevier Inc. All rights reserved.

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

PubMed

Jalaja, K; Sreehari, V S; Kumar, P R Anil; Nirmala, R James

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±0.53MPa to 21±2.03MPa 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±2.03MPa. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

Supercapacitors based on 3D network of activated carbon nanowhiskers wrapped-on graphitized electrospun nanofibers

NASA Astrophysics Data System (ADS)

He, Shuijian; Chen, Linlin; Xie, Chencheng; Hu, Huan; Chen, Shuiliang; Hanif, Muddasir; Hou, Haoqing

2013-12-01

Due to their cycling stability and high power density, the supercapacitors bridge the power/energy gap between traditional dielectric capacitors and batteries/fuel cells. Electrode materials are key components for making high performance supercapacitors. An activated carbon nanowhiskers (ACNWs) wrapped-on graphitized electrospun nanofiber (GENF) network (ACNWs/GENFN) with 3D porous structure is prepared as a new type of binder-free electrode material for supercapacitors. The supercapacitor based on the ACNWs/GENFN composite material displays an excellent performance with a specific capacitance of 176.5 F g-1 at current density of 0.5 A g-1, an ultrahigh power density of 252.8 kW kg-1 at current density of 800 A g-1 and an outstanding cycling stability of no capacitance loss after 10,000 charge/discharge cycles.

Amperometric sensor for ethanol based on one-step electropolymerization of thionine-carbon nanofiber nanocomposite containing alcohol oxidase.

PubMed

Wu, Lina; McIntosh, Mike; Zhang, Xueji; Ju, Huangxian

2007-12-15

Thionine had strong interaction with carbon nanofiber (CNF) and was used in the non-covalent functionalization of carbon nanofiber for the preparation of stable thionine-CNF nanocomposite with good dispersion. With a simple one-step electrochemical polymerization of thionine-CNF nanocomposite and alcohol oxidase (AOD), a stable poly(thionine)-CNF/AOD biocomposite film was formed on electrode surface. Based on the excellent catalytic activity of the biocomposite film toward reduction of dissolved oxygen, a sensitive ethanol biosensor was proposed. The ethanol biosensor could monitor ethanol ranging from 2.0 to 252 microM with a detection limit of 1.7 microM. It displayed a rapid response, an expanded linear response range as well as excellent reproducibility and stability. The combination of catalytic activity of CNF and the promising feature of the biocomposite with one-step non-manual technique favored the sensitive determination of ethanol with improved analytical capabilities.

Analysis and Modeling of Fullerene Single Electron Transistor Based on Quantum Dot Arrays at Room Temperature

NASA Astrophysics Data System (ADS)

Khadem Hosseini, Vahideh; Ahmadi, Mohammad Taghi; Ismail, Razali

2018-05-01

The single electron transistor (SET) as a fast electronic device is a candidate for future nanoscale circuits because of its low energy consumption, small size and simplified circuit. It consists of source and drain electrodes with a quantum dot (QD) located between them. Moreover, it operates based on the Coulomb blockade (CB) effect. It occurs when the charging energy is greater than the thermal energy. Consequently, this condition limits SET operation at cryogenic temperatures. Hence, using QD arrays can overcome this temperature limitation in SET which can therefore work at room temperature but QD arrays increase the threshold voltage with is an undesirable effect. In this research, fullerene as a zero-dimensional material with unique properties such as quantum capacitance and high critical temperature has been selected for the material of the QDs. Moreover, the current of a fullerene QD array SET has been modeled and its threshold voltage is also compared with a silicon QD array SET. The results show that the threshold voltage of fullerene SET is lower than the silicon one. Furthermore, the comparison study shows that homogeneous linear QD arrays have a lower CB range and better operation than a ring QD array SET. Moreover, the effect of the number of QDs in a QD array SET is investigated. The result confirms that the number of QDs can directly affect the CB range. Moreover, the desired current can be achieved by controlling the applied gate voltage and island diameters in a QD array SET.

Facile synthesis of NiS anchored carbon nanofibers for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Xu, Jinling; Zhang, Li; Xu, Guancheng; Sun, Zhipeng; Zhang, Chi; Ma, Xin; Qi, Chunling; Zhang, Lu; Jia, Dianzeng

2018-03-01

Transition metal sulfide compounds with carbon materials are promising for high-performance supercapacitors. Carbon nanofibers (CNFs) wrapped with NiS nanoparticles were herein obtained through electrospinning and calcination. NiS nanoparticles in composite nanofibers are covered by a layer of graphitic carbon, which not only increase the conductivity but also provide active regions for nanoparticle growth to prevent aggregation. The CNFs-NiS electrode has high specific capacity of 177.1 mAh g-1 at 1 A g-1 (0.41 mAh cm-2 at a current density of 2.3 mA cm-2) and long-term cycling stability, with 88.7% capacitance retention after 5000 cycles. The excellent electrochemical activity may be attributed to the accessible specific surface, unique porous structure of CNFs and high specific capacitance of NiS. In addition, the asymmetric supercapacitor has an enhanced volumetric energy density of 13.32 mWh cm-3 at a volumetric power density of 180 mW cm-3 and high cycling stability, with 89.5% capacitance retention after 5000 cycles. It also successfully lights up a light-emitting diode. The CNFs-NiS composite has significant potential applications in supercapacitor.

Optical nanofiber temperature monitoring via double heterodyne detection

NASA Astrophysics Data System (ADS)

Anderson, P.; Jalnapurkar, S.; Moiseev, E. S.; Chang, D.; Barclay, P. E.; Lezama, A.; Lvovsky, A. I.

2018-05-01

Tapered optical fibers (nanofibers) whose diameters are smaller than the optical wavelength are very fragile and can be easily destroyed if excessively heated by energy dissipated from the transmitted light. We present a technique for monitoring the nanofiber temperature using two-stage heterodyne detection. The phase of the heterodyne output signal is determined by that of the transmitted optical field, which, in turn, depends on the temperature through the refractive index. From the phase data, by numerically solving the heat exchange equations, the temperature distribution along the nanofiber is determined. The technique is applied to the controlled heating of the nanofiber by a laser in order to remove rubidium atoms adsorbed on its surface that substantially degrade its transmission. Almost 90% of the nanofiber's original transmission is recovered.

Distinguishing the importance of fullerene phase separation from polymer ordering in the performance of low band gap polymer: Bis-fullerene heterojunctions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Huipeng; Hsiao, Yu -Che; Chen, Jihua

2014-09-16

It is known, one way to improve power conversion efficiency (PCE) of polymer based bulk-heterojunction (BHJ) photovoltaic cells is to increase the open circuit voltage (V oc). Replacing PCBM with bis-adduct fullerenes significantly improves V oc and the PCE in devices based on the conjugated polymer poly(3-hexyl thiophene) (P3HT). However, for the most promising low band-gap polymer (LBP) system, replacing PCBM with ICBA results in poor short-circuit current (J sc) and PCE although V oc is significantly improved. The optimization of the morphology of as-cast LBP/bis-fullerene BHJ photovoltaics is attempted by adding a co-solvent to the polymer/fullerene solution prior tomore » film deposition. Varying the solubility of polymer and fullerene in the co-solvent, bulk heterojunctions are fabricated with no change of polymer ordering, but with changes in fullerene phase separation. The morphologies of the as-cast samples are characterized by small angle neutron scattering and neutron reflectometry. A homogenous dispersion of ICBA in LBP is found in the samples where the co-solvent is selective to the polymer, giving poor device performance. Aggregates of ICBA are formed in samples where the co-solvent is selective to ICBA. Furthermore, the resultant morphology improves PCE by up to 246%. Finally, a quantitative analysis of the neutron data shows that the interfacial area between ICBA aggregates and its surrounding matrix is improved, facilitating charge transport and improving the PCE.« less

Two-chamber configuration of Bio-Nano electron cyclotron resonance ion source for fullerene modification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uchida, T., E-mail: uchida-t@toyo.jp; Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe 350-8585; Rácz, R.

2016-02-15

We report on the modification of fullerenes with iron and chlorine using two individually controllable plasmas in the Bio-Nano electron cyclotron resonance ion source (ECRIS). One of the plasmas is composed of fullerene and the other one is composed of iron and chlorine. The online ion beam analysis allows one to investigate the rate of the vapor-phase collisional modification process in the ECRIS, while the offline analyses (e.g., liquid chromatography-mass spectrometry) of the materials deposited on the plasma chamber can give information on the surface-type process. Both analytical methods show the presence of modified fullerenes such as fullerene-chlorine, fullerene-iron, andmore » fullerene-chlorine-iron.« less

Controllable preparation of fluorine-containing fullerene-like carbon film

NASA Astrophysics Data System (ADS)

Wang, Jia; Liang, Aimin; Wang, Fuguo; Xu, Longhua; Zhang, Junyan

2016-05-01

Fluorine-containing fullerene-like carbon (F-FLC) films were prepared by high frequency unipolar pulse plasma-enhanced chemical vapor deposition. The microstructures, mechanical properties as well as the tribological properties of the films were investigated. The results indicate that fullerene-like microstructures appear in amorphous carbon matrix and increase greatly with the increase of bias voltage from -600 to -1600 V. And the fluorine contents in F-FLC films also show a minor rise. In addition, the hardness enhances with the bias voltage and the outstanding elastic recovery maintains because of the formation of fullerene-like microstructures in the F-FLC films. Undoubtedly, the F-FLC film deposited under high bias voltage owns a superiorly low friction, which combines the merits of fluorinated carbon film and fullerene-like carbon film. Moreover, the film also shows a remarkable wear resistance, which is mainly attributed to the excellent mechanical properties. This study provides new insights for us to prepare fluorine-containing FLC films with good mechanical and tribological properties.

Graphene-passivated cobalt as a spin-polarized electrode: growth and application to organic spintronics

NASA Astrophysics Data System (ADS)

Zhou, Guoqing; Tang, Guoqiang; Li, Tian; Pan, Guoxing; Deng, Zanhong; Zhang, Fapei

2017-03-01

The ferromagnetic electrode on which a clean high-quality electrode/interlayer interface is formed, is critical to achieve efficient injection of spin-dependent electrons in spintronic devices. In this work, we report on the preparation of graphene-passivated cobalt electrodes for application in vertical spin valves (SVs). In this strategy, high-quality monolayer and bi-layer graphene sheets have been grown directly on the crystal Co film substrates in a controllable process by chemical vapor deposition. The electrode is oxidation resistant and ensures a clean crystalline graphene/Co interface. The AlO x -based magnetic junction devices using such bottom electrodes, exhibit a negative tunnel magneto-resistance (TMR) of ca. 1.0% in the range of 5 K-300 K. Furthermore, we have also fabricated organic-based SVs employing a thin layer of fullerene C60 or an N-type polymeric semiconductor as the interlayer. The devices of both materials show a tunneling behavior of spin-polarized electron transport as well as appreciable TMR effect, demonstrating the high potential of such graphene-coated Co electrodes for organic-based spintronics.

Cooperative tin oxide fullerene electron selective layers for high-performance planar perovskite solar cells

DOE PAGES

Ke, Weijun; Zhao, Dewei; Xiao, Chuanxiao; ...

2016-08-17

Both tin oxide (SnO 2) and fullerenes have been reported as electron selective layers (ESLs) for producing efficient lead halide perovskite solar cells. Here, we report that SnO 2 and fullerenes can work cooperatively to further boost the performance of perovskite solar cells. We find that fullerenes can be redissolved during perovskite deposition, allowing ultra-thin fullerenes to be retained at the interface and some dissolved fullerenes infiltrate into perovskite grain boundaries. The SnO 2 layer blocks holes effectively; whereas, the fullerenes promote electron transfer and passivate both the SnO 2/perovskite interface and perovskite grain boundaries. With careful device optimization, themore » best-performing planar perovskite solar cell using a fullerene passivated SnO 2 ESL has achieved a steady-state efficiency of 17.75% and a power conversion efficiency of 19.12% with an open circuit voltage of 1.12 V, a short-circuit current density of 22.61 mA cm -2, and a fill factor of 75.8% when measured under reverse voltage scanning. In conclusion, we find that the partial dissolving of fullerenes during perovskite deposition is the key for fabricating high-performance perovskite solar cells based on metal oxide/fullerene ESLs.« less

Unconventional molecule-resolved current rectification in diamondoid–fullerene hybrids

PubMed Central

Randel, Jason C.; Niestemski, Francis C.; Botello-Mendez, Andrés R.; Mar, Warren; Ndabashimiye, Georges; Melinte, Sorin; Dahl, Jeremy E. P.; Carlson, Robert M. K.; Butova, Ekaterina D.; Fokin, Andrey A.; Schreiner, Peter R.; Charlier, Jean-Christophe; Manoharan, Hari C.

2014-01-01

The unimolecular rectifier is a fundamental building block of molecular electronics. Rectification in single molecules can arise from electron transfer between molecular orbitals displaying asymmetric spatial charge distributions, akin to p–n junction diodes in semiconductors. Here we report a novel all-hydrocarbon molecular rectifier consisting of a diamantane–C60 conjugate. By linking both sp3 (diamondoid) and sp2 (fullerene) carbon allotropes, this hybrid molecule opposingly pairs negative and positive electron affinities. The single-molecule conductances of self-assembled domains on Au(111), probed by low-temperature scanning tunnelling microscopy and spectroscopy, reveal a large rectifying response of the molecular constructs. This specific electronic behaviour is postulated to originate from the electrostatic repulsion of diamantane–C60 molecules due to positively charged terminal hydrogen atoms on the diamondoid interacting with the top electrode (scanning tip) at various bias voltages. Density functional theory computations scrutinize the electronic and vibrational spectroscopic fingerprints of this unique molecular structure and corroborate the unconventional rectification mechanism. PMID:25202942

Organic solar cells based on non-fullerene acceptors

NASA Astrophysics Data System (ADS)

Hou, Jianhui; Inganäs, Olle; Friend, Richard H.; Gao, Feng

2018-02-01

Organic solar cells (OSCs) have been dominated by donor:acceptor blends based on fullerene acceptors for over two decades. This situation has changed recently, with non-fullerene (NF) OSCs developing very quickly. The power conversion efficiencies of NF OSCs have now reached a value of over 13%, which is higher than the best fullerene-based OSCs. NF acceptors show great tunability in absorption spectra and electron energy levels, providing a wide range of new opportunities. The coexistence of low voltage losses and high current generation indicates that new regimes of device physics and photophysics are reached in these systems. This Review highlights these opportunities made possible by NF acceptors, and also discuss the challenges facing the development of NF OSCs for practical applications.

Computational investigation of fullerene-DNA interactions: Implications of fullerene's size and functionalization on DNA structure and binding energetics.

PubMed

Papavasileiou, Konstantinos D; Avramopoulos, Aggelos; Leonis, Georgios; Papadopoulos, Manthos G

2017-06-01

DNA is the building block of life, as it carries the biological information controlling development, function and reproduction of all organisms. However, its central role in storing and transferring genetic information can be severely hindered by molecules with structure altering abilities. Fullerenes are nanoparticles that find a broad spectrum of uses, but their toxicological effects on living organisms upon exposure remain unclear. The present study examines the interactions of a diverse array of fullerenes with DNA, by means of Molecular Dynamics and MM-PBSA methodologies, with special focus on structural deformations that may hint toxicity implications. Our results show that pristine and hydroxylated fullerenes have no unwinding effects upon DNA structure, with the latter displaying binding preference to the DNA major groove, achieved by both direct formation of hydrogen bonds and water molecule mediation. Fluorinated derivatives are capable of penetrating DNA structure, forming intercalative complexes with high binding affinities. Copyright © 2017 Elsevier Inc. All rights reserved.

Recent advances in electrospun nanofibers for wound healing.

PubMed

Chen, Shixuan; Liu, Bing; Carlson, Mark A; Gombart, Adrian F; Reilly, Debra A; Xie, Jingwei

2017-06-01

Electrospun nanofibers represent a novel class of materials that show great potential in many biomedical applications including biosensing, regenerative medicine, tissue engineering, drug delivery and wound healing. In this work, we review recent advances in electrospun nanofibers for wound healing. This article begins with a brief introduction on the wound, and then discusses the unique features of electrospun nanofibers critical for wound healing. It further highlights recent studies that have used electrospun nanofibers for wound healing applications and devices, including sutures, multifunctional dressings, dermal substitutes, engineered epidermis and full-thickness skin regeneration. Finally, we finish with conclusions and future perspective in this field.

The quest for inorganic fullerenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pietsch, Susanne; Dollinger, Andreas; Strobel, Christoph H.

2015-10-07

Experimental results of the search for inorganic fullerenes are presented. Mo{sub n}S{sub m}{sup −} and W{sub n}S{sub m}{sup −} clusters are generated with a pulsed arc cluster ion source equipped with an annealing stage. This is known to enhance fullerene formation in the case of carbon. Analogous to carbon, the mass spectra of the metal chalcogenide clusters produced in this way exhibit a bimodal structure. The species in the first maximum at low mass are known to be platelets. Here, the structure of the species in the second maximum is studied by anion photoelectron spectroscopy, scanning transmission electron microscopy, andmore » scanning tunneling microcopy. All experimental results indicate a two-dimensional structure of these species and disagree with a three-dimensional fullerene-like geometry. A possible explanation for this preference of two-dimensional structures is the ability of a two-element material to saturate the dangling bonds at the edges of a platelet by excess atoms of one element. A platelet consisting of a single element only cannot do this. Accordingly, graphite and boron might be the only materials forming nano-spheres because they are the only single element materials assuming two-dimensional structures.« less

Organic-Inorganic Nanostructure Architecture via Directly Capping Fullerenes onto Quantum Dots.

PubMed

Lee, Jae Kwan; Kim, Jonggi; Yang, Changduk

2011-12-01

A new form of fullerene-capped CdSe nanoparticles (PCBA-capped CdSe NPs), using carboxylate ligands with [60]fullerene capping groups that provides an effective synthetic methodology to attach fullerenes noncovalently to CdSe, is presented for usage in nanotechnology and photoelectric fields. Interestingly, either the internal charge transfer or the energy transfer in the hybrid material contributes to photoluminescence (PL) quenching of the CdSe moieties.

Organo-Soluble Porphyrin Mixed Monolayer-Protected Gold Nanorods with Intercalated Fullerenes

DTIC Science & Technology

2012-03-16

Mixed Monolayer- Protected Gold Nanorods with Intercalated Fullerenes Chenming Xue, Yongqian Xu, Yi Pang, Dingshan Yu, Liming Dai, Min Gao, Augustine...Protected Gold Nanorods with Intercalated Fullerenes 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT... Fullerenes Chenming Xue, † Yongqian Xu, ‡ Yi Pang, ‡ Dingshan Yu, § Liming Dai, § Min Gao, † Augustine Urbas ± and Quan

Preparation and characterization of kefiran electrospun nanofibers.

PubMed

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.

Polymer-fullerene miscibility: a metric for screening new materials for high-performance organic solar cells.

PubMed

Treat, Neil D; Varotto, Alessandro; Takacs, Christopher J; Batara, Nicolas; Al-Hashimi, Mohammed; Heeney, Martin J; Heeger, Alan J; Wudl, Fred; Hawker, Craig J; Chabinyc, Michael L

2012-09-26

The improvement of the power conversion efficiency (PCE) of polymer bulk heterojunction (BHJ) solar cells has generally been achieved through synthetic design to control frontier molecular orbital energies and molecular ordering of the electron-donating polymer. An alternate approach to control the PCE of a BHJ is to tune the miscibility of the fullerene and a semiconducting polymer by varying the structure of the fullerene. The miscibility of a series of 1,4-fullerene adducts in the semiconducting polymer, poly(3-hexylselenophene), P3HS, was measured by dynamic secondary ion mass spectrometry using a model bilayer structure. The microstructure of the bilayer was investigated using high-angle annular dark-field scanning transmission microscopy and linked to the polymer-fullerene miscibility. Finally, P3HS:fullerene BHJ solar cells were fabricated from each fullerene derivative, enabling the correlation of the active layer microstructure to the charge collection efficiency and resulting PCE of each system. The volume fraction of polymer-rich, fullerene-rich, and polymer-fullerene mixed domains can be tuned using the miscibility leading to improvement in the charge collection efficiency and PCE in P3HS:fullerene BHJ solar cells. These results suggest a rational approach to the design of fullerenes for improved BHJ solar cells.

Self-organization processes in polysiloxane block copolymers, initiated by modifying fullerene additives

NASA Astrophysics Data System (ADS)

Voznyakovskii, A. P.; Kudoyarova, V. Kh.; Kudoyarov, M. F.; Patrova, M. Ya.

2017-08-01

Thin films of a polyblock polysiloxane copolymer and their composites with a modifying fullerene C60 additive are studied by atomic force microscopy, Rutherford backscattering, and neutron scattering. The data of atomic force microscopy show that with the addition of fullerene to the bulk of the polymer matrix, the initial relief of the film surface is leveled more, the larger the additive. This trend is associated with the processes of self-organization of rigid block sequences, which are initiated by the field effect of the surface of fullerene aggregates and lead to an increase in the number of their domains in the bulk of the polymer matrix. The data of Rutherford backscattering and neutron scattering indicate the formation of additional structures with a radius of 60 nm only in films containing fullerene, and their fraction increases with increasing fullerene concentration. A comparative analysis of the data of these methods has shown that such structures are, namely, the domains of a rigid block and are not formed by individual fullerene aggregates. The interrelation of the structure and mechanical properties of polymer films is considered.

The Electronic Structure of Transition Metal Coated Fullerenes

NASA Astrophysics Data System (ADS)

Patton, David C.; Pederson, Mark R.; Kaxiras, Efthimios

1998-03-01

Clusters composed of fullerene molecules with an outer shell of transition metal atoms in the composition C_60M_62 (M being a transition metal) have been produced with laser vaporisation techniques(F. Tast, N. Malinowski, S. Frank, M. Heinebrodt, I.M.L. Billas, and T. P. Martin, Z. Phys D 40), 351 (1997).. We have studied several of these very large systems with a parallel version of the all-electron NRLMOL cluster code. Optimized geometries of the metal encased fullerenes C_60Ti_62 and C_60V_62 are presented along with their HOMO-LUMO gaps, electron affinities, ionization energies, and cohesive energies. We compare the stability of these clusters to relaxed met-car structures (e.g. Ti_8C_12) and to relaxed rocksalt metal-carbide fragments (TiC)n with n=8 and 32. In addition to metal-coated fullerenes we consider the possibility of a trilayered structure consisting of a small shell of metal atoms enclosed by a metal coated fullerene. The nature of bonding in these systems is analyzed by studying the electronic charge distributions.

Fullerene-Based Symmetry in Hibiscus rosa-sinensis Pollen

PubMed Central

Andrade, Kleber; Guerra, Sara; Debut, Alexis

2014-01-01

The fullerene molecule belongs to the so-called super materials. The compound is interesting due to its spherical configuration where atoms occupy positions forming a mechanically stable structure. We first demonstrate that pollen of Hibiscus rosa-sinensis has a strong symmetry regarding the distribution of its spines over the spherical grain. These spines form spherical hexagons and pentagons. The distance between atoms in fullerene is explained applying principles of flat, spherical, and spatial geometry, based on Euclid’s “Elements” book, as well as logic algorithms. Measurements of the pollen grain take into account that the true spine lengths, and consequently the real distances between them, are measured to the periphery of each grain. Algorithms are developed to recover the spatial effects lost in 2D photos. There is a clear correspondence between the position of atoms in the fullerene molecule and the position of spines in the pollen grain. In the fullerene the separation gives the idea of equal length bonds which implies perfectly distributed electron clouds while in the pollen grain we suggest that the spines being equally spaced carry an electrical charge originating in forces involved in the pollination process. PMID:25003375

Nanofiber adsorbents for high productivity downstream processing.

PubMed

Hardick, Oliver; Dods, Stewart; Stevens, Bob; Bracewell, Daniel G

2013-04-01

Electrospun polymeric nanofiber adsorbents offer an alternative ligand support surface for bioseparations. Their non-woven fiber structure with diameters in the sub-micron range creates a remarkably high surface area. To improve the purification productivity of biological molecules by chromatography, cellulose nanofiber adsorbents were fabricated and assembled into a cartridge and filter holder format with a volume of 0.15 mL, a bed height of 0.3 mm and diameter of 25 mm. The present study investigated the performance of diethylaminoethyl (DEAE) derivatized regenerated cellulose nanofiber adsorbents based on criteria including mass transfer and flow properties, binding capacity, and fouling effects. Our results show that nanofibers offer higher flow and mass transfer properties. The non-optimized DEAE-nanofiber adsorbents indicate a binding capacity of 10% that of packed bed systems with BSA as a single component system. However, they operate reproducibly at flowrates of a hundred times that of packed beds, resulting in a potential productivity increase of 10-fold. Lifetime studies showed that this novel adsorbent material operated reproducibly with complex feed material (centrifuged and 0.45 µm filtered yeast homogenate) and harsh cleaning-in-place conditions over multiple cycles. DEAE nanofibers showed superior operating performance in permeability and fouling over conventional adsorbents indicating their potential for bioseparation applications. Copyright © 2012 Wiley Periodicals, Inc.

Next-generation organic photovoltaics based on non-fullerene acceptors

NASA Astrophysics Data System (ADS)

Cheng, Pei; Li, Gang; Zhan, Xiaowei; Yang, Yang

2018-03-01

Over the past three years, a particularly exciting and active area of research within the field of organic photovoltaics has been the use of non-fullerene acceptors (NFAs). Compared with fullerene acceptors, NFAs possess significant advantages including tunability of bandgaps, energy levels, planarity and crystallinity. To date, NFA solar cells have not only achieved impressive power conversion efficiencies of 13-14%, but have also shown excellent stability compared with traditional fullerene acceptor solar cells. This Review highlights recent progress on single-junction and tandem NFA solar cells and research directions to achieve even higher efficiencies of 15-20% using NFA-based organic photovoltaics are also proposed.

Table of periodic properties of fullerenes based on structural parameters.

PubMed

Torrens, Francisco

2004-01-01

The periodic table (PT) of the elements suggests that hydrogen could be the origin of everything else. The construction principle is an evolutionary process that is formally similar to those of Darwin and Oparin. The Kekulé structure count and permanence of the adjacency matrix of fullerenes are related to structural parameters involving the presence of contiguous pentagons p, q and r. Let p be the number of edges common to two pentagons, q the number of vertices common to three pentagons, and r the number of pairs of nonadjacent pentagon edges shared between two other pentagons. Principal component analysis (PCA) of the structural parameters and cluster analysis (CA) of the fullerenes permit classifying them and agree. A PT of the fullerenes is built based on the structural parameters, PCA and CA. The periodic law does not have the rank of the laws of physics. (1) The properties of the fullerenes are not repeated; only, and perhaps, their chemical character. (2) The order relationships are repeated, although with exceptions. The proposed statement is the following: The relationships that any fullerene p has with its neighbor p + 1 are approximately repeated for each period.

A new microplatform based on titanium dioxide nanofibers/graphene oxide nanosheets nanocomposite modified screen printed carbon electrode for electrochemical determination of adenine in the presence of guanine.

PubMed

Arvand, Majid; Ghodsi, Navid; Zanjanchi, Mohammad Ali

2016-03-15

The current techniques for determining adenine have several shortcomings such as high cost, high time consumption, tedious pretreatment steps and the requirements for highly skilled personnel often restrict their use in routine analytical practice. This paper describes the development and utilization of a new nanocomposite consisting of titanium dioxide nanofibers (TNFs) and graphene oxide nanosheets (GONs) for screen printed carbon electrode (SPCE) modification. The synthesized GONs and TNFs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The modified electrode (TNFs/GONs/SPCE) was used for electrochemical characterization of adenine. The TNFs/GONs/SPCE exhibited an increase in peak current and the electron transfer kinetics and decrease in the overpotential for the oxidation reaction of adenine. Using differential pulse voltammetry (DPV), the prepared sensor showed good sensitivity for determining adenine in two ranges from 0.1-1 and 1-10 μM, with a detection limit (DL) of 1.71 nM. Electrochemical studies suggested that the TNFs/GONs/SPCE provided a synergistic augmentation on the voltammetric behavior of electrochemical oxidation of adenine, which was indicated by the improvement of anodic peak current and a decrease in anodic peak potential. The amount of adenine in pBudCE4.1 plasmid was determined via the proposed sensor and the result was in good compatibility with the sequence data of pBudCE4.1 plasmid. Copyright © 2015 Elsevier B.V. All rights reserved.

Endohedral fullerenes: Synthesis, isolation, mono- and bis -functionalization

DOE PAGES

Cerón, Maira R.; Maffeis, Viviana; Stevenson, Steven; ...

2017-03-29

Here, in this paper, we present a short overview of the contribution of our research group to the discovery, functionalization and characterization of unprecedented endohedral fullerenes. We also report a comprehensive study of regioselective bis-1,3-dipolar cycloadditions to cluster endohedral fullerenes M 3N@I h-C 80 (M = Lu, Y and Er) and the spectroscopic characterization of the new bis-adducts obtained.

Nanofiber electrode and method of forming same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pintauro, Peter N.; Zhang, Wenjing

In one aspect, a method of forming an electrode for an electrochemical device is disclosed. In one embodiment, the method includes the steps of mixing at least a first amount of a catalyst and a second amount of an ionomer or uncharged polymer to form a solution and delivering the solution into a metallic needle having a needle tip. The method further includes the steps of applying a voltage between the needle tip and a collector substrate positioned at a distance from the needle tip, and extruding the solution from the needle tip at a flow rate such as tomore » generate electrospun fibers and deposit the generated fibers on the collector substrate to form a mat with a porous network of fibers. Each fiber in the porous network of the mat has distributed particles of the catalyst. The method also includes the step of pressing the mat onto a membrane.« less

Coaxial nanofibers containing TiO2 in the shell for water treatment applications

NASA Astrophysics Data System (ADS)

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.

Nanocomposites based on hierarchical porous carbon fiber@vanadium nitride nanoparticles as supercapacitor electrodes.

PubMed

Ran, Fen; Wu, Yage; Jiang, Minghuan; Tan, Yongtao; Liu, Ying; Kong, Lingbin; Kang, Long; Chen, Shaowei

2018-03-28

In this study, a hybrid electrode material for supercapacitors based on hierarchical porous carbon fiber@vanadium nitride nanoparticles is fabricated using the method of phase-separation mediated by the PAA-b-PAN-b-PAA tri-block copolymer. In the phase-separation procedure, the ionic block copolymer self-assembled on the surface of carbon nanofibers, and is used to adsorb NH 4 VO 3 . Thermal treatment at controlled temperatures under an NH 3  : N 2 atmosphere led to the formation of vanadium nitride nanoparticles that are distributed uniformly on the nanofiber surface. By changing the PAN to PAA-b-PAN-b-PAA ratio in the casting solution, a maximum specific capacitance of 240.5 F g -1 is achieved at the current density of 0.5 A g -1 with good rate capability at a capacitance retention of 72.1% at 5.0 A g -1 in an aqueous electrolyte of 6 mol L -1 KOH within the potential range of -1.10 to 0 V (rN/A = 1.5/1.0). Moreover, an asymmetric supercapacitor is assembled by using the hierarchical porous carbon fiber@vanadium nitride as the negative electrode and Ni(OH) 2 as the positive electrode. Remarkably, at the power density of 400 W kg -1 , the supercapacitor device delivers a better energy density of 39.3 W h kg -1 . It also shows excellent electrochemical stability, and thus might be used as a promising energy-storage device.

Synthesis of Keratin-based Nanofiber for Biomedical Engineering.

PubMed

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.

Biomedical applications of ferulic acid encapsulated electrospun nanofibers.

PubMed

Vashisth, Priya; Kumar, Naresh; Sharma, Mohit; Pruthi, Vikas

2015-12-01

Ferulic acid is a ubiquitous phytochemical that holds enormous therapeutic potential but has not gained much consideration in biomedical sector due to its less bioavailability, poor aqueous solubility and physiochemical instability. In present investigation, the shortcomings associated with agro-waste derived ferulic acid were addressed by encapsulating it in electrospun nanofibrous matrix of poly (d,l-lactide-co-glycolide)/polyethylene oxide. Fluorescent microscopic analysis revealed that ferulic acid predominantly resides in the core of PLGA/PEO nanofibers. The average diameters of the PLGA/PEO and ferulic acid encapsulated PLGA/PEO nanofibers were recorded as 125 ± 65.5 nm and 150 ± 79.0 nm, respectively. The physiochemical properties of fabricated nanofibers are elucidated by IR, DSC and NMR studies. Free radical scavenging activity of fabricated nanofibers were estimated using di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH) assay. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay confirmed the cytotoxicity of ferulic acid encapsulated nanofibers against hepatocellular carcinoma (HepG2) cells. These ferulic acid encapsulated nanofibers could be potentially explored for therapeutic usage in biomedical sector.

Extraterrestrial Helium (He@C60) Trapped in Fullerenes in the Sudbury Impact Structure

NASA Technical Reports Server (NTRS)

Becker, L.; Bada, J. L.; Poreda, R. J.; Bunch, T. E.

1997-01-01

Fullerenes (C60 and C70) have recently been identified in a shock-produced breccia (Onaping Formation) associated with the 1.85-Ga Sudbury Impact Crater. The presence of parts-per-million levels of fullerenes in this impact structure raises interesting questions about the processes that led to the formation of fullerenes and the potential for delivery of intact organic material to the Earth by a large bolide (e.g., asteroid or comet). Two possible scenarios for the presence of fullerenes in the Sudbury impact deposits are that (1) fullerenes are synthesized within the impact plume from the C contained in the bolide; or (2) fullerenes are already present in the bolide and survived the impact event. The correlation of C and trapped noble gas atoms in meteorites is well established. Primitive meteorites contain several trapped noble gas components that have anomalous isotopic compositions, some of which may have a presolar origin. Several C-bearing phases, including SiC, graphite, and diamond, have been recognized as carriers of trapped noble gases. It has also been suggested that fullerenes (C60 and C70) might be a carrier of noble gas components in carbonaceous chondrites. Recently, fullerenes have been detected in separate samples in the Allende meteorite. Carbon-60 is large enough to enclose the noble gases He, Ne, Ar, Kr, and Xe, but it is too small to contain diatomic gases such as N2 or triatomic gases such as CO2. Recent experimental work has demonstrated that noble gases of a specific isotopic composition can be introduced into synthetic fullerenes at high temperatures and pressures; these encapsulated gases can then be released by the breaking of one or more C bonds during step-heating under vacuum. These thermal-release patterns for He encapsulated within the C60 molecule (He@C60) are similar to the patterns for acid residues of carbonaceous chondrites, suggesting that fullerenes could be an additional carrier of trapped noble gases in acid residues of

Enhancing fullerene-based solar cell lifetimes by addition of a fullerene dumbbell.

PubMed

Schroeder, Bob C; Li, Zhe; Brady, Michael A; Faria, Gregório Couto; Ashraf, Raja Shahid; Takacs, Christopher J; Cowart, John S; Duong, Duc T; Chiu, Kar Ho; Tan, Ching-Hong; Cabral, João T; Salleo, Alberto; Chabinyc, Michael L; Durrant, James R; McCulloch, Iain

2014-11-17

Cost-effective, solution-processable organic photovoltaics (OPV) present an interesting alternative to inorganic silicon-based solar cells. However, one of the major remaining challenges of OPV devices is their lack of long-term operational stability, especially at elevated temperatures. The synthesis of a fullerene dumbbell and its use as an additive in the active layer of a PCDTBT:PCBM-based OPV device is reported. The addition of only 20 % of this novel fullerene not only leads to improved device efficiencies, but more importantly also to a dramatic increase in morphological stability under simulated operating conditions. Dynamic secondary ion mass spectrometry (DSIMS) and TEM are used, amongst other techniques, to elucidate the origins of the improved morphological stability. © 2014 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Nanocontainers in and onto Nanofibers.

PubMed

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

Drug functionalized microbial polysaccharide based nanofibers as transdermal substitute.

PubMed

Vashisth, Priya; Srivastava, Amit Kumar; Nagar, Hemant; Raghuwanshi, Navdeep; Sharan, Shruti; Nikhil, Kumar; Pruthi, Parul A; Singh, Rajesh P; Roy, Partha; Pruthi, Vikas

2016-07-01

In order to promote the natural healing process, drug-functionalized nanofibrous transdermal substitute was fabricated using gellan as chief polymer and polyvinyl alcohol (PVA) as supporting polymer via electrospinning technique. These fabricated nanofibers physiochemically mimic the extracellular matrix (ECM) which supports the cell growth. For neo-tissue regeneration in a sterilized environment, amoxicillin (Amx) was entrapped within these nanofibers. Entrapment of Amx in the nanofibers was confirmed by FESEM, FTIR, XRD and TG analysis. In vitro cell culture studies revealed that the fabricated non-cytotoxic nanofibers promoted enhance cell adherence and proliferation of human keratinocytes. A preliminary in vivo study performed on rat model for full thickness skin excision wound demonstrated the prompt re-epithelialization in early phase and quicker collagen deposition in later phases of wound healing in case of Amx-functionalized gellan/PVA nanofibers. Data collectively confirmed the potential usage of gellan based electrospun nanofibers as transdermal substitute for faster skin restoration. Copyright © 2016 Elsevier Inc. All rights reserved.

Vibrational Spectra of Tetrahedral Fullerenes.

PubMed

Cheng; Li; Tang

1999-01-01

From the topological structures of the following classes of tetrahedral fullerenes-(1) Cn(h, h; -i, i), Cn(h, 0; -i, 2i), Cn(2h + i, -h + i; i, i), Cn(h - i, h + 2i; -i, 2i), and Cn(h, i; 0, i) for Td symmetry; (2) Cn(h, k; k, h), Cn(h, k; -h - k, k), and Cn(h, k; -h, h + k) for Th symmetry; (3) Cn(h, k; i, j) for T symmetry-we have obtained theoretically the formulas for the numbers of their IR and Raman active modes for all of the tetrahedral fullerenes through the decomposition of their nuclear motions into irreducible representations by means of group theory. Copyright 1999 Academic Press.

Fullerenes, carbon nanotubes, and graphene for molecular electronics.

PubMed

Pinzón, Julio R; Villalta-Cerdas, Adrián; Echegoyen, Luis

2012-01-01

With the constant growing complexity of electronic devices, the top-down approach used with silicon based technology is facing both technological and physical challenges. Carbon based nanomaterials are good candidates to be used in the construction of electronic circuitry using a bottom-up approach, because they have semiconductor properties and dimensions within the required physical limit to establish electrical connections. The unique electronic properties of fullerenes for example, have allowed the construction of molecular rectifiers and transistors that can operate with more than two logical states. Carbon nanotubes have shown their potential to be used in the construction of molecular wires and FET transistors that can operate in the THz frequency range. On the other hand, graphene is not only the most promising material for replacing ITO in the construction of transparent electrodes but it has also shown quantum Hall effect and conductance properties that depend on the edges or chemical doping. The purpose of this review is to present recent developments on the utilization carbon nanomaterials in molecular electronics.

High-performance symmetric supercapacitors based on carbon nanotube/graphite nanofiber nanocomposites.

PubMed

Zhou, Yongsheng; Jin, Pan; Zhou, Yatong; Zhu, Yingchun

2018-06-13

This work reports the nanocomposites of graphitic nanofibers (GNFs) and carbon nanotubes (CNTs) as the electrode material for supercapacitors. The hybrid CNTs/GNFs was prepared via a synthesis route that involved catalytic chemical vapor deposition (CVD) method. The structure and morphology of CNTs/GNFs can be precisely controlled by adjusting the flow rates of reactant gases. The nest shape entanglement of CNTs and GNFs which could not only have high conductivity to facilitate ion transmission, but could also increase surface area for more electrolyte ions access. When assembled in a symmetric two-electrode system, the CNTs/GNFs-based supercapacitor showed a very good cycling stability of 96% after 10 000 charge/discharge cycles. Moreover, CNTs/GNFs-based symmetric device can deliver a maximum specific energy of 72.2 Wh kg -1 at a power density of 686.0 W kg -1 . The high performance of the hybrid performance can be attributed to the wheat like GNFs which provide sufficient accessible sites for charge storage, and the CNTs skeleton which provide channels for charge transport.

Improving effects of chitosan nanofiber scaffolds on osteoblast proliferation and maturation

PubMed Central

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

Simulation of the Impact of Si Shell Thickness on the Performance of Si-Coated Vertically Aligned Carbon Nanofiber as Li-Ion Battery Anode

PubMed Central

Das, Susobhan; Li, Jun; Hui, Rongqing

2015-01-01

Micro- and nano-structured electrodes have the potential to improve the performance of Li-ion batteries by increasing the surface area of the electrode and reducing the diffusion distance required by the charged carriers. We report the numerical simulation of Lithium-ion batteries with the anode made of core-shell heterostructures of silicon-coated carbon nanofibers. We show that the energy capacity can be significantly improved by reducing the thickness of the silicon anode to the dimension comparable or less than the Li-ion diffusion length inside silicon. The results of simulation indicate that the contraction of the silicon electrode thickness during the battery discharge process commonly found in experiments also plays a major role in the increase of the energy capacity. PMID:28347120

Nanofiber Filters Eliminate Contaminants

NASA Technical Reports Server (NTRS)

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.

Nitrogen anion-decorated cobalt tungsten disulfides solid solutions on the carbon nanofibers for water splitting.

PubMed

Wan, Meng; Li, Jiang; Li, Tao; Zhu, Han; Wu, Weiwei; Du, Mingliang

2018-06-28

A facile method to prepared nitrogen anion-decorated cobalt tungsten disulfides solid solutions retaining ultra-thin WS2-like nanosheet structures (The N-CoxW1-xS2) anchored on carbon nanofibers is developed. The synergistic effect of the WS2 nanosheets provides a secure framework for stabilizing the amorphous Co-S clusters, carbon nanofibers (CNFs) substrate and nitrogen anion-decoration significantly enhances the inherent conductivity of the catalyst, resulting in a significantly promoted hydrogen evolution reaction (HER) activity and stable performance compared to pure Co9S8 nanoparticles or ultra-thin WS2 nanosheets. The N-CoxW1-xS2 electrode demonstrates the excellent electrocatalytic performance, with current density of 10 mA cm-2 at a low overpotential of 93 mV and Tafel slope of 85 mV dec-1, as well as the long-term stability in acid electrolyte. The present investigation may provide a feasible strategy for incorporating other heteroatoms into transitional metal disulfides (TMDs) materials to design catalysts with highly active and stable performance for water splitting. © 2018 IOP Publishing Ltd.

Detection of fullerenes (C60 and C70) in commercial cosmetics.

PubMed

Benn, Troy M; Westerhoff, Paul; Herckes, Pierre

2011-05-01

Detection methods are necessary to quantify fullerenes in commercial applications to provide potential exposure levels for future risk assessments of fullerene technologies. The fullerene concentrations of five cosmetic products were evaluated using liquid chromatography with mass spectrometry to separate and specifically detect C60 and C70 from interfering cosmetic substances (e.g., castor oil). A cosmetic formulation was characterized with transmission electron microscopy, which confirmed that polyvinylpyrrolidone encapsulated C60. Liquid-liquid extraction of fullerenes from control samples approached 100% while solid-phase and sonication in toluene extractions yielded recoveries of 27-42%. C60 was detected in four commercial cosmetics ranging from 0.04 to 1.1 μg/g, and C70 was qualitatively detected in two samples. A single-use quantity of cosmetic (0.5 g) may contain up to 0.6 μg of C60, demonstrating a pathway for human exposure. Steady-state modeling of fullerene adsorption to biosolids is used to discuss potential environmental releases from wastewater treatment systems. Copyright © 2011 Elsevier Ltd. All rights reserved.

Detection of fullerenes (C60 and C70) in commercial cosmetics

PubMed Central

Benn, Troy M.; Westerhoff, Paul; Herckes, Pierre

2013-01-01

Detection methods are necessary to quantify fullerenes in commercial applications to provide potential exposure levels for future risk assessments of fullerene technologies. The fullerene concentrations of five cosmetic products were evaluated using liquid chromatography with mass spectrometry to separate and specifically detect C60 and C70 from interfering cosmetic substances (e.g., castor oil). A cosmetic formulation was characterized with transmission electron microscopy, which confirmed that polyvinylpyrrolidone encapsulated C60. Liquid-liquid extraction of fullerenes from control samples approached 100% while solid-phase and sonication in toluene extractions yielded recoveries of 27–42%. C60 was detected in four commercial cosmetics ranging from 0.04 to 1.1 μg/g, and C70 was qualitatively detected in two samples. A single-use quantity of cosmetic (0.5 g) may contain up to 0.6 μg of C60, demonstrating a pathway for human exposure. Steady-state modeling of fullerene adsorption to biosolids is used to discuss potential environmental releases from wastewater treatment systems. PMID:21300421

Solution blowing of chitosan/PVA hydrogel nanofiber mats.

PubMed

Liu, Ruifang; Xu, Xianlin; Zhuang, Xupin; Cheng, Bowen

2014-01-30

Both nanofiber mats and hydrogel have their own advantages in wound healing. In this study, a novel hydrogel nanofiber mats were fabricated via solution blowing of chitosan and PVA solution, with various content of ethylene glycol diglycidyl ether (EGDE) as cross-linker. SEM observation showed that the fibers were several hundred nanometers in diameter with smooth surface and distributed randomly forming three-dimensional mats. The structure of the chitosan/PVA nanofibers was examined by FTIR and XPS, and the results showed that the cross-linking reaction occurred between EGDE and the hydroxyl groups. The mats could quickly hydrate in an aqueous environment to form hydrogel. Their value of equilibrate water absorption varied from 680 to 459% various content of EGDE. The nanofiber mats showed good bactericidal activity against Escherichia coli. The chitosan/PVA hydrogel nanofiber mats showed the combination advantages of nanofibrous mats and hydrogel dressing, and were suggested as potential application in wound healing. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fabrication of free-standing hierarchical carbon nanofiber/graphene oxide/polyaniline films for supercapacitors.

PubMed

Xu, Dongdong; Xu, Qun; Wang, Kaixi; Chen, Jun; Chen, Zhimin

2014-01-08

A hierarchical high-performance electrode with nanoacanthine-style polyaniline (PANI) deposited onto a carbon nanofiber/graphene oxide (CNF/GO) template was successfully prepared via an in situ polymerization process. The morphology analysis shows that introducing one-dimensional (1D) CNF could significantly decrease/inhibit the staking of laminated GO to form an open-porous CNF/GO architecture. Followed with in situ facial deposition of PANI, the as-synthesized PANI modified CNF/GO exhibits three-dimensional (3D) hierarchical layered nanoarchitecture, which favors the diffusion of the electrolyte ions into the inner region of active materials. The hierarchical free-standing electrodes were directly fabricated into sandwich structured supercapacitors using 1 M H2SO4 as the electrolyte showing a significant specific capacitance of 450.2 F/g at the voltage scan rate of 10 mV/s. The electrochemical properties of the hierarchical structure can be further improved by a reduction procedure of GO before the deposition of PANI.

Synthesis of Continuous Boron Nitride Nanofibers by Electrospinning

NASA Astrophysics Data System (ADS)

Li, Xia; Wen, G.; Zhang, Tao; Xia, Long; Zhong, Bo; Fan, Shaoyu

Continuous boron nitride nanofibers (BNNFs) have been gotten by electrospinning. The appropriate precursor of BNNFs was electrospinned to green born nitride nanofibers (GBNNFs) with temperatures from 80°C to 100°C in the protection of N2. By successive heat treatments in N2, the organics in GBNNFs disappeared and BN ceramics nanofibers came into being. The average diameters of BNNFs by electrospinning are less than 10 μm

GTC/CanariCam Mid-IR Imaging of the Fullerene-rich Planetary Nebula IC 418: Searching for the Spatial Distribution of Fullerene-like Molecules

NASA Astrophysics Data System (ADS)

Díaz-Luis, J. J.; García-Hernández, D. A.; Manchado, A.; García-Lario, P.; Villaver, E.; García-Segura, G.

2018-03-01

We present seeing-limited narrow-band mid-IR GTC/CanariCam images of the spatially extended fullerene-containing planetary nebula (PN) IC 418. The narrow-band images cover the C60 fullerene band at 17.4 μm, the polycyclic aromatic hydrocarbon like (PAH-like) feature at 11.3 μm, the broad 9–13 μm feature, and their adjacent continua at 9.8 and 20.5 μm. We study the relative spatial distribution of these complex species, all detected in the Spitzer and Infrared Space Observatory spectra of IC 418, with the aim of getting observational constraints to the formation process of fullerenes in H-rich circumstellar environments. A similar ring-like extended structure is seen in all narrow-band filters, except in the dust continuum emission at 9.8 μm, which peaks closer to the central star. The continuum-subtracted images display a clear ring-like extended structure for the carrier of the broad 9–13 μm emission, while the spatial distribution of the (PAH-like) 11.3 μm emission is not so well defined. Interestingly, a residual C60 17.4 μm emission (at about 4σ from the sky background) is seen when subtracting the dust continuum emission at 20.5 μm. This residual C60 emission, if real, might have several interpretations, the most exciting being perhaps that other fullerene-based species like hydrogenated fullerenes with very low H-content may contribute to the observed 17.4 μm emission. We conclude that higher sensitivity mid-IR images and spatially resolved spectroscopic observations (especially in the Q-band) are necessary to get some clues about fullerene formation in PNe.

The Electrospun Ceramic Hollow Nanofibers

PubMed Central

Davoudpour, Yalda; Habibi, Youssef; Elbahri, Mady

2017-01-01

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. PMID:29120403

Carbon Nanofiber Nanoelectrodes for Neural Stimulation and Chemical Detection: The Era of "Smart" Deep Brain Stimulation

NASA Technical Reports Server (NTRS)

Koehne, Jessica E.

2016-01-01

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 two studies using vertically aligned CNF nanoelectrodes for biomedical applications. CNF arrays are investigated as neural stimulation and neurotransmitter recording electrodes for application in deep brain stimulation (DBS). Polypyrrole coated CNF nanoelectrodes have shown great promise as stimulating electrodes due to their large surface area, low impedance, biocompatibility and capacity for highly localized stimulation. CNFs embedded in SiO2 have been used as sensing electrodes for neurotransmitter detection. 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.

Carbon Nanofiber Nanoelectrodes for Neural Stimulation and Chemical Detection: The Era of Smart Deep Brain Stimulation

NASA Technical Reports Server (NTRS)

Koehne, Jessica E.

2016-01-01

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 two studies using vertically aligned CNF nanoelectrodes for biomedical applications. CNF arrays are investigated as neural stimulation and neurotransmitter recording electrodes for application in deep brain stimulation (DBS). Polypyrrole coated CNF nanoelectrodes have shown great promise as stimulating electrodes due to their large surface area, low impedance, biocompatibility and capacity for highly localized stimulation. CNFs embedded in SiO2 have been used as sensing electrodes for neurotransmitter detection. 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.

Improved energy storage, magnetic and electrical properties of aligned, mesoporous and high aspect ratio nanofibers of spinel-NiMn2O4

NASA Astrophysics Data System (ADS)

Bhagwan, Jai; Rani, Stuti; Sivasankaran, V.; Yadav, K. L.; Sharma, Yogesh

2017-12-01

Spinel-NiMn2O4 (NMO) nanofibers of high aspect ratio, high surface area (50 m2 g-1) and homogeneous pore size distribution are fabricated by electrospinning process and characterized by XRD, FTIR, XPS, BET, FESEM, TEM techniques. Further, multifunctional properties (energy storage properties, magnetic and electrical properties) of NMO nanofibers are also examined. High specific capacitance (Cs) of 410 (±5) F g-1 at 1 A g-1, good rate capability and high cycling stability (up to 5000 cycles) are demonstrated by NMO nanofibers. Furthermore, NMO-based solid-state symmetric supercapacitor (SSSC) shows a high Cs of 170 (±5) F g-1 at 0.5 A g-1 in potential range of 0.0V-2.0 V and exhibits excellent energy density of ∼95 W h kg-1 and power density of 1030 W Kg-1. The above storage properties i.e. high energy density and output voltage of 2.0 V are further supplemented by lighting up a red colored LED (1.8 V @ current 20 mA) at least for 5 min. The ionic diffusion coefficient of NMO based electrode is found to be ∼4.84 × 10-11 cm2 s-1. Magnetic and dielectric properties of NMO nanofibers are also examined and results are discussed.

High-yield harvest of nanofibers/mesoporous carbon composite by pyrolysis of waste biomass and its application for high durability electrochemical energy storage.

PubMed

Liu, Wu-Jun; Tian, Ke; He, Yan-Rong; Jiang, Hong; Yu, Han-Qing

2014-12-02

Disposal and recycling of the large scale biomass waste is of great concern. Themochemically converting the waste biomass to functional carbon nanomaterials and bio-oil is an environmentally friendly apporach by reducing greenhouse gas emissions and air pollution caused by open burning. In this work, we reported a scalable, "green" method for the synthesis of the nanofibers/mesoporous carbon composites through pyrolysis of the Fe(III)-preloaded biomass, which is controllable by adjustment of temperature and additive of catalyst. It is found that the coupled catalytic action of both Fe and Cl species is able to effectively catalyze the growth of the carbon nanofibers on the mesoporous carbon and form magnetic nanofibers/mesoporous carbon composites (M-NMCCs). The mechanism for the growth of the nanofibers is proposed as an in situ vapor deposition process, and confirmed by the XRD and SEM results. M-NMCCs can be directly used as electrode materials for electrochemical energy storage without further separation, and exhibit favorable energy storage performance with high EDLC capacitance, good retention capability, and excellent stability and durability (more than 98% capacitance retention after 10,000 cycles). Considering that biomass is a naturally abundant and renewable resource (over billions tons biomass produced every year globally) and pyrolysis is a proven technique, M-NMCCs can be easily produced at large scale and become a sustainable and reliable resource for clean energy storage.

Arc Synthesis of Fullerenes from the Carbide of Waste Cloths

NASA Astrophysics Data System (ADS)

Hayashi, Koichiro; Mieno, Tetsu

2000-09-01

A great many scraps of cotton cloth are disposed of as industrial waste through making clothes. The purpose of this study is to transform the waste into very valuable carbon compounds, that is, fullerenes. The scraps were piled and carbonized in air at 1050°C. By carbonization, the weight of the scraps decreased to 16-18%. Carbide from the scraps was used as the raw material for synthesizing fullerenes with the \\mbi{J}×\\mbi{B} arc discharge method. The soot that was deposited on the inside of the vacuum chamber contained C60 (>0.05 wt%), C70 and higher fullerenes.

Photoionization and Photofragmentation of Carbon Fullerene Molecular Ions

NASA Astrophysics Data System (ADS)

Baral, Kiran Kumar

Cross sections are reported for single and double photoionization accompanied by the loss of as many as seven pairs of C atoms of C60 + and C70+ fullerene molecular ions in the photon energy range 18 eV to 150 eV. These measurements were performed at the Advanced Light Source (ALS) by merging a mass-selected ion beam with a beam of monochromatized synchrotron radiation. Threshold energies were determined for the formation of doubly and triply charged fragment ions from parent ions C60+ and C70+. The energy dependences of cross-sections for direct photoionization yielding C60 2+ and C702+ are compared with those for forming different doubly and triply charged fullerene fragment ions. Two-dimensional product ion scans were measured and quantified at four discrete photon energies: 35 eV, 65 eV, 105 eV and 140 eV, in the vacuum ultraviolet region, providing a comprehensive mapping of the product channels involving single ionization of fullerene ions C60+ and C 70+ accompanied by fragmentation. Since fullerenes are composed of even numbers of carbon atoms, the fragmentation occurs by the loss of differing numbers of carbon atom pairs. In addition to pure ionization, fragmentation product channels become relatively more important at higher photon energies.

Novel Dental Composites Reinforced with Zirconia-Silica Ceramic Nanofibers

PubMed Central

Guo, Guangqing; Fan, Yuwei; Zhang, Jian-Feng; Hagan, Joseph; Xu, Xiaoming

2011-01-01

Objective To fabricate and characterize dental composites reinforced with various amounts of zirconia-silica (ZS) or zirconia-yttria-silica (ZYS) ceramic nanofibers. Methods Control composites (70 wt% glass particle filler, no nanofibers) and experimental composites (2.5, 5.0, and 7.5 wt% ZS or ZYS nanofibers replacing glass particle filler) were prepared by blending 29 wt% dental resin monomers, 70 wt% filler, and 1.0 wt% initiator, and polymerized by either heat or dental curing light. Flexural strength (FS), flexural modulus (FM), energy at break (EAB), and fracture toughness (FT) were tested after the specimens were stored in 37 °C deionized water for 24 h, 3 months, or 6 months. Degree of conversion (DC) of monomers in composites was measured using Fourier transformed near-infrared (FT-NIR) spectroscopy. Fractured surfaces were observed by field-emission scanning electron microscope (FE-SEM). The data were analyzed using ANOVA with Tukey’s Honestly Significant Differences test used for post hoc analysis. Results Reinforcement of dental composites with ZS or ZYS nanofibers (2.5% or 5.0%) can significantly increase the FS, FM and EAB of dental composites over the control. Further increase the content of ZS nanofiber (7.5%), however, decreases these properties (although they are still higher than those of the control). Addition of nanofibers did not decrease the long-term mechanical properties of these composites. All ZS reinforced composites (containing 2.5%, 5.0% and 7.5% ZS nanofibers) exhibit significantly higher fracture toughness than the control. The DC of the composites decreases with ZS nanofiber content. Significance Incorporation of ceramic nanofibers in dental composites can significantly improve their mechanical properties and fracture toughness and thus may extend their service life. PMID:22153326

Novel dental composites reinforced with zirconia-silica ceramic nanofibers.

PubMed

Guo, Guangqing; Fan, Yuwei; Zhang, Jian-Feng; Hagan, Joseph L; Xu, Xiaoming

2012-04-01

To fabricate and characterize dental composites reinforced with various amounts of zirconia-silica (ZS) or zirconia-yttria-silica (ZYS) ceramic nanofibers. Control composites (70 wt% glass particle filler, no nanofibers) and experimental composites (2.5, 5.0, and 7.5 wt% ZS or ZYS nanofibers replacing glass particle filler) were prepared by blending 29 wt% dental resin monomers, 70 wt% filler, and 1.0 wt% initiator, and polymerized by either heat or dental curing light. Flexural strength (FS), flexural modulus (FM), energy at break (EAB), and fracture toughness (FT) were tested after the specimens were stored in 37°C deionized water for 24h, 3 months, or 6 months. Degree of conversion (DC) of monomers in composites was measured using Fourier transformed near-infrared (FT-NIR) spectroscopy. Fractured surfaces were observed by field-emission scanning electron microscope (FE-SEM). The data were analyzed using ANOVA with Tukey's Honestly Significant Differences test used for post hoc analysis. Reinforcement of dental composites with ZS or ZYS nanofibers (2.5% or 5.0%) can significantly increase the FS, FM and EAB of dental composites over the control. Further increase the content of ZS nanofiber (7.5%), however, decreases these properties (although they are still higher than those of the control). Addition of nanofibers did not decrease the long-term mechanical properties of these composites. All ZS reinforced composites (containing 2.5%, 5.0% and 7.5% ZS nanofibers) exhibit significantly higher fracture toughness than the control. The DC of the composites decreases with ZS nanofiber content. Incorporation of ceramic nanofibers in dental composites can significantly improve their mechanical properties and fracture toughness and thus may extend their service life. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Carbon Nanotubes Embedded in Oriented Polymer Nanofibers by Electrospinning

NASA Astrophysics Data System (ADS)

Cohen, Yachin; Dror, Yael; Khalfin, Rafail L.; Salalha, Wael; Yarin, Alexander L.; Zussman, Eyal

2004-03-01

The electrospinning process was used successfully to fabricate nanofibers of poly(ethylene oxide) [PEO] in which carbon nanotubes, either multi-walled (MWCNT) or single-walled (SWCNT) are embedded. MWCNTs were dispersed in water using SDS or Gum Arabic - a highly branched polyelectrolyte. Aqueous dispersion of SWCNT's was achieved using an alternating copolymer of styrene and maleic anhydride, hydrolyzed with NaOH. The focus of this work is on the development of axial orientations in the multi-component nanofibers. The degree of orientation of polymers, surfactants and nanotubes was studied using X-ray diffraction and transmission electron microscopy. Individual nanotubes were successfully embedded in the polymer nanofibers with good axial alignment. A high degree of alignment of PEO crystals and SDS layers was also found in the electrospun nanofibers containing SWCNT's. Oriented ropes of the nanofibers were fabricated in a converging electric field by a rotating disc with a tapered edge. These results can lead to further usage of the nanofibers with embedded carbon nanotubes in applications such as nano-scale energy storage devices.

Electronic structure evolution of fullerene on CH 3NH 3PbI 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Chenggong; Wang, Congcong; Liu, Xiaoliang

2015-03-19

The thickness dependence of fullerene on CH 3NH 3PbI 3 perovskitefilm surface has been investigated by using ultraviolet photoemission spectroscopy (UPS), X-ray photoemission spectroscopy(XPS), and inverse photoemission spectroscopy (IPES). The lowest unoccupied molecular orbital and highest occupied molecular orbital (HOMO) can be observed directly with IPES and UPS. It is observed that the HOMO level in fullerene shifts to lower binding energy. The XPS results show a strong initial shift of core levels to lower binding energy in the perovskite, which indicates that electrons transfer from the perovskitefilm to fullerene molecules. Further deposition of fullerene forms C 60 solid, accompaniedmore » by the reduction of the electron transfer. As a result, the strongest electron transfer happened at 1/4 monolayer of fullerene.« less

Benzene Adsorption on C24, Si@C24, Si-Doped C24, and C20 Fullerenes

NASA Astrophysics Data System (ADS)

Baei, Mohammad T.

2017-12-01

The absorption feasibility of benzene molecule in the C24, Si@C24, Si-doped C24, and C20 fullerenes has been studied based on calculated electronic properties of these fullerenes using Density functional Theory (DFT). It is found that energy of benzene adsorption on C24, Si@C24, and Si-doped C24 fullerenes were in range of -2.93 and -51.19 kJ/mol with little changes in their electronic structure. The results demonstrated that the C24, Si@C24, and Si-doped C24 fullerenes cannot be employed as a chemical adsorbent or sensor for benzene. Silicon doping cannot significantly modify both the electronic properties and benzene adsorption energy of C24 fullerene. On the other hand, C20 fullerene exhibits a high sensitivity, so that the energy gap of the fullerene is changed almost 89.19% after the adsorption process. We concluded that the C20 fullerene can be employed as a reliable material for benzene detection.

Superhydrophilicity of novel anodic alumina nanofibers films and their formation mechanism

NASA Astrophysics Data System (ADS)

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.

Classical Dynamics of Fullerenes

NASA Astrophysics Data System (ADS)

Sławianowski, Jan J.; Kotowski, Romuald K.

2017-06-01

The classical mechanics of large molecules and fullerenes is studied. The approach is based on the model of collective motion of these objects. The mixed Lagrangian (material) and Eulerian (space) description of motion is used. In particular, the Green and Cauchy deformation tensors are geometrically defined. The important issue is the group-theoretical approach to describing the affine deformations of the body. The Hamiltonian description of motion based on the Poisson brackets methodology is used. The Lagrange and Hamilton approaches allow us to formulate the mechanics in the canonical form. The method of discretization in analytical continuum theory and in classical dynamics of large molecules and fullerenes enable us to formulate their dynamics in terms of the polynomial expansions of configurations. Another approach is based on the theory of analytical functions and on their approximations by finite-order polynomials. We concentrate on the extremely simplified model of affine deformations or on their higher-order polynomial perturbations.

Preparation of fullerene/glass composites

DOEpatents

Mattes, Benjamin R.; McBranch, Duncan W.; Robinson, Jeanne M.; Koskelo, Aaron C.; Love, Steven P.

1995-01-01

Synthesis of fullerene/glass composites. A direct method for preparing solid solutions of C.sub.60 in silicon dioxide (SiO.sub.2) glass matrices by means of sol-gel chemistry is described. In order to produce highly concentrated fullerene-sol-gel-composites it is necessary to increase the solubility of these "guests" in a delivery solvent which is compatible with the starter sol (receiving solvent). Sonication results in aggregate disruption by treatment with high frequency sound waves, thereby accelerating the rate of hydrolysis of the alkoxide precursor, and the solution process for the C.sub.60. Depending upon the preparative procedure, C.sub.60 dispersed within the glass matrix as microcrystalline domains, or dispersed as true molecular solutions of C.sub.60 in a solid glass matrix, is generated by the present method.

Adsorption of alanine with heteroatom substituted fullerene for solar cell application: A DFT study.

PubMed

Dheivamalar, S; Sugi, L; Ravichandran, K; Sriram, S

2018-09-05

C 20 is the most important fullerene cage and alanine is the simplest representation of a backbone unit of the protein. The absorption feasibility of alanine molecule in the Si-doped C 20 and B-doped C 20 fullerenes has been studied based on calculated electronic properties of fullerenes using density functional theory (DFT). In this work, we explore the ability of Si-doped C 20 , B-doped C 20 fullerene to interact with alanine at the DFT-B3LYP/6-31G, RHF level of theory. We find that noticeable structural change takes place in C 20 when one of its carbon is substituted with Si or B. The molecular geometry, electronic properties and vibrational analysis have also been performed on the title compounds. The NMR study reveals the aromaticity of the pure and doped fullerene compounds. Stability of the doped fullerene - alanine compound arises from hyper conjugative interactions. It leads to one of the major property of bioactivity, charge transfer and delocalization of charge and this properties has been analyzed using Natural Bond Orbital (NBO) analysis. The energy gap of the doped fullerene reveals that there is a decrease in the size of energy gap significantly, making them more reactive as compared to C 20 fullerene. Theoretical studies of the electronic spectra by using time - dependent density functional theory (TD-DFT) method were helpful to interpret the observed electronic transition state. We aim to optimize the performance of the solar cells by altering the frontier orbital energy gaps. Considering all studied properties, it may be inferred that the applicability of C 20 fullerene as the non-linear optical (NLO) material and its NLO property would increase on doping fullerene with Si and B atom. Specifically C 19 Si would be better among them. Copyright © 2018. Published by Elsevier B.V.

Electrospun nanofiber-based thermite textiles and their reactive properties.

PubMed

Yan, Shi; Jian, Guoqiang; Zachariah, Michael R

2012-12-01

In this work, we present a first time fabrication of thermite-based nanofiber mats with a nitrocellulose composite energetic binder to create a new class of energetic 1D nanocomposite. The as prepared thermite based nanofibrous mats were characterized and tested for their burning behavior, and compared with the pure nitrocellulose and nanoaluminum incorporated nanofibers for their combustion performances. Thermite-based nanofibers show enhanced burning rates in combustion tests, which correlate to the mass loading of nanothermite relative to binder in nanofibers. The electrospinning method demonstrates the possibility of avoiding some of the problems associated with melt casting nanometalized propellants.

Fullerene Soot in Eastern China Air: Results from Soot Particle-Aerosol Mass Spectrometer

NASA Astrophysics Data System (ADS)

Wang, J.; Ge, X.; Chen, M.; Zhang, Q.; Yu, H.; Sun, Y.; Worsnop, D. R.; Collier, S.

2015-12-01

In this work, we present for the first time, the observation and quantification of fullerenes in ambient airborne particulate using an Aerodyne Soot Particle - Aerosol Mass Spectrometer (SP-AMS) deployed during 2015 winter in suburban Nanjing, a megacity in eastern China. The laser desorption and electron impact ionization techniques employed by the SP-AMS allow us to differentiate various fullerenes from other aerosol components. Mass spectrum of the identified fullerene soot is consisted by a series of high molecular weight carbon clusters (up to m/z of 2000 in this study), almost identical to the spectral features of commercially available fullerene soot, both with C70 and C60 clusters as the first and second most abundant species. This type of soot was observed throughout the entire study period, with an average mass loading of 0.18 μg/m3, accounting for 6.4% of the black carbon mass, 1.2% of the total organic mass. Temporal variation and diurnal pattern of fullerene soot are overall similar to those of black carbon, but are clearly different in some periods. Combining the positive matrix factorization, back-trajectory and analyses of the meteorological parameters, we identified the petrochemical industrial plants situating upwind from the sampling site, as the major source of fullerene soot. In this regard, our findings imply the ubiquitous presence of fullerene soot in ambient air of industry-influenced area, especially the oil and gas production regions. This study also offers new insights into the characterization of fullerenes from other environmental samples via the advanced SP-AMS technique.

Biocompatible Electroactive Tetra(aniline)-Conjugated Peptide Nanofibers for Neural Differentiation.

PubMed

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.

Proposal of a framework for scale-up life cycle inventory: A case of nanofibers for lithium iron phosphate cathode applications.

PubMed

Simon, Bálint; Bachtin, Krystyna; Kiliç, Ali; Amor, Ben; Weil, Marcel

2016-07-01

Environmental assessments are crucial for the management of the environmental impacts of a product in a rapidly developing world. The design phase creates opportunities for acting on the environmental issues of products using life cycle assessment (LCA). However, the LCA is hampered by a lack of information originating from distinct scales along the product or technology value chain. Many studies have been undertaken to handle similar problems, but these studies are case-specific and do not analyze the development options in the initial design phase. Thus, systematic studies are needed to determine the possible scaling. Knowledge from such screening studies would open the door for developing new methods that can tackle a given scaling problem. The present article proposes a scale-up procedure that aims to generate a new life cycle inventory (LCI) on a theoretical industrial scale, based on information from laboratory experiments. Three techniques are described to obtain the new LCI. Investigation of a laboratory-scale procedure is discussed to find similar industrial processes as a benchmark for describing a theoretical large-scale production process. Furthermore, LCA was performed on a model system of nanofiber electrospinning for Li-ion battery cathode applications. The LCA results support material developers in identifying promising development pathways. For example, the present study pointed out the significant impacts of dimethylformamide on suspension preparation and the power requirements of distinct electrospinning subprocesses. Nanofiber-containing battery cells had greater environmental impacts than did the reference cell, although they had better electrochemical performance, such as better wettability of the electrode, improving the electrode's electrosorption capacity, and longer expected lifetime. Furthermore, material and energy recovery throughout the production chain could decrease the environmental impacts by 40% to 70%, making the nanofiber a

Enhanced H{sub 2} sensing by substituting polyaniline nanoparticles with nanofibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Preetam K., E-mail: preetam.nano@gmail.com; Srivastava, Subodh, E-mail: preetam.nano@gmail.com; Singh, M.

2014-04-24

We have synthesized Polyaniline nanoparticles and nanofibers using chemical oxidation method and tested them for their Hydrogen sensing properties. PANI nanoparticles and nanofibers have demonstrated sensor response of 1.38 and 1.52, respectively. Reaction kinetics has also enhanced in case of PANI nanofibers with response and recovery times of 170 and 95 s, respectively. The increased conductivity, sensor response and reaction kinetics in case of the nanofibers as compared to nanoparticles is attributed to the 1-D conductive channel provided by the nanofibers for faster and better electron transfer.

Recent Advances in Electrospun Nanofiber Interfaces for Biosensing Devices

PubMed Central

Sapountzi, Eleni; Braiek, Mohamed; Chateaux, Jean-François; Lagarde, Florence

2017-01-01

Electrospinning has emerged as a very powerful method combining efficiency, versatility and low cost to elaborate scalable ordered and complex nanofibrous assemblies from a rich variety of polymers. Electrospun nanofibers have demonstrated high potential for a wide spectrum of applications, including drug delivery, tissue engineering, energy conversion and storage, or physical and chemical sensors. The number of works related to biosensing devices integrating electrospun nanofibers has also increased substantially over the last decade. This review provides an overview of the current research activities and new trends in the field. Retaining the bioreceptor functionality is one of the main challenges associated with the production of nanofiber-based biosensing interfaces. The bioreceptors can be immobilized using various strategies, depending on the physical and chemical characteristics of both bioreceptors and nanofiber scaffolds, and on their interfacial interactions. The production of nanobiocomposites constituted by carbon, metal oxide or polymer electrospun nanofibers integrating bioreceptors and conductive nanomaterials (e.g., carbon nanotubes, metal nanoparticles) has been one of the major trends in the last few years. The use of electrospun nanofibers in ELISA-type bioassays, lab-on-a-chip and paper-based point-of-care devices is also highly promising. After a short and general description of electrospinning process, the different strategies to produce electrospun nanofiber biosensing interfaces are discussed. PMID:28813013

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

NASA Astrophysics Data System (ADS)

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.

Nanofibers made of globular proteins.

PubMed

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.

Ammonia Sensing Behaviors of TiO2-PANI/PA6 Composite Nanofibers

PubMed Central

Wang, Qingqing; Dong, Xianjun; Pang, Zengyuan; Du, Yuanzhi; Xia, Xin; Wei, Qufu; Huang, Fenglin

2012-01-01

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. PMID:23235446

Color rendering based on a plasmon fullerene cavity.

PubMed

Tsai, Fu-Cheng; Weng, Cheng-Hsi; Chen, Yu Lim; Shih, Wen-Pin; Chang, Pei-Zen

2018-04-16

Fullerene in the plasmon fullerene cavity is utilized to propagate plasmon energy in order to break the confinement of the plasmonic coupling effect, which relies on the influential near-field optical region. It acts as a plasmonic inductor for coupling gold nano-islands to the gold film; the separation distances of the upper and lower layers are longer than conventional plasmonic cavities. This coupling effect causes the discrete and continuum states to cooperate together in a cavity and produces asymmetric curve lines in the spectra, producing a hybridized resonance. The effect brings about a bright and saturated displaying film with abundant visible colors. In addition, the reflection spectrum is nearly omnidirectional, shifting by only 5% even when the incident angle changes beyond ± 60°. These advantages allow plasmon fullerene cavities to be applied to reflectors, color filters, visible chromatic sensors, and large-area display.

Preparation, characterization and photocatalytic behavior of WO3-fullerene/TiO2 catalysts under visible light

PubMed Central

2011-01-01

WO3-treated fullerene/TiO2 composites (WO3-fullerene/TiO2) were prepared using a sol-gel method. The composite obtained was characterized by BET surface area measurements, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy, and UV-vis analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. Excellent photocatalytic degradation of a MO solution was observed using the WO3-fullerene, fullerene-TiO2, and WO3-fullerene/TiO2 composites under visible light. An increase in photocatalytic activity was observed, and WO3-fullerene/TiO2 has the best photocatalytic activity; it may attribute to the increase of the photo-absorption effect by the fullerene and the cooperative effect of the WO3. PMID:21774800

Chiral zinc phenylalanine nanofibers with fluorescence.

PubMed

Chen, Erdan; Guo, Beidou; Zhang, Baohong; Gan, Li-Hua; Gong, Jian Ru

2011-09-01

Chiral Zn(II)/D-,L-phenylalanine (Phe) bio-coordination polymer nanofibers with fluorescence were prepared by fast coordination-assisted assembly. The synthetic strategy is based on the fact that the Zn2+ ions were linked to oxygen atoms from carboxylate groups of the D- or L-amino acid by coordination interactions to form the chiral polymers. The Zn(II)/D-,L-Phe nanofibers had homogeneous diameters in the range of 700-900 nm and ultra-long length in several hundred micrometers, and the surface of the fiber was extremely smooth. In addition, the enantiomers of Zn(II)/Phe nanofibers exhibited both optical activity and fluorescent property in the solid state, which has great potential for application in the field of biomimetic nanofabrication and micro-/nano-optoelectronics.

Toxicity of Pristine and Chemically Functionalized Fullerenes to White Rot Fungus Phanerochaete chrysosporium

PubMed Central

Ming, Zhu; Feng, Shicheng; Yilihamu, Ailimire; Ma, Qiang; Yang, Shengnan

2018-01-01

Fullerenes are widely produced and applied carbon nanomaterials that require a thorough investigation into their environmental hazards and risks. In this study, we compared the toxicity of pristine fullerene (C60) and carboxylated fullerene (C60-COOH) to white rot fungus Phanerochaete chrysosporium. The influence of fullerene on the weight increase, fibrous structure, ultrastructure, enzyme activity, and decomposition capability of P. chrysosporium was investigated to reflect the potential toxicity of fullerene. C60 did not change the fresh and dry weights of P. chrysosporium but C60-COOH inhibited the weight gain at high concentrations. Both C60 and C60-COOH destroyed the fibrous structure of the mycelia. The ultrastructure of P. chrysosporium was changed by C60-COOH. Pristine C60 did not affect the enzyme activity of the P. chrysosporium culture system while C60-COOH completely blocked the enzyme activity. Consequently, in the liquid culture, P. chrysosporium lost the decomposition activity at high C60-COOH concentrations. The decreased capability in degrading wood was observed for P. chrysosporium exposed to C60-COOH. Our results collectively indicate that chemical functionalization enhanced the toxicity of fullerene to white rot fungi and induced the loss of decomposition activity. The environmental risks of fullerene and its disturbance to the carbon cycle are discussed. PMID:29470407

Elemental and Microscopic Analysis of Naturally Occurring C-O-Si Hetero-Fullerene-Like Structures.

PubMed

Hullavarad, Nilima V; Hullavarad, Shiva S; Fochesatto, Javier

2015-03-01

Carbon exhibits an ability to form a wide range of structures in nature. Under favorable conditions, carbon condenses to form hollow, spheroid fullerenes in an inert atmosphere. Using high resolution FESEM, we have concealed the existence of giant hetero-fullerene like structures in the natural form. Clear, distinct features of connected hexagons and pentagons were observed. Energy dispersive X-ray analysis depth-profile of natural fullerene structures indicates that Russian-doll-like configurations composed of C, 0, and Si rings exist in nature. The analysis is based on an outstanding molecular feature found in the size fraction of aerosols having diameters 150 nm to 1.0 µm. The fullerene like structures, which are ~ 150 nm in diameter, are observed in large numbers. To the best of our knowledge, this is the first direct detailed observation of natural fullerene-like structures. This article reports inadvertent observation of naturally occurring hetero-fullerene-like structures in the Arctic.

KO(t)Bu-Mediated Coupling of Indoles and [60]Fullerene: Transition-Metal-Free and General Synthesis of 1,2-(3-Indole)(hydro)[60]fullerenes.

PubMed

Li, Fei; Haj Elhussin, Imad Elddin; Li, Shengli; Zhou, Hongping; Wu, Jieying; Tian, Yupeng

2015-11-06

Direct coupling of indoles with C60 has been achieved for the first time. Transition-metal-free KO(t)Bu-mediated reaction of indoles to [60]fullerene has been developed as a practical and efficient method for the synthesis of various 1,2-(3-indole)(hydro)[60]fullerenes that are otherwise difficult to direct synthesize in an efficient and selective manner. This methodology tolerates sensitive functionalities such as chloro, ester, and nitro on indole and builds molecular complexity rapidly, with most reactions reaching completion in <1 h. A plausible reaction mechanism is proposed to explain the high regioselectivity at the 3-position of the indoles and the formation of 1,2-(3-indole)(hydro)[60]fullerenes.

Effect of electrospun nanofibers on flexural properties of fiberglass composites

NASA Astrophysics Data System (ADS)

White, Fatima T.

In the present study, sintered electrospun TEOS nanofibers were interleaved in S2 fiberglass woven fabric layers, and composite panels were fabricated using the heated vacuum assisted resin transfer molding (H-VARTM) process. Cured panels were water jet cut to obtain the flexural test coupons. Flexural coupons were then tested using ASTM D7264 standard. The mechanical properties such as flexural strength, ultimate flexural failure strains, flexural modulus, and fiber volume fraction were measured. The S-2 fiberglass composite with the sintered TEOS electrospun nanofibers displayed lower flexural stiffness and strength as compared to the composites that were fabricated using S-2 fiberglass composite without the TEOS electrospun nanofibers. The present study also indicated that the composites fabricated with sintered TEOS electrospun nanofibers have larger failure strains as compared to the ones that were fabricated without the presence of electrospun nanofibers. The study indicates that the nanoengineered composites have better energy absorbing mechanism under flexural loading as compared to conventional fiberglass composites without presence of nanofibers.

Cellulose nanofiber extraction from grass by a modified kitchen blender

NASA Astrophysics Data System (ADS)

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.

Electrochromic device based on electrospun WO{sub 3} nanofibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dulgerbaki, Cigdem; Maslakci, Neslihan Nohut; Komur, Ali Ihsan

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% atmore » 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.« less

Glycofullerenes: Sweet fullerenes vanquish viruses

NASA Astrophysics Data System (ADS)

Vidal, Sébastien

2016-01-01

Fullerene-based dendritic structures coated with 120 sugars can be made in high yields in a relatively short sequence of reactions. The mannosylated compound is shown to inhibit Ebola infection in cells more efficiently than monofullerene-based glycoclusters.

Cold plasma welding of polyaniline nanofibers with enhanced electrical and mechanical properties.

PubMed

Ye, Dong; Yu, Yao; Liu, Lin; Lu, Xinpei; Wu, Yue

2015-12-11

Joining conducting polymer (CP) nanofibers into an interconnected porous network can result in good mechanical and electrical contacts between nanofibers that can be beneficial for the high performance of CP-based devices. Here, we demonstrate the cold welding of polyaniline (PAni) nanofiber loose ends with cold plasma. The room-temperature and atmospheric-pressure helium micro-plasma jet launches highly charged ion bullets at a PAni nanofiber target with high precision and the highly charged ion bullet selectively induces field emission at the sharp nanofiber loose ends. This technique joins nanofiber tips without altering the morphology of the film and protonation thus leading to significantly enhanced electrical and mechanical properties. In addition, this technique has high spatial resolution and is able to selectively weld and dope regions of nanofiber film with promising novel device applications.

Cold plasma welding of polyaniline nanofibers with enhanced electrical and mechanical properties

NASA Astrophysics Data System (ADS)

Ye, Dong; Yu, Yao; Liu, Lin; Lu, Xinpei; Wu, Yue

2015-12-01

Joining conducting polymer (CP) nanofibers into an interconnected porous network can result in good mechanical and electrical contacts between nanofibers that can be beneficial for the high performance of CP-based devices. Here, we demonstrate the cold welding of polyaniline (PAni) nanofiber loose ends with cold plasma. The room-temperature and atmospheric-pressure helium micro-plasma jet launches highly charged ion bullets at a PAni nanofiber target with high precision and the highly charged ion bullet selectively induces field emission at the sharp nanofiber loose ends. This technique joins nanofiber tips without altering the morphology of the film and protonation thus leading to significantly enhanced electrical and mechanical properties. In addition, this technique has high spatial resolution and is able to selectively weld and dope regions of nanofiber film with promising novel device applications.

Preparation of fullerene/glass composites

DOEpatents