Single-walled Carbon Research Articles

Single-walled carbon nanotubes-G-quadruple hydrogel nanocomposite matrixes for cell support applications.

Single-walled carbon nanotubes-G-quadruple hydrogel nanocomposite matrixes for cell support applications.

Single-walled carbon nanotubes/Ni–Co–Mn layered double hydroxide nanohybrids as electrode materials for high-performance hybrid energy storage devices

Nanohybrids which combine SWCNTs and Ni–Co–Mn layered double hydroxides are prepared by a facile hydrothermal process and investigated for the first time as electrode materials for hybrid energy storage devices. The nanohybrid made with a precursor weight ratio of SWCNTs and Ni–Co–Mn layered double hydroxide of 10:90 exhibits the highest capacity of 912 C g−1 at 1 A g−1, while the nanohybrid made with a precursor weight ratio of 30:70 shows the highest rate retention of 65% from 1 A g−1 (672 C g−1) to 50 A g−1 (435 C g−1) and the best capacity retention of 70% after 10000 cycles. Moreover, the charge transfer mechanism of the Ni–Co–Mn layered double hydroxides during charge/discharge is investigated through in-situ X-ray absorption near-edge spectra. To demonstrate practical hybrid energy storage applications, two nanohybrid//SWCNTs asymmetric energy storage devices are assembled and tested in pouch cell configuration. Their performances under folded condition are also evaluated, revealing great potential for flexible hybrid energy storage applications.

Simultaneous Sensing of Touch and Pressure by Using Highly Elastic e-Fabrics

In recent years, electronic skins have been widely studied for human monitoring systems. This research field needs multi-sensing points for large deformation, strong recovery, and mass production methods. Toward these aims, the fabrication of e-fabric skins made from a capacitive touch sensing layer and a capacitive pressure sensing layer is presented in the paper. Due to the high elasticity of the dielectric layer of the spacer fabric, this structure exhibits a very fast recovery time (6 ms), low hysteresis (<5%), and high cycling stability (>20,000 times). Besides, the stacking structure of the electrode layers ( single-wall carbon nanotube/silver paste) is due to good durability even under large deformations (grasping, bending, stretching), and the skin is breathable for applications. As expected, the e-fabric skin is proven to be robust for detecting a spatial pressure distribution in real time. The extremely simple fabrication process is also an extra plus point in view of point mass production.

Dramatic efficiency boost of single-walled carbon nanotube-silicon hybrid solar cells through exposure to ppm nitrogen dioxide in air: An ab-initio assessment of the measured device performances

We observed a 73% enhancement of the power conversion efficiency (PCE) of a photovoltaic cell based on a single wall carbon nanotube/Si hybrid junction after exposing the device to a limited amount (10 ppm) of NO2 diluted in dry air. On the basis of a computational modeling of the junction, this enhancement is discussed in terms of both carbon nanotube (CNT) p-doping, induced by the interaction with the oxidizing molecules, and work function changes across the junction. Unlike studies so far reported, where the PCE enhancement was correlated only qualitatively to CNT doping, our study (i) provides a novel and reversible path to tune and considerably enhance the cell efficiency by a few ppm gas exposure, and (ii) shows computational results that quantitatively relate the observed effects to the electrostatics of the cell through a systematic calculation of the work function. These effects have been cross-checked by exposing the cell to reducing molecules (i.e·NH3) that resulted to be detrimental to the cell efficiency, consistently with the theoretical ab-initio calculations.

Controlling Electrode Spacing by Polystyrene Microsphere Spacers for Highly Stable and Flexible Transparent Supercapacitors.

Transparent polymer electrolytes such as poly(vinyl alcohol)-based H+, Li+, K+, and Na+ gels have been widely used as both an electrolyte and a separator for flexible transparent supercapacitors (FTSCs). However, these gels sandwiched between the electrodes in FTSCs are easily compressed under bending and compression due to their viscous flow behavior, resulting in the deformation of electrode spacing and the unstable capacitance performance. To resolve this issue, herein, we introduce monodispersed polystyrene (PS) microspheres into PVA-LiCl polymer gel electrolytes as spacers to precisely control the electrode spacing during the assembly of FTSCs using single-walled carbon nanotubes/indium tin oxide-polyethylene terephthalate (ITO-PET) or MnO2/multiwalled carbon nanotubes/ITO-PET as transparent electrodes. The electrode spacing could be tuned by varying the diameter of PS microspheres, for example, 20, 40, and 80 μm. More importantly, the PS microsphere spacers protect the gel electrolyte from the squeeze when bending takes place, allowing the stable performance output by FTSCs under a bending state. After repeating bending tests, the capacitance remains 95.6%, indicating the high stability and flexibility of the devices with the assistance of PS microsphere spacers.

Dry Sliding Friction Analysis and Wear Behavior of Carbon Nanotubes / Vinylester Nanocomposites, Using Pin-on-Disc Test

Dry sliding friction and wear behavior of single-wall (SW) and multi-wall (MW) carbon nanotubes (CNTs)/ vinylester composite have been investigated, under several loads and sliding speeds. Three different contents (0.1, 0.15 and 0.2 wt. %) of SWCNT and MWCNTs have been dispersed into the vinylester resin in order to obtain polymer nanocomposites. The present study discusses the coefficient of friction, specific wear rate and friction stability of vinylester composites with different CNTs content, using a pin-on-disc test. The friction and wear experiments were carried out following 3 loads×3 speeds, as test parameters. The best combination of friction and wear properties was found with the nanocomposite containing 0.2 wt.% MWCNT. Keywords: carbon nanotubes, vinylester, friction, wear

Application of A Novel, Non-Doped, Organic Hole-Transport Layer into Single-Walled Carbon Nanotube/Silicon Heterojunction Solar Cells

The search for novel solar cell designs as an alternative to standard silicon solar cells is important for the future of renewable energy production. One such alternative design is the carbon nanotube/silicon (CNT/Si) heterojunction solar device. In order to improve the performance of large area CNT/Si heterojunction solar cells, a novel organic material, 4,10-bis(bis(4-methoxyphenyl)amino)naptho[7,8,1,2,3-nopqr]tetraphene-6,12-dione (DPA-ANT-DPA (shortened to DAD)), was added as an interlayer between the CNT film and the silicon surface. The interlayer was examined with SEM and AFM imaging to determine an optimal thickness for solar cell performance. The DAD was shown to improve the device performance with the efficiency of large area devices improving from 2.89% ± 0.40% to 3.34% ± 0.10%.

بررسی کارآیی نانولوله‌های کربنی تک‌دیواره و چند دیواره در حذف داروی استامینوفن از محیط‌های آبی:مطالعه ایزوترم و سینتیک جذب

بررسی کارآیی نانولوله‌های کربنی تک‌دیواره و چند دیواره در حذف داروی استامینوفن از محیط‌های آبی:مطالعه ایزوترم و سینتیک جذب

Label-Free Electrochemical Detection of DNA Hybridization Related to Anthrax Lethal Factor by using Carbon Nanotube Modified Sensors

Background: Anthrax Lethal Factor (ANT) is the dominant virulence factor produced by B. anthracis and is the major cause of death of infected animals. In this paper, pencil graphite electrodes GE were modified with single-walled and multi-walled carbon nanotubes (CNTs) for the detection of hybridization related to the ANT DNA for the first time in the literature. Methods: The electrochemical monitoring of label-free DNA hybridization related to ANT DNA was explored using both SCNT and MCNT modified PGEs with differential pulse voltammetry (DPV). The performance characteristics of ANT-DNA hybridization on disposable GEs were explored by measuring the guanine signal in terms of optimum analytical conditions; the concentration of SCNT and MCNT, the concentrations of probe and target, and also the hybridization time. Under the optimum conditions, the selectivity of probe modified electrodes was tested and the detection limit was calculated. Results: The selectivity of ANT probes immobilized onto MCNT-GEs was tested in the presence of hybridization of probe with NC no response was observed and with MM, smaller responses were observed in comparison to full-match DNA hybridization case. Even though there are unwanted substituents in the mixture samples containing both the target and NC in the ratio 1:1 and both the target and MM in the ratio 1:1, it has been found that ANT probe immobilized CNT modified graphite sensor can also select its target by resulting with 20.9% decreased response in comparison to the one measured in the case of full-match DNA hybridization case Therefore, it was concluded that the detection of direct DNA hybridization was performed by using MCNT-GEs with an acceptable selectivity. Conclusion: Disposable SCNT/MCNT modified GEs bring some important advantages to our assay including easy use, cost-effectiveness and giving a response in a shorter time compared to unmodified PGE, carbon paste electrode and glassy carbon electrode developed for electrochemical monitoring of DNA hybridization. Consequently, the detection of DNA hybridization related to the ANT DNA by MCNT modified sensors was performed by using lower CNT, probe and target concentrations, in a shorter hybridization time and resulting in a lower detection limit according to the SCNT modified sensors. In conclusion, MCNT modified sensors can yield the possibilities leading to the development of nucleic acid sensors platforms for the improvement of fast and cost-effective detection systems with respect to DNA chip technology.

Significance of Velocity Slip in Convective Flow of Carbon Nanotubes

The present article inspects velocity slip impacts in three-dimensional flow of water based carbon nanotubes because of a stretchable rotating disk. Nanoparticles like single and multi walled carbon nanotubes (CNTs) are utilized. Graphical outcomes have been acquired for both single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). The heat transport system is examined in the presence of thermal convective condition. Proper variables lead to a strong nonlinear standard differential framework. The associated nonlinear framework has been tackled by an optimal homotopic strategy. Diagrams have been plotted so as to examine how the temperature and velocities are influenced by different physical variables. The coefficients of skin friction and Nusselt number have been exhibited graphically. Our results indicate that the skin friction coefficient and Nusselt number are enhanced for larger values of nanoparticle volume fraction.

High performance p-type organic thermoelectric materials based on metalloporphyrin/single-walled carbon nanotube composite films

Single-walled carbon nanotube/organic small molecule based thermoelectric materials have attracted significant scientific attention in recent years. However, up to now, no detailed thermoelectric study reported is focused on the single-walled carbon nanotube/organometallic complex composite films. By considering the excellent properties of tetraphenylporphyrin (such as its π-conjugated system, versatile structure and stability) and the important roles of metal ions in improving thermoelectric properties, metalloporphyrins manifest great potential as composites for single-walled carbon nanotubes. Hence, in this work, we first propose a convenient strategy to obtain high-performance thermoelectric composites containing metalloporphyrin molecules and single-walled carbon nanotubes. It is found that the single-walled carbon nanotube/ZnTPP composite film demonstrates the best thermoelectric performance with a maximum power factor of 247.2 μWm−1K−2 at 340 K, which is perhaps one of the highest thermoelectric power factors reported for single-walled carbon nanotube/organic small molecule-based p-type materials. Three p-type materials exhibit outstanding electric conductivities with a maximum of 1028.7 S cm−1 (single-walled carbon nanotube/CuTPP at 340 K). Furthermore, the produced thermoelectric materials manifest outstanding air stability and thermostability. Therefore, our proposed method can be a promising reference for fabricating novel p-type high-performance thermoelectric materials using metalloporphyrin-based building blocks.

Heat transfer analysis of armchair (5, 5) and zigzag (10, 0) carbon nanotubes

The technological interest for a given material depends very much on its thermal properties. The carbon nanotubes forming atoms a circular structure with a diameter of the order of 1 nm, but with a length which can be up to several hundred microns. This makes the carbon nanotubes to form an excellent model for one-dimensional systems. Much research has been devoted to the manufacture of carbon nanotubes, which are expected to represent the material that will be included in the next generation of heat exchangers components. Despite all the attention that carbon nanotubes have attracted from a scientific perspective, the theoretical understanding of them only developed relatively limited. Stability and performance of nano-device control plays a critical role in the heat conduction of nanotubes. Carbon nanotubes are one-atom thick as small-sized materials are excellent conductors of heat. In this context, in the present study by the method of finite element mesh based thermal behavior of carbon nanotubes are examined. In this study the lattice thermal conductivity of nanotubes is to see the effect. Single-walled and multiwalled carbon nanotubes in the ANSYS simulation technique has been developed and implemented. This method is different in the lattice of the nanotubes was used to compare the heat conduction. The number of bonds is equal to the number of atoms and nanotubes are modeled. Lattice structure which is different armchair (5, 5) and zigzag (10, 0) nanotube thermal conductivity, were compared. The results presented, the proposed finite element model, to study the thermal behavior of carbon nanotubes, have shown an important method.

Frost-Resistant Elastomeric Nanocomposites for Operation in the Far North Conditions

Operation of elastomeric materials in the extreme climatic conditions of the North is a complex and expensive, since not always existing materials can provide the required level of low-temperature characteristics (down to-60 ° C). This leads to failure of machines and mechanisms, equipment downtime, additional costs for repair or replacement of rubber parts. The need for such materials is continuously growing due to the intensive development of the northern territories, the need to develop new mineral deposits and development of offshore hydrocarbon production. Propylene oxide rubber (Tg = -73 °С) and epichlorohydrin rubber Hydrin T6000 (Tg = -60 °С) have unique frost resistance, but there is a need to improve aggressive media resistance, wear resistance and relaxation properties (the ability to restore its shape after relieving the load). For the modification of rubbers, additives of both organic and inorganic nature were chosen: ultrafine polytetrafluoroethylene, single-walled and multi-walled carbon nanotubes, nanodiamond-containing carbon charge obtained by detonation synthesis, shungite, natural zeolites and bentonite clays. The operating properties of rubber were studied in accordance with standard methods. The structure of the obtained materials was studied by means of DSC, XRD, electron and atomic force microscopy. All developed materials are recommended for use in various industries (oil and gas, road, rail) in the Arctic regions with extreme climatic conditions.

Effects of short-time plasma treatment in the magnetron sputtering equipment on various carbon nanotubes for applied to LCD backlight unit

The field emission and luminescent properties of various (single-walled CNTs, double-walled CNTs, multi-walled CNTs, and carbon nanofibers) screen-printed carbon nanotubes (SP-CNTs) that were straightened using plasma treatment in the magnetron sputtering equipment (MSE) for a short time were investigated. The SP-CNTs investigated CNT field emitter arrays for back light unit (BLU) in liquid crystal display (LCD). The plasma treatment in the MSE enhanced the emission properties of the single-walled CNTs (SWCNTs) and double-walled CNTs (DWCNTs): the emission uniformity and number of emission sites increased. Recurring problems associated with SW and DW SP-CNTs such as bent and/or buried CNTs and degradation of binder–residue-induced emission were ameliorated by inducing protrusion from the binder and permanent straightening of the SW and DW SP-CNTs as a result of treatment. The multi-walled CNTs (MWCNTs) and carbon nanofibers (CNFs) had partial emission sites with poor emission factors. The results of the present study suggest that plasma treatment in the MSE of SW and DW SP-CNTs is an effective method for achieving uniform field emission and reducing the aging.

Single-Walled Carbon Nanotubes/Poly Vinyl Chloride Nanocomposites and its Properties

The SWNTs was purified/functionalized by acid treatment method and the F-SWNTs were used as reinforcing materials. The acid treatment introduced carboxyl (–COOH) group to the SWNTs. The PVC and F-SWNTs/PVC films were prepared by solution casting method. The fractured surfaces of sample was analyzed through SEM and showed the dispersion of F-SWNTs in PVC. The thermal study indicated that the thermal stability of PVC is enhanced with F-SWNTs incorporation. The mechanical properties were also increased with CNTs filling. The solvent uptake study suggested that the nanocomposites resist towards solvent uptake, which is due to the hydrophobic nature of CNTs and their irregular network formation within the polymer matrix. Keywords: Polyvinyl chloride, single walled carbon nanotubes, morphology, nanocomposite

Do carbon nanotubes inhibit or promote amyloid fibrils formation?

Objectives: The purpose of the work was to study the effect of carbon nanotubes on the formation of fibril structures in lysozyme at room temperature under different pH values. Materials and methods: For the preparation of the samples, hen egg-white lysozyme protein (HEWL, Fluka), as well as single-walled (SWCNT, Sigma-Aldrich) and multi-walled (MWCNT, OOO TM “Spetsmash”, Kyiv, Ukraine) carbon nanotubes were used. Used techniques: IR-Fourier Absorption Spectroscopy; confocal microscopy. Results: In this paper, the study of molecular mechanisms of interaction of lysozyme with carbon nanotubes by vibrational spectroscopy was carried out and a conformational analysis of the formed complexes was performed. It is shown that carbon nanotubes can affect the structure of lysozyme even at room temperature and normal pH values, as evidenced by conformational changes in lysozyme due to interaction with carbon nanotubes. Complexes which are formed as a result of such interaction, have characteristic features of amyloid fibrillar structures. It reveals one of possible mechanisms of carbon nanotubes cytotoxicity. On the other hand, such a technique can be introduced to obtain model amyloid fibrils for further study. Conclusion: The method of vibtarional spectroscopy has shown that carbon nanotubes can influence the structure of lysozyme, as it is shown by the conformational analysis of the absorption band Amide I. After the interaction of lysozyme with CNT, an increase in the contribution of antiparallel β-conformation in the structure of lysozyme is observed, and the contribution of the α-helix conformation is reduced, which are characteristic features in the formation of fibrillar structures. The possibility of amyloid fibril formation without the use of high temperatures at different pH values with the interaction of lysozyme and carbon nanotubes, which can be applied as a method for obtaining the model amyloid fibrils, is shown.

Phytotoxicity of carbon nanotubes and nanodiamond in long-term assays with Cactaceae plant seedlings

We present the results of long-term phytotoxicity assays of single-walled and multi-walled carbon nanotubes (SWNTs and MWNTs, respectively) and nanodiamond (ND) employing cactus species Ferocactus latispinus, Melocactus matanzanus and Parodia ayopayana. They are small and slow growing plants, which is convenient for long-term assays using the substrate volumes as small as a few milliliters, contrary to the commonly reported experiments with crop species. The soil-based experiments described allow for a better match of the real environmental situation. After a few months (up to 40 weeks) observations of seedling growth, we concluded that pristine arc-discharge SWNTs exhibit the strongest phytotoxic effect as compared to pristine MWNTs, purified SWNTs and ND, which can be attributed to a high amount of impurities (including remainders of the catalyst used for their synthesis) in as-prepared SWNTs. We found that after first three months of exposure, nanomaterials might produce seemingly favorable effect on seedling growth, which can invert after a more prolonged exposure. Therefore, careful evaluation of the possible phytotoxic effects must include observations for several months, whereas shorter assays might produce misleading results.

Evaluation of Frictional Characteristics of Nanoparticle Reinforced Arch wires and Brackets

The portion of the applied orthodontic force lost due to resistance to sliding can range from 12-60%. Hence high frictional force can affect the efficiency of treatment, resulting in increased treatment time and compromised treatment results because of loss of anchorage. To develop an ideal orthodontic system, the frictional characteristics between the arch wire-bracket needs to be understood. The purpose of this study was to evaluate the frictional characteristics of the single-walled and multi-walled carbon nanotube coated (SWCNT and MWCNT) arch wire and bracket. Method: 0.019×0.025-in SS arch wire and bracket was coated with SWCNT and MWCNT separately using Chemical Vapour Deposition (CVD) technique. The frictional values between the various combinations of arch wires and brackets were studied using Universal Friction Testing machine. Results: Combination of stainless-steel wire and multi-walled carbon nanotube coated bracket showed the least friction 0.18±0.06. Conclusion: With this different combination of bracket and arch wire we may be able to achieve the optimum levels of orthodontic forces in order to gain normal tooth movement.

Infrared and Raman active vibrational modes in MoS2 -based nanotubes: Symmetry analysis and first-principles calculations.

The possibility to use the axial point group dynamical representations for the infrared and Raman active modes classification in nanotubes is analyzed. The method proposed allows one to obtain the results of phonon symmetry analysis for nanotubes in Mulliken designations, which are traditional for molecules and crystallographic point groups. The approach suggested is applied to the phonon symmetry analysis in the single-wall carbon and MoS2 -based nanotubes. First-principles calculations of phonons in a bulk MoS2 crystal and a monolayer S-Mo-S are made. The results obtained are in reasonable agreement with the existing experimental data and other published results. The first-principles calculations of the phonon frequencies for armchair and zigzag MoS2 nanotubes are performed for the first time. It is shown that the number of infrared and Raman active modes becomes fixed starting from the relatively small nanotube diameters. The correlation of the phonon modes of MoS2 nanotubes with diameters up to 3.64 nm with phonon modes of the S-Mo-S monolayer is analyzed. It is demonstrated that the interpretation of the nature of nanotube A-type modes in the crystallographic factorization of the line group L = TF is the same as for m = 0 modes in the "polymer type" factorization L = ZP where P is the subgroup of the isogonal point group F, T is the translation subgroup of line group and the cyclic group Z includes the one-dimensional translations and the rotations around the screw axes or the reflections in the glide planes. © 2018 Wiley Periodicals, Inc.

Numerical study on magnetohydrodynic CNTs-water nanofluids as a micropolar dusty fluid influenced by non-linear thermal radiation and joule heating effect

Numerical study on magnetohydrodynic (MHD) flow and heat transfer of incompressible CNTs-water nanoparticles (single wall carbon and tube (SWCNT) and multiwall cabin nanotube (MWCNT)) as a non-Newtonian micropolar dusty fluid influenced by non-linear thermal radiation and joule heating effect over stretching plate are investigated in this paper. The governing equations have been solved by numerical method. Flow and heat transfer for two cases of prescribed heat flux (PHF) and prescribed surface temperature (PST) are analyzed, As a important result have been mentioned to the reduction of velocity profile due to the Lorentz force by increasing magnetic field parameter, the temperature profile increases by increasing radiation parameter, and MWCNT in comparison to the SWCNT has a greater effect on velocity profile also SWCNT in compared to the MWCNT has a greater effect on temperature profile and heat transfer.