scholarly journals Biological effects of carbon nanotubes generated in forest wildfire ecosystems rich in resinous trees on native plants

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3658 ◽  
Author(s):  
Javier Lara-Romero ◽  
Jesús Campos-García ◽  
Nabanita Dasgupta-Schubert ◽  
Salomón Borjas-García ◽  
DK Tiwari ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanostructures ◽  
Biological Effects ◽  
Ice Cores ◽  
Synthetic Methods ◽  
Multiwalled Carbon ◽  
Show Evidence ◽  
Pinus Oocarpa ◽  
Chemical Conditions ◽  
Forest Wildfires

Carbon nanotubes (CNTs) have a broad range of applications and are generally considered human-engineered nanomaterials. However, carbon nanostructures have been found in ice cores and oil wells, suggesting that nature may provide appropriate conditions for CNT synthesis. During forest wildfires, materials such as turpentine and conifer tissues containing iron under high temperatures may create chemical conditions favorable for CNT generation, similar to those in synthetic methods. Here, we show evidence of naturally occurring multiwalled carbon nanotubes (MWCNTs) produced from Pinus oocarpa and Pinus pseudostrobus, following a forest wildfire. The MWCNTs showed an average of 10 walls, with internal diameters of ∼2.5 nm and outer diameters of ∼14.5 nm. To verify whether MWCNT generation during forest wildfires has a biological effect on some characteristic plant species of these ecosystems, germination and development of seedlings were conducted. Results show that the utilization of comparable synthetic MWCNTs increased seed germination rates and the development of Lupinus elegans and Eysenhardtia polystachya, two plants species found in the burned forest ecosystem. The finding provides evidence that supports the generation and possible ecological functions of MWCNTs in nature.

scholarly journals Plasma fluorination of vertically aligned carbon nanotubes: functionalization and thermal stability

2015 ◽  
Vol 6 ◽  
pp. 2263-2271 ◽  
Author(s):  
Claudia Struzzi ◽  
Mattia Scardamaglia ◽  
Axel Hemberg ◽  
Luca Petaccia ◽  
Jean-François Colomer ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Plasma Treatment ◽  
Carbon Nanostructures ◽  
Chemical Properties ◽  
Spectroscopic Techniques ◽  
Multiwalled Carbon ◽  
Desorption Process ◽  
Vertically Aligned ◽  
Physical And Chemical

Grafting of fluorine species on carbon nanostructures has attracted interest due to the effective modification of physical and chemical properties of the starting materials. Various techniques have been employed to achieve a controlled fluorination yield; however, the effect of contaminants is rarely discussed, although they are often present. In the present work, the fluorination of vertically aligned multiwalled carbon nanotubes was performed using plasma treatment in a magnetron sputtering chamber with fluorine diluted in an argon atmosphere with an Ar/F2 ratio of 95:5. The effect of heavily diluted fluorine in the precursor gas mixture is investigated by evaluating the modifications in the nanotube structure and the electronic properties upon plasma treatment. The existence of oxygen-based grafted species is associated with background oxygen species present in the plasma chamber in addition to fluorine. The thermal stability and desorption process of the fluorine species grafted on the carbon nanotubes during the fluorine plasma treatment were evaluated by combining different spectroscopic techniques.

scholarly journals Structural, electronic and photovoltaic characterization of multiwalled carbon nanotubes grown directly on stainless steel

2012 ◽  
Vol 3 ◽  
pp. 360-367 ◽  
Author(s):  
Luca Camilli ◽  
Manuela Scarselli ◽  
Silvano Del Gobbo ◽  
Paola Castrucci ◽  
Eric Gautron ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Stainless Steel ◽  
Electronic Properties ◽  
Multiwalled Carbon Nanotubes ◽  
Silicon Substrate ◽  
Carbon Nanostructures ◽  
Pyrolytic Graphite ◽  
Chemical Vapour ◽  
Multiwalled Carbon ◽  
Aisi 316 Stainless Steel

We have taken advantage of the native surface roughness and the iron content of AISI-316 stainless steel to grow multiwalled carbon nanotubes (MWCNTs) by chemical vapour deposition without the addition of an external catalyst. The structural and electronic properties of the synthesized carbon nanostructures have been investigated by a range of electron microscopy and spectroscopy techniques. The results show the good quality and the high graphitization degree of the synthesized MWCNTs. Through energy-loss spectroscopy we found that the electronic properties of these nanostructures are markedly different from those of highly oriented pyrolytic graphite (HOPG). Notably, a broadening of the π-plasmon peak in the case of MWCNTs is evident. In addition, a photocurrent was measured when MWCNTs were airbrushed onto a silicon substrate. External quantum efficiency (EQE) and photocurrent values were reported both in planar and in top-down geometry of the device. Marked differences in the line shapes and intensities were found for the two configurations, suggesting that two different mechanisms of photocurrent generation and charge collection are in operation. From this comparison, we are able to conclude that the silicon substrate plays an important role in the production of electron–hole pairs.

scholarly journals Quantitative Techniques for Assessing and Controlling the Dispersion and Biological Effects of Multiwalled Carbon Nanotubes in Mammalian Tissue Culture Cells

ACS Nano ◽  
2010 ◽  
Vol 4 (12) ◽  
pp. 7241-7252 ◽  
Author(s):  
Xiang Wang ◽  
Tian Xia ◽  
Susana Addo Ntim ◽  
Zhaoxia Ji ◽  
Saji George ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Tissue Culture ◽  
Multiwalled Carbon Nanotubes ◽  
Biological Effects ◽  
Mammalian Tissue ◽  
Multiwalled Carbon ◽  
Culture Cells ◽  
Tissue Culture Cells

Studies on the Preparation and Characterisation of Carbon Nanostructures

2004 ◽  
Vol 99-100 ◽  
pp. 269-272
Author(s):  
R.J. Kalenczuk ◽  
E. Borowiak-Palen ◽  
T. Pichler ◽  
M. Rümmeli ◽  
J. Fink
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Carbon Nanostructures ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Single Wall Carbon Nanotubes ◽  
Multiwalled Carbon ◽  
New Class ◽  
Chemically Modified ◽  
Transmission Electron

We present a study on the preparation of multiwalled carbon nanotubes (MWCNT) using chemical vapour deposition (CVD). The CVD produced MWCNT and single wall carbon nanotubes (SWCNT) produced with a laser ablation technique were then chemically modified by substituting carbon atoms with boron and nitrogen atoms. The morphology and the crystal structure of the new class of nanostructures were analyzed by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Carbon Nanotubes Grown with Non-Ferromagnetic Catalysts in Alcohol CVD

2010 ◽  
Vol 636-637 ◽  
pp. 703-708 ◽  
Author(s):  
E. Borowiak-Palen ◽  
A. Steplewska ◽  
A. Bachmatiuk ◽  
M.H. Rümmeli ◽  
R.K. Kalenczuk
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Carbon Nanostructures ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Iron Catalysts ◽  
Multiwalled Carbon ◽  
Experimental Conditions ◽  
Transmission Electron ◽  
Synthesis Of Carbon Nanotubes

In this contribution we present high resolution transmission electron microscopy (HR-TEM) and Raman studies on the synthesis of carbon nanotubes using platinum supported on MgO in alcohol - chemical vapour deposition (A-CVD). For comparison copper and iron catalysts mixed with the same metal loading in MgO and the same process parameters in A-CVD have been tested. Our findings show that the choice of catalyst utilized under the same experimental conditions strongly influences the final morphology of the carbon nanostructures. Application of Pt/MgO in CVD results in doublewalled carbon nanotubes (DWCNT) and multiwalled carbon nanotubes (MWCNT). Cu/MgO mixtures lead to the synthesis of copper filled multiwalled carbon nanotubes (Cu-MWCNT) and iron capsules surrounded by multiwalled carbon shells (Fe-MWCS), respectively. Our findings indicate that the three discussed metals interact differently with the substrate leading to the formation of different sized catalyst particles. The analysis of the particles size in the catalyst precursors and in the final products is also described in this contribution.

scholarly journals Fabrication and characterization of branched carbon nanostructures

2016 ◽  
Vol 7 ◽  
pp. 1260-1266 ◽  
Author(s):  
Sharali Malik ◽  
Yoshihiro Nemoto ◽  
Hongxuan Guo ◽  
Katsuhiko Ariga ◽  
Jonathan P Hill
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanostructures ◽  
Mechanical Performance ◽  
Interfacial Strength ◽  
Research Field ◽  
Electrical Performance ◽  
Commercial Application ◽  
Multiwalled Carbon ◽  
Simple Method ◽  
Covalent Bonds

Carbon nanotubes (CNTs) have atomically smooth surfaces and tend not to form covalent bonds with composite matrix materials. Thus, it is the magnitude of the CNT/fiber interfacial strength that limits the amount of nanomechanical interlocking when using conventional CNTs to improve the structural behavior of composite materials through reinforcement. This arises from two well-known, long standing problems in this research field: (a) inhomogeneous dispersion of the filler, which can lead to aggregation and (b) insufficient reinforcement arising from bonding interactions between the filler and the matrix. These dispersion and reinforcement issues could be addressed by using branched multiwalled carbon nanotubes (b-MWCNTs) as it is known that branched fibers can greatly enhance interfacial bonding and dispersability. Therefore, the use of b-MWCNTs would lead to improved mechanical performance and, in the case of conductive composites, improved electrical performance if the CNT filler was better dispersed and connected. This will provide major benefits to the existing commercial application of CNT-reinforced composites in electrostatic discharge materials (ESD): There would be also potential usage for energy conversion, e.g., in supercapacitors, solar cells and Li-ion batteries. However, the limited availability of b-MWCNTs has, to date, restricted their use in such technological applications. Herein, we report an inexpensive and simple method to fabricate large amounts of branched-MWCNTs, which opens the door to a multitude of possible applications.

scholarly journals Characterization of Multiwalled Carbon Nanotubes Dispersing in Water and Association with Biological Effects

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Xuelian Cheng ◽  
Jun Zhong ◽  
Jie Meng ◽  
Man Yang ◽  
Fumin Jia ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Surface Chemistry ◽  
Multiwalled Carbon Nanotubes ◽  
Biomedical Application ◽  
Uv Spectroscopy ◽  
Biological Effects ◽  
Length Distribution ◽  
Multiwalled Carbon ◽  
Physicochemical Features

Biomedical application potentials of carbon nanotubes-based materials have been investigated intensively in recent years; however, characterization and metrology are still facing great technical challenges when the materials are intended to be used as carriers for therapeutics in aqueous solutions. Systematic characterization on the dispersing carbon nanotubes is urgently required and therefore of significance. In this paper multiwalled carbon nanotubes (MWCNTs) with different average lengths or with different oxidation degrees were dispersed in water and characterized systematically by applying UV spectroscopy, SEM, DLS, TGA, XPS, and FTIR. In particular, the characteristic absorption of the carbon nanotubes was analyzed using resolution-fitting technique to establish relations of wavelength and absorption intensity to the size distribution and surface chemistry. Results indicated that the absorption spectra of MWCNTs could reflect the variation of surface chemistry and length distribution of carbon nanotubes dispersed in water by combining with the other measurements. A vascular endothelium cell line was taken as a model to figure out association between physicochemical features and cytotoxicity of the carbon nanotubes. It was showed that the multiwalled carbon nanotubes with different oxidation degrees and similar length distribution exhibited different interaction files to the cells proliferation in a manner of time dependence and concentration dependence.

Influence of Strain States on the Thermal Transport Properties of Single and Multiwalled Carbon Nanostructures

2018 ◽  
Author(s):  
Sushan Nakarmi ◽  
V. U. Unnikrishnan
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Transport Properties ◽  
Thermal Transport ◽  
Carbon Nanostructures ◽  
Electronic Devices ◽  
Mechanical Strain ◽  
Heat Bath ◽  
Multiwalled Carbon ◽  
Thermal Transport Properties

The increasing demand for system miniaturization and high power density energy produces excessive thermal loads on electronic devices with significant mechanical strain. Carbon Nanotubes (CNTs) based devices are found to have excellent thermal transport properties that makes them attractive for thermal management of these miniaturized nano-electronic devices under extreme environments. These conductive nanostructure (carbon nanotubes, graphene, etc.) are often embedded in polymers or other high-strain alloys (the matrix phase), and are used as bridging materials for conductivity (electrical and thermal) with strain resiliency. The effect of strain on the thermal transport properties of these nanostructures have often been overlooked and will be the focus of this work. The thermal conductivity of the nanostructure is obtained in LAMMPS using the Heat-Bath method, which is a reverse non-equilibrium molecular dynamics (RNEMD) simulation strategy. In RNEMD, constant amount of heat is added to and removed from hot and cold regions and the resultant temperature gradient is measured. The effect of strain on the thermal conductivity of the single and multiwalled nanostructures of various configurations will be discussed with specific emphasis on the phonon density of states of nanotubes at different strain states.

Seamless interconnections of sp2-bonded carbon nanostructures via the crystallization of a bridging amorphous carbon joint

2019 ◽  
Vol 6 (1) ◽  
pp. 72-80 ◽  
Author(s):  
Longze Zhao ◽  
Yong Cheng ◽  
Qiaobao Zhang ◽  
Ming-Sheng Wang
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Multiwalled Carbon Nanotubes ◽  
Amorphous Carbon ◽  
Transmission Electron Microscope ◽  
Carbon Nanostructures ◽  
Multiwalled Carbon ◽  
Transmission Electron

Two multiwalled carbon nanotubes are seamlessly joined via the crystallization of an amorphous carbon joint using a transmission electron microscope.

Dynamic Interfaces In Carbon Nanostructures

1999 ◽  
Vol 5 (S2) ◽  
pp. 140-141
Author(s):  
P. M. Ajayan ◽  
F. Banhart
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanostructures ◽  
Electronic Devices ◽  
Multiwalled Carbon ◽  
Multiwalled Nanotubes ◽  
And Topology ◽  
Metastable Structures ◽  
Carbon Onions ◽  
Foreign Materials ◽  
Intense Electron

Carbon nanotubes and carbon onions are two fascinating forms of crystalline nanosize carbons that have received considerable attention in recent years (1,2). The remarkable physical properties of nanotubes make them valuable material for applications ranging from electronic devices to nanoprobes. The dimensions and topology of these structures make them fascinating objects for study. Multiwalled nanotubes and onions are made of concentric graphite layers, with different geometry. Singlewalled nanotubes on the other hand are made of singular graphene cylinders, often self-assembled into larger rope-like structures. Nanotubes can be produced in gram quantities using electric arc or laser ablation. Carbon onions, however, are structures that assemble from carbonaceous soot under intense electron irradiation in an electron microscope. Hence the onions are metastable structures that become unstable and disintegrate in the absence of irradiation.The multiwalled carbon nanotubes and carbon onions have been shown to encapsulate foreign materials (metals, oxides, carbides), either during growth or by capillarity filling (in the case of nanotubes) (1), or during irradiation of metal containing soot (onions) (3).

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