scholarly journals Observation and analysis of the Coulter effect through carbon nanotube and graphene nanopores

2016 ◽  
Vol 374 (2060) ◽  
pp. 20150357 ◽  
Author(s):  
Kumar Varoon Agrawal ◽  
Lee W. Drahushuk ◽  
Michael S. Strano
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Molecular Transport ◽  
Fluid Phase ◽  
Confined Water ◽  
Stochastic Fluctuations ◽  
Wide Range ◽  
Invaluable Tool ◽  
Pore Properties

Carbon nanotubes (CNTs) and graphene are the rolled and flat analogues of graphitic carbon, respectively, with hexagonal crystalline lattices, and show exceptional molecular transport properties. The empirical study of a single isolated nanopore requires, as evidence, the observation of stochastic, telegraphic noise from a blocking molecule commensurate in size with the pore. This standard is used ubiquitously in patch clamp studies of single, isolated biological ion channels and a wide range of inorganic, synthetic nanopores. In this work, we show that observation and study of stochastic fluctuations for carbon nanopores, both CNTs and graphene-based, enable precision characterization of pore properties that is otherwise unattainable. In the case of voltage clamp measurements of long (0.5–1 mm) CNTs between 0.9 and 2.2 nm in diameter, Coulter blocking of cationic species reveals the complex structuring of the fluid phase for confined water in this diameter range. In the case of graphene, we have pioneered the study and the analysis of stochastic fluctuations in gas transport from a pressurized, graphene-covered micro-well compartment that reveal switching between different values of the membrane permeance attributed to chemical rearrangements of individual graphene pores. This analysis remains the only way to study such single isolated graphene nanopores under these realistic transport conditions of pore rearrangements, in keeping with the thesis of this work. In summary, observation and analysis of Coulter blocking or stochastic fluctuations of permeating flux is an invaluable tool to understand graphene and graphitic nanopores including CNTs.

Synthesis and Characterization of Poly(2,5-benzimidazole) (ABPBI) Grafted Carbon Nanotubes

2009 ◽  
Vol 1240 ◽  
Author(s):  
Ji-Ye Kang ◽  
Su-Mi Eo ◽  
Loon-Seng Tan ◽  
Jong-Beom Baek
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Interfacial Adhesion ◽  
Synthesis And Characterization ◽  
Acylation Reaction ◽  
Single Walled Carbon Nanotube ◽  
Mechanical And Electrical Properties ◽  
Multi Walled Carbon Nanotube

AbstractSingle-walled carbon nanotube (SWCNT) and multi-walled carbon nanotube (MWCNT) were functionalized with 3,4-diaminobenzoic acid via “direct” Friedel-Crafts acylation reaction in PPA/P2O5 to afford ortho-diamino-functionalized SWCNT (DIF-SWCNT) and MWCNT (DIF-MWCNT). The resultant DIF-SWCNT and DIF-MWCNT showed improved solubility and dispersibility. To improve interfacial adhesion between CNT and polymer matrix, the grafting of ABPBI onto the surface of DIF-SWCNT (10 wt%) or DIF-MWCNT (10 wt%) was conducted by simple in-situ polymerization of AB monomer, 3,4-diaminobenzoic acid dihydrochloride, in PPA. The resultant ABPBI-g-MWCNT and ABPBI-g-SWCNT showed improved the mechanical and electrical properties.

Characterization of Mechanical Properties of Carbon Nanotubes in Copper-Matrix Nanocomposites

2006 ◽  
Author(s):  
Seunghyun Baik ◽  
Byeongsoo Lim ◽  
Bumjoon Kim ◽  
Untae Sim ◽  
Seyoung Oh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Pure Copper ◽  
Copper Matrix ◽  
Mixing Process ◽  
Mechanical Mixing ◽  
Matrix Nanocomposites ◽  
Coated Carbon

Carbon nanotubes have received considerable attention because of their excellent mechanical properties. In this study, carbon nanotube - copper composites have been sintered by a mechanical mixing process. The interfacial bonding between nanotubes and the copper matrix was improved by coating nanotubes with nickel. Sintered pure copper samples were used as control materials. The displacement rate of nanotube-copper composites was found to increase at 200°C whereas that of nickel-coated nanotue-copper composites significantly decreased. The incorporation of carbon nanotubes and nickel-coated carbon nanotubes in the copper matrix decreased friction coefficients and increased the time up to the onset of scuffing compared with those of pure copper specimens.

Effect of nanomaterials in platinum-decorated carbon nanotube paste-based electrodes for amperometric glucose detection

2008 ◽  
Vol 23 (5) ◽  
pp. 1457-1465 ◽  
Author(s):  
Jining Xie ◽  
Shouyan Wang ◽  
L. Aryasomayajula ◽  
V.K. Varadan
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electrochemical Impedance ◽  
Glucose Sensing ◽  
Electrochemical Characteristics ◽  
Current Response ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Wide Range

The effect of nanomaterials in platinum-decorated, multiwalled, carbon nanotube-based electrodes for amperometric glucose sensing was investigated by a comparative study with other carbon material-based electrodes such as graphite, glassy carbon, and multiwalled carbon nanotubes. Scanning and transmission electron microscopy and x-ray diffraction were used to investigate their morphologies and crystallinities. Electrochemical impedance spectroscopy was conducted to compare the electrochemical characteristics of these electrodes. The glucose-sensing results from the chronoamperometric measurements indicated that carbon nanotubes improve the linearity of the current response to glucose concentrations over a wide range, and that platinum decoration of the carbon nanotubes produces improved electrochemical performance with a higher sensitivity.

Mechanism of Ion Exclusion by Sub-2nm Carbon Nanotube Membranes

2008 ◽  
Vol 1106 ◽  
Author(s):  
Francesco Fornasiero ◽  
Hyung Gyu Park ◽  
Jason K Holt ◽  
Michael Stadermann ◽  
Costas P Grigoropoulos ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electrostatic Interactions ◽  
Ion Selectivity ◽  
Molecular Transport ◽  
Water Desalination ◽  
Oxygen Plasma Treatment ◽  
Nanotube Membranes ◽  
Ion Exclusion ◽  
Carbon Nanotube Membranes

AbstractCarbon nanotubes offer an outstanding platform for studying molecular transport at nanoscale, and have become promising materials for nanofluidics and membrane technology due to their unique combination of physical, chemical, mechanical, and electronic properties. In particular, both simulations and experiments have proved that fluid flow through carbon nanotubes of nanometer size diameter is exceptionally fast compared to what continuum hydrodynamic theories would predict when applied on this length scale, and also, compared to conventional membranes with pores of similar size, such as zeolites. For a variety of applications such as separation technology, molecular sensing, drug delivery, and biomimetics, selectivity is required together with fast flow. In particular, for water desalination, coupling the enhancement of the water flux with selective ion transport could drastically reduce the cost of brackish and seawater desalting. In this work, we study the ion selectivity of membranes made of aligned double-walled carbon nanotubes with sub-2 nm diameter. Negatively charged groups are introduced at the opening of the carbon nanotubes by oxygen plasma treatment. Reverse osmosis experiments coupled with capillary electrophoresis analysis of permeate and feed show significant anion and cation rejection. Ion exclusion declines by increasing ionic strength (concentration) of the feed and by lowering solution pH; also, the highest rejection is observed for the salts (A=anion, C=cation, z= valence) with the greatest zA/zC ratio. Our results strongly support a Donnan-type rejection mechanism, dominated by electrostatic interactions between fixed membrane charges and mobile ions, while steric and hydrodynamic effects appear to be less important. Comparison with commercial nanofiltration membranes for water softening reveals that our carbon nanotube membranes provides far superior water fluxes for similar ion rejection capabilities.

scholarly journals Challenges in characterizing the environmental fate and effects of carbon nanotubes and inorganic nanomaterials in aquatic systems

2018 ◽  
Vol 5 (1) ◽  
pp. 48-63 ◽  
Author(s):  
Peter Laux ◽  
Christian Riebeling ◽  
Andy M. Booth ◽  
Joseph D. Brain ◽  
Josephine Brunner ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Surface Area ◽  
Environmental Fate ◽  
Aquatic Systems ◽  
Inorganic Nanomaterials

Characterization of carbon nanotube dispersions requires measurement of both, concentration and surface area.

Characterization of dispersion of carbon nanotubes in polymer matrices

2012 ◽  
Vol 1371 ◽  
Author(s):  
Laura Peña-Parás ◽  
Hubert Phillips ◽  
Enrique V. Barrera
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Carbon Nanotube ◽  
Vinyl Ester ◽  
Fixed Frequency ◽  
Ultrasonic Probe ◽  
Scanning Electron

ABSTRACTDispersions of carbon nanotube polymer composites were characterized by Raman mapping.Single-walled nanotubes (SWNTs), double-walled nanotubes (DWNTs), multi-walled nanotubes (MWNTs), and XD-grade carbon nanotubes (XD-CNTs) were dispersed in a vinyl ester (VE) resin using an ultrasonic probe at a fixed frequency. SWNTs were functionalized with succinic acid peroxide (SAP) to enhance dispersion. Increasing ultrasonication energy was found to improve the distribution of carbon nanotubes (CNTs) and decrease the size of ropes, whereas excessive amounts of energy were found to result in damage. The quality of dispersion was verified through optical microscopy and scanning electron microscopy (SEM).

Dielectrophoresis-Based Assembly and High-Frequency Characterization of Carbon Nanotube Bundles

2007 ◽  
Vol 990 ◽  
Author(s):  
Michael Woodson ◽  
Alexander Tselev ◽  
Jie Liu
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electrical Properties ◽  
Electronic Properties ◽  
Integrated Circuit ◽  
High Frequency ◽  
Simple Route ◽  
Full Characterization ◽  
Nanotube Bundles

ABSTRACTAs the size of integrated circuit elements decreases, the properties of carbon nanotubes (CNTs) become increasingly attractive for interconnect applications. To be used by industry, full characterization of the electronic properties of CNT aggregates is essential.Dielectrophoresis from CNTs suspended in liquid has been demonstrated as a simple route to bundles of aligned parallel nanotubes. We describe a method by which circuits including such bundles may be fabricated, and provide some high-frequency measurements of their electrical properties. The contributions of the contacts can be separated from those of the bundle itself.

Preparation and characterization of polyvinyl alcohol/carbon nanotube (PVA/CNT) conductive nanofibers

2012 ◽  
Vol 32 (6-7) ◽  
pp. 407-413 ◽  
Author(s):  
Ozcan Koysuren
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Polyvinyl Alcohol ◽  
Specific Capacitance ◽  
Electrode Surface ◽  
Electrospinning Process ◽  
Morphology Analysis ◽  
Highly Porous

Abstract The aim of this study was to prepare polyvinyl alcohol/carbon nanotube (PVA/CNT) conductive nanofibers by the electrospinning process. Prior to composite preparation, carbon nanotubes are dispersed homogeneously in N-methyl-2-pyrrolidone (NMP) and mixed with a PVA solution. A series of PVA/CNT films and nanofibers with various CNT compositions are prepared. Electrical conductivity and specific capacitance of spin-coated PVA/CNT films and electrospun PVA/CNT fibers increase with an increase in CNT content. Electrospun PVA/CNT nanofibers with a larger electrode surface result in a higher specific capacitance when compared with spin-coated PVA/CNT films. According to the morphology analysis, homogeneous and highly porous PVA/CNT mats containing 50–300 nm diameter nanofibers are obtained by the electrospinning process.

scholarly journals Carbon Nanotube (CNTs): Structure, Synthesis, Purification, Functionalisation, Pharmacology, Toxicology, Biodegradation and Application as Nanomedicine and Biosensor

2021 ◽  
Vol 001 (02) ◽  
Author(s):  
Jayendrakumar Patel ◽  
Shalin Parikh ◽  
Shwetaben Patel ◽  
Ronak Patel ◽  
Payalben Patel
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Surface Area ◽  
Carbon Nanostructures ◽  
The Body ◽  
Technological Advancement ◽  
Aggregation State ◽  
Wide Range ◽  
Biomedical Fields

It is well acknowledged that carbon nanotubes (CNTs) are a potential new class of nanomaterials for technological advancement. The recent discovery of diverse kinds of carbon nanostructures has sparked interest in the potential applications of these materials in a variety of disciplines. Numerous distinct carbon nanotube (CNT) production methods have been developed, and their characterisation, separation, and manipulation of individual CNTs are now possible. Structure, surface area, surface charge, size distribution, surface chemistry, aggregation state, and purity of the samples all have a significant impact on the reactivity of carbon nanotubes, as does the purity of the samples. Currently, carbon nanotubes (CNTs) are being successfully used in the medicinal, pharmaceutical, and biomedical fields because of their large surface area, which makes them capable of adsorbing or conjugating with a wide range of therapeutic and diagnostic substances (drugs, genes, vaccines, antibodies, biosensors, etc.). They were the first to demonstrate that they are a great vehicle for drug delivery straight into cells without the need for metabolic processing by the body. This paper discusses the different types, structures, and properties of CNTs, as well as CNT synthesis and purification methods, how to functionalize CNTs, and their application in medicinal, pharmaceutical, and biomedical fields, toxicological properties and their assessment, as well as in-vivo pharmacology and biodegradation pathways.

Characterization of air plasma-activated carbon nanotube electrodes for the removal of lead ion

2014 ◽  
Vol 69 (11) ◽  
pp. 2272-2278 ◽  
Author(s):  
Lingfang Yang ◽  
Zhou Shi ◽  
Wenhao Yang
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Carbon Nanotube ◽  
Lead Ion ◽  
Air Plasma ◽  
Surface Functional Groups ◽  
Plasma Activation ◽  
Scanning Electron

Carbon nanotube electrodes were prepared by pressing a mixture of carbon nanotubes and polytetrafluoroethylene (which acted as a binder) on a stainless steel net collector, and the electrodes were subsequently activated in our self-designed plasma apparatus, using air plasma. The morphology and surface functional groups of the electrodes were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The results showed that the electrodes activated by air plasma possessed a rougher surface and more oxygen-containing groups than the raw electrodes, properties that were beneficial for their electrosorption performance. After 5 min of air plasma activation, the lead ion electrosorption capacity of the activated electrodes (measured at 450 mV) increased to 3.40 mg/g, which was 73% higher than the capacity of the non-activated, raw electrode, and 5.76 times the adsorption capacity of the raw electrode at 0 mV. The results of this study indicate that air plasma activation can be used to effectively enhance the electrosorption capacity of carbon nanotube electrodes.

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