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Vertically aligned carbon nanotubes

Saeideh Tasharrofi, Hossein Taghdisian, Abdollah Golchoobi
In this study, pure and ternary adsorption of hydrogen sulfide (H2 S), ethylbenzene (EB), and carbon monoxide (CO) on different arrays of zigzag double wall carbon nanotube was investigated using grand canonical Monte Carlo simulations. The internal diameters of nanotube were fixed at 2r = 50.17 Å while nanotube wall distances were different values from d = 0 Å to d = 150 Å. Pure simulation results indicated that adsorption quantity of H2 S and EB in low pressure ranges of P = 1.9 bar to P = 3...
March 2, 2018: Journal of Molecular Graphics & Modelling
Jiadong Sheng, Shenglin Zhou, Zhaohui Yang, Xiaohua Zhang
We investigate the effect of the presence of vertically aligned multiwalled carbon nanotubes (CNT) on the orientation of poly(ethylene oxide)(PEO) lamellae and PEO crystallinity. The high alignment of carbon nanotubes acting as templates probably governs the orientation of PEO lamellae. This templating effect might results in the lamella planes of PEO crystals oriented along a direction parallel to the long axis of nanotubes. The presence of aligned carbon nanotubes also gives rise to the decreases in PEO crystallinity, crystallization temperature and melting temperature due to the perturbation of carbon nanotubes to the crystallization of PEO...
March 5, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Lin Jing, Hongling Li, Jinjun Lin, Roland Yingjie Tay, Siu Hon Tsang, Edwin Hang Tong Teo, Alfred Iing Yoong Tok
Vertically aligned carbon nanotube (CNT) arrays have been recognized as promising cushion materials because of their superior thermal stability, remarkable compressibility and viscoelastic characteristics. However, most of the previously reported CNT arrays still suffer from permanent shape deformation at only moderate compressive strains, which considerably restricts their practical applications. Here, we demonstrate a facile strategy of fabricating super-compressible coaxial CNT@graphene (CNT@Gr) arrays by using a two-step route involving encapsulating polymer layers onto plastic CNT arrays and subsequent annealing processes...
February 28, 2018: ACS Applied Materials & Interfaces
Qi Zhu, Xietao Yuan, Yihao Zhu, Jiangfeng Ni, Xiaohua Zhang, Zhaohui Yang
In this paper we fabricate a robust flexible solid-state supercapacitor (FSC) device by embedding a conductive poly (vinyl alcohol) hydrogel into the ACNT arrays. We carefully investigate the distribution, interface and densification effect on the electrochemical properties of CNTs in the gel matrix. A total electrochemical capacitance of the device is measured to be 227 mF·cm-3 with the maximum energy density of 0.02 mW·h·cm-3, which is dramatically enhanced compared to the similar device composed of unparallel CNTs...
February 21, 2018: Nanotechnology
T V Raziman, J A Duenas, W I Milne, O J F Martin, P Dawson
The D- and G-band Raman signals from random arrays of vertically aligned, multi-walled carbon nanotubes are significantly enhanced (up to ∼14×) while the signal from the underlying Si substrate is simultaneously attenuated (up to ∼6×) when the nanotubes are dressed, either capped or coated, with Ag. These Ag-induced counter-changes originate with the difference in geometry of the nanotubes and planar Si substrate and contrast in the Ag depositions on the substrate (essentially thin film) and the nanotube (nano-particulate)...
February 7, 2018: Physical Chemistry Chemical Physics: PCCP
Ramonita Díaz-Ayala, Lisa Torres-González, Ruth Pietri, Carlos R Cabrera, Juan López-Garriga
The recombinant HbI was fused with a poly-Lys tag ((Lys)6-tagged rHbI) for specific-site covalent immobilization on two carbon nanotube transducer surfaces, i.e., powder and vertically aligned carbon nanotubes. The immobilization was achieved by following two steps: (1) generation of amine-reactive ester from the carboxylic acid groups of the surfaces and (2) coupling these groups with the amine groups of the Lys-tag. We analyzed the immobilization process using different conditions and techniques to differentiate protein covalent attachment from physical adsorption...
December 31, 2017: ACS Omega
Noemí Aguiló-Aguayo, Roger Amade, Shahzad Hussain, Enric Bertran, Thomas Bechtold
New three-dimensional (3D) porous electrode concepts are required to overcome limitations in Li-ion batteries in terms of morphology (e.g., shapes, dimensions), mechanical stability (e.g., flexibility, high electroactive mass loadings), and electrochemical performance (e.g., low volumetric energy densities and rate capabilities). Here a new electrode concept is introduced based on the direct growth of vertically-aligned carbon nanotubes (VA-CNTs) on embroidered Cu current collectors. The direct growth of VA-CNTs was achieved by plasma-enhanced chemical vapor deposition (PECVD), and there was no application of any post-treatment or cleaning procedure...
December 11, 2017: Nanomaterials
Xining Zang, Caiwei Shen, Emmeline Kao, Roseanne Warren, Ruopeng Zhang, Kwok Siong Teh, Junwen Zhong, Minsong Wei, Buxuan Li, Yao Chu, Mohan Sanghadasa, Adam Schwartzberg, Liwei Lin
While electrochemical supercapacitors often show high power density and long operation lifetimes, they are plagued by limited energy density. Pseudocapacitive materials, in contrast, operate by fast surface redox reactions and are shown to enhance energy storage of supercapacitors. Furthermore, several reported systems exhibit high capacitance but restricted electrochemical voltage windows, usually no more than 1 V in aqueous electrolytes. Here, it is demonstrated that vertically aligned carbon nanotubes (VACNTs) with uniformly coated, pseudocapacitive titanium disulfide (TiS2 ) composite electrodes can extend the stable working range to over 3 V to achieve a high capacitance of 195 F g-1 in an Li-rich electrolyte...
February 2018: Advanced Materials
O Pitkänen, T Järvinen, H Cheng, G S Lorite, A Dombovari, L Rieppo, S Talapatra, H M Duong, G Tóth, K L Juhász, Z Kónya, A Kukovecz, P M Ajayan, R Vajtai, K Kordás
On-chip energy storage and management will have transformative impacts in developing advanced electronic platforms with built-in energy needs for operation of integrated circuits driving a microprocessor. Though success in growing stand-alone energy storage elements such as electrochemical capacitors (super and pseusocapacitors) on a variety of substrates is a promising step towards this direction. In this work, on-chip energy storage is demonstrated using architectures of highly aligned vertical carbon nanotubes (CNTs) acting as supercapacitors, capable of providing large device capacitances...
November 29, 2017: Scientific Reports
Federica Bondino, Elena Magnano, Regina Ciancio, Carla Castellarin Cudia, Alessandro Barla, Elvio Carlino, Flora Yakhou-Harris, Nalin Rupesinghe, Cinzia Cepek
Well-defined sized (5-10 nm) metallic iron nanoparticles (NPs) with body-centered cubic structure encapsulated inside the tip of millimeter-long vertically aligned carbon nanotubes (VACNTs) of uniform length have been investigated with high-resolution transmission electron microscopy and soft X-ray spectroscopy techniques. Surface-sensitive and chemically-selective measurements have been used to evaluate the magnetic properties of the encapsulated NPs. The encapsulated Fe NPs display magnetic remanence up to room temperature, low coercivity, high chemical stability and no significant anisotropy...
December 6, 2017: Physical Chemistry Chemical Physics: PCCP
E M Akinoglu, K Ozbilgin, P Kilicaslan Sonmez, M M Ozkut, M Giersig, S Inan, E Gumustepe, C Kurtman
The aim of the current study was to determine whether the MWCNT-based scaffold has a suitable structure for cell growth and provides a biocompatible environment for human MDA-MB-231 cell lines. MWCNT-based nanostructured scaffolds were produced by plasma-enhanced chemical vapor deposition (PECVD) technique. MDA-MB-231 cells were seeded on MWCNTs-textured silicon scaffolds and on pristine silicon surfaces. After 1 week of culturing, the scaffolds were prepared for SEM analysis and immunocytochemical staining was performed for the two groups (MWCNT scaffold and pristine silicon surface), using MMP-2, MMP-9, PI3K, AKT and NF-κB primary antibodies...
December 2017: Progress in Biomaterials
Hossein Sojoudi, Sanha Kim, Hangbo Zhao, Rama Kishore Annavarapu, Dhanushkodi Mariappan, A John Hart, Gareth H McKinley, Karen K Gleason
Scalable manufacturing of structured materials with engineered nanoporosity is critical for applications in energy storage devices (i.e., batteries and supercapacitors) and in the wettability control of surfaces (i.e., superhydrophobic and superomniphobic surfaces). Patterns formed in arrays of vertically aligned carbon nanotubes (VA-CNTs) have been extensively studied for these applications. However, the as-deposited features are often undesirably altered upon liquid infiltration and evaporation because of capillarity-driven aggregation of low density CNT forests...
December 13, 2017: ACS Applied Materials & Interfaces
Seyed Mohsen Hosseini, Vahid Pirouzfar, Hamed Azami
In the present work, vertically aligned carbon nanotube (VA-CNT) sheets were synthesized via pyrolysis of polybenzimidazole (PBI)-Kapton inside the pores of anodized aluminum oxide (AAO). The synthesized VA-CNT sheets were then evaluated for the desalination of salty water. The results indicated that the VA-CNT sheets were effective for application as an adsorbent for desalination of salty water due to their high adsorption capacity, with no loss of CNTs in the treated water. This study explored the impact of operating time and temperature on liquid adsorption performance through optimization and modeling methods...
December 2017: Journal of Membrane Biology
Sagar Motilal Jain, Federico Cesano, Domenica Scarano, Tomas Edvinsson
Carbon nanotubes (CNTs) are considered promising for a large range of emerging technologies ranging from advanced electronics to utilization as nanoreactors. Here we report a controlled facile synthesis of aligned carbon nanotubes with very small dimensions directly grown on steel grid substrates via two-step catalytic chemical vapor deposition (CCVD) of a molecular catalyst (ferrocene) with ethylene as the carbon source. The system is characterized by resonance Raman spectroscopy and the results show single walled carbon nanotube (SWCNT) arrays composed of 0...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
Junjun Ding, Shichen Fu, Runzhi Zhang, Eric Boon, Woo Lee, Frank T Fisher, Eui-Hyeok Yang
Stretchable electrodes are a critical component for flexible electronics such as displays, energy devices, and wearable sensors. Carbon nanotubes (CNTs) and graphene have been considered for flexible electrode applications, due to their mechanical strength, high carrier mobility, and excellent thermal conductivity. Vertically aligned carbon nanotubes (VACNTs) provide the possibility to serve as interconnects to graphene sheets as stretchable electrodes that could maintain high electrical conductivity under large tensile strain...
October 24, 2017: Nanotechnology
Qi Ming Zou, Lei Min Deng, Da Wei Li, Yun Shen Zhou, Hossein Rabiee Golgir, Kamran Keramatnejad, Li Sha Fan, Lan Jiang, Jean-Francois Silvain, Yong Feng Lu
Traditional ceramic-based, high-temperature electrode materials (e.g., lanthanum chromate) are severely limited due to their conditional electrical conductivity and poor stability under harsh circumstances. Advanced composite structures based on vertically aligned carbon nanotubes (VACNTs) and high-temperature ceramics are expected to address this grand challenge, in which ceramic serves as a shielding layer protecting the VACNTs from the oxidation and erosive environment, while the VACNTs work as a conductor...
October 12, 2017: ACS Applied Materials & Interfaces
Divya Puthusseri, Deepu J Babu, Sherif Okeil, Jörg J Schneider
Whereas vertically aligned carbon nanotubes (VACNTs) typically show a promising adsorption behavior at high pressures, carbon nanohorns (CNHs) exhibit superior gas adsorption properties in the low pressure regime due to their inherent microporosity. These adsorption characteristics are further enhanced when both materials are opened at their tips. The so prepared composite material allows one to investigate the effect of physical entrapment of CO2 molecules within the specific adsorption sites of VACNTs composed of opened double walled carbon nanotubes (CNTs) and in specific adsorption sites created by spherically aggregated opened single walled carbon nanohorns...
October 4, 2017: Physical Chemistry Chemical Physics: PCCP
Claudia Struzzi, Mattia Scardamaglia, Jean-François Colomer, Alberto Verdini, Luca Floreano, Rony Snyders, Carla Bittencourt
The surface chemistry of plasma fluorinated vertically aligned carbon nanotubes (vCNT) is correlated to the CF4 plasma chemical composition. The results obtained via FTIR and mass spectrometry are combined with the XPS and Raman analysis of the sample surface showing the dependence on different plasma parameters (power, time and distance from the plasma region) on the resulting fluorination. Photoemission and absorption spectroscopies are used to investigate the evolution of the electronic properties as a function of the fluorine content at the vCNT surface...
2017: Beilstein Journal of Nanotechnology
Junjun Ding, Shichen Fu, Runzhi Zhang, Eric Peter Boon, Woo Lee, Frank T Fisher, Eui-Hyeok Yang
Stretchable electrodes are a critical component for flexible electronics such as displays, energy devices, and wearable sensors. Carbon nanotubes (CNTs) and graphene have been considered for flexible electrode applications, due to their mechanical strength, high carrier mobility, and excellent thermal conductivity. Vertically aligned carbon nanotubes (VACNTs) provide the possibility to serve as interconnects to graphene sheets as stretchable electrodes that could maintain high electrical conductivity under large tensile strain...
September 11, 2017: Nanotechnology
Anna Szabó, Egon Kecsenovity, Zsuzsanna Pápa, Tamás Gyulavári, Krisztián Németh, Endre Horvath, Klara Hernadi
In the past two decades, important results have been achieved in the field of carbon nanotube (CNT) research, which revealed that carbon nanotubes have extremely good electrical and mechanical properties The range of applications widens more, if CNTs form a forest-like, vertically aligned structure (VACNT) Although, VACNT-conductive substrate structure could be very advantageous for various applications, to produce proper system without barrier films i.e. with good electrical contact is still a challenge. The aim of the current work is to develop a cheap and easy method for growing carbon nanotubes forests on conductive substrate with the CCVD (Catalytic Chemical Vapor Deposition) technique at 640 °C...
August 25, 2017: Scientific Reports
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