Papers by Keyword: Carbon Nanotube (CN)

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Authors: Xiao Ying Lu, Hao Wang, Sheng Yi Xia, Jian Xin Wang, Jie Weng
Abstract: Carbon nanotubes (CNTs)/hydroxyapatite (HA) nanocomposites have been successfully fabricated by a novel method for the biomedical applications, which is in situ growing CNTs in HA matrix in a chemical vapor deposition (CVD) system. The results show that it is feasible to in situ grow CNTs in HA matrix by CVD for the fabrication of CNTs/HA nanocomposites. Multi-walled CNTs with 50-80 nm in diameter have been grown in situ from HA matrix with the pretreatment of sintering at 1473K in air. The nanocomposites are composed with carbon crystals in CNTs form, HA crystallites and calcium phosphate crystallites, one of most important CaP bioceramics. And the CNTs content is about 1% proportion by weight among the composites in our experiments, which can enhance the HA mechanical properties and the CNTs content does not affect the HA performances. These CNTs/HA nanocomposites have the potential application in the biomedical fields.
Authors: Jing Jing Liang, Zong Bin Zhao, Han Hu, Jie Shan Qiu
Abstract: This work presents a facile approach to grow carbon nanotubes (CNTs) on the surface of carbon foams (CFs) for the fabrication of hierarchical CNTs/CF composites, which exhibit enhanced oil adsorption capability. The preparation of CFs is carried out by using commercially available polyurethane (PU) foams as hard template and resol as carbon precursor. Fe/Mg/Al layered double hydroxide (LDHs) is used as catalyst precursor for the efficient growth of CNTs on CFs via chemical vapor deposition (CVD), in which CNTs are controllably grown onto the strut of CFs. The presence of CNTs in the CFs can significantly improve the hydrophobicity of the composites and enable the selective separation of oil from water with the combination of hydrophobicity and capillary action. Such well-designed hierarchical nanostructures are benefit for maximum utilization of cell structure and surface property of the composites and display good oil adsorption performance. The synthesis procedure paves the way for the exploitation of the CFs as adsorbent for the removal of spill oil and environmental protection.
Authors: Chihiro Iwamoto, Shunichiro Tanaka
Abstract: In-situ HRTEM technique was applied to various substrates and the reaction processes between substrates and molten alloy were compared. Substrates used were SiC, Si3N4, Si wafers, an amorphous carbon film, and a carbon nanotube. Ti-containing Ag-Cu eutectic alloy foil was placed on the substrate and the combined specimen mounted on the heating holder of an HRTEM and heated in the microscope to melt the alloy foil. In the case of SiC, Si3N4, carbon materials, the molten alloy spreading on the substrates were observed after melting of the alloy. SiC polar plane nano-steps appeared with the SiC dissociation by the molten alloy. On the surface of the carbon nanotube, thin film precursor spreading was observed. In contrast, Si reaction with the molten alloy produced big holes at the contacted area and molten alloy spreading was not observed.
Authors: Hai Hui Liu, Ning Wang, Li Chen Hou, Wei Wei Peng, Yan Mei Jin, Xing Xiang Zhang
Abstract: Pristine multi-walled carbon nanotubes (P-MWNTs) were functionalized with 4-substituted benzoic acid via ‘‘direct’’ Friedel-Crafts acylation in mild reaction medium of polyphosphoric acid (PPA)/phosphorous pentoxide (P2O5). Raman spectroscopy, thermogravimetric analysis, transmission electron microscopy were applied in this paper to demonstrate that multi-walled carbon nanotubes inherently have functional groups on their surfaces as a result of the reaction. The overall evidence indicates that the 4-substituted benzoic acid functionalization of carbon nanotube can be achieved without oxidation as pre-treatment. Thus, aryl carbonyl moieties with different length of 4-substituted alkyl acyl amine functionalized MWNTs(F-MWNTs) can be synthesized simply, without disrupting the primary structures of the nanotubes.
Authors: S.M. Kim, Hyun Kyu Kweon
Abstract: This study is about the underlying conjugation mechanism between carbon nanotube and biomolecule by molecular dynamics. In order to know about the conjugation mechanism between carbon nanotube and biomolecule, molecular dynamics simulation between carbon nanotube and water molecules was taken first and then molecular dynamics simulation between biomolecules and water molecules was taken. At simulation between carbon nanotube and water molecules, kinetic energy and potential energy became decreased with time and it means that the distance between carbon nanotube and water molecules becomes distant with time by van der Waals force and hydrophobic force. Simulation results between biomolecules and water molecules are also same as the results of carbon nanotube and water molecules simulation. From these two simulations, the conjugation mechanism between carbon nanotube and biomolecules can be predicted. Also, from simulation results between carbon nanotube and biomolecules, the distance between carbon nanotube and biomolecules becames close and it supports previous two simulation results. From these results, we can know that biomolecules enter into the carbon nanotube's cavity because of van der Waals force and hydrophobic force.
Authors: Mohd Afzan Mohd Anuar, Ahmad Azlan Mat Isa
Abstract: Carbon nanotubes (CNTs) are said to be among the most potential materials in applications of nanodevices, nanocomposites and nanostructure due to their excellent mechanical and physical attributes. CNTs were first discovered by S. Iijima in 1991 where he has reported in his article the synthesis of needle-like tubes by using an arc-discharge evaporation. After the immense discovery, the number of research on CNTs has increased significantly, focusing on their mechanical characteristics, dynamics properties and applications in nanotechnology. This paper attempts to present a review of a quite number of publications on CNTs and their dynamic properties. The main topics covered in this review are the applications of CNTs, their dynamic characteristics including the modeling and simulation of vibrating CNTs, and finally the vibration modes of CNTs.
Authors: In Pil Kang, Gyeong Rak Choi, Joo Yung Jung, Yong Hoon Chang, Yeon Sun Choi, Mark J. Schulz
Abstract: This paper experimentally investigates the power generation property of carbon nanotubes in an aqueous environment. Carbon nanotube based films are investigated in this paper as a new method for power generation based on ionic conductivity of the fluid. It is demonstrated that a carbon nanotube film that is bonded onto a structure vibrating with an electrolyte on the surface produces an alternating current without a net fluid flow. The power produced is smaller than for a piezoelectric material of the same size, but the CNT power generator is lightweight and has no moving parts, and does not require the structure to be immersed in an electrolyte. There are various possible applications for nanotube power generators.
Authors: In Pil Kang, Mark J. Schulz, Jong Won Lee, Gyeong Rak Choi, Joo Yung Jung, Jae Boong Choi, Sung Ho Hwang
Abstract: This study introduces a nano smart material to develop a novel sensor for Structural Health Monitoring (SHM) of mechanical and civil systems. Mechanical, civil, and environmental systems need to become self-sensing and intelligent to preserve their integrity, optimize their performance, and provide continuous safety for the users and operators. Present smart materials and structures have fundamental limitations in their sensitivity, size, cost, ruggedness, and weight. Smart materials developed using nanotechnology have the potential to improve the way we generate and measure motion in devices from the nano to the macro scale in size. Among several possible smart nanoscale materials, Carbon Nanotubes (CNT) have aroused great interest in the research community because of their remarkable mechanical, electrochemical, piezoresistive, and other physical properties. To address the need for new intelligent sensing based on CNT, this study presents piezoresistivity and electrochemical properties and preliminary experiments that can be applied for SHM. This study is anticipated to develop a new multifunctional sensor which can simultaneously monitor strain, stress and corrosion on a structure with a simple electric circuit.
Authors: Tong Qiu
Abstract: A comparable study on the effects of pristine and functionalized single-walled carbon nanotubes on schwann cells were conducted. Schwann cells were co-cultured with three types of SWNTs, purified raw SWNTs (C), hydroxyl purified SWNTs (C-OH) and carboxyl purified SWNTs (C-COOH) at 25μg/mL. C-COOH promoted the cell viability after 72h exposure and sustained its redox states by enhancing GPx expression. On the contrary, C and C-OH weaken the antioxidant activity due to the inhibition in main antioxidant enzymes and further led to the decline in cell viability. Carboxyl modification of the SWNTs helps to improve the biocompatibility of the SWNTs by strengthening the antioxidant ability.
Authors: Yan Fang Chen, Yun Soo Lim
Abstract: Carbon nanotubes (CNTs) in a high yield were synthesized by the decomposition of the methane gas with CCVD, in which two different reaction routes of sol-gel method prepared Fe-Mo- Mg-O catalyst. The two different routs influenced the wall number and defects of CNTs and the formation of CNTs. The concentration of Mo in the catalyst played a very important role in the yield of CNTs.
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