Academic literature on the topic 'Synthesis of carbon nanotubes (CNTs)'
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Journal articles on the topic "Synthesis of carbon nanotubes (CNTs)"
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Sun, Xiao Gang, Zhi Wen Qiu, Long Chen, et al. "Industrial Synthesis of Whisker Carbon Nanotubes." Materials Science Forum 852 (April 2016): 514–19. http://dx.doi.org/10.4028/www.scientific.net/msf.852.514.
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Since the first observation of carbon nanotubes (CNTs) in 1991, their synthesis techniques has been extensively investigated. The chemical vapor deposition (CVD) process have attracted much attention because of both their versatility and easy large scale production for CNTs . This paper is focused on a catalytic CVD-based method for synthesis of whisker multiwalled carbon nanotubes (WMWCNTs). The new type of carbon nanotube is similar to the whisker. The morphology of the WMWCNTs are very different from traditional carbon nanotubes prepared by traditional chemical vapor deposition process. The traditional CNTs were twisted and entangled with each other. These suggested that there are a lot of deficiencies on the CNTs and are difficult to disperse in matrix materials. The as-produced WMWCNTs are very straight and not entangled with each other. The line structure means that WMWCNTs are easily dispersed in matrix materials than traditional CNTs which are twined together. The crystallinity of WMWCNTs increased to 96% which was much higher than traditional CNTs after graphitization treatment at 2800°C.
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Kang, Ning, Jin Hua, Lizhen Gao, Bin Zhang, and Jiewen Pang. "The Interplay between Whey Protein Fibrils with Carbon Nanotubes or Carbon Nano-Onions." Materials 14, no. 3 (2021): 608. http://dx.doi.org/10.3390/ma14030608.
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Whey protein isolate (WPI) fibrils were prepared using an acid hydrolysis induction process. Carbon nanotubes (CNTs) and carbon nano-onions (CNOs) were made via the catalytic chemical vapor deposition (CVD) of methane. WPI fibril–CNTs and WPI fibril–CNOs were prepared via hydrothermal synthesis at 80 °C. The composites were characterized by SEM, TEM, FTIR, XRD, Raman, and TG analyses. The interplay between WPI fibrils and CNTs and CNOs were studied. The WPI fibrils with CNTs and CNOs formed uniform gels and films. CNTs and CNOs were highly dispersed in the gels. Hydrogels of WPI fibrils with CNTs (or CNOs) could be new materials with applications in medicine or other fields. The CNTs and CNOs shortened the WPI fibrils, which might have important research value for curing fibrosis diseases such as Parkinson’s and Alzheimer’s diseases. The FTIR revealed that CNTs and CNOs both had interactions with WPI fibrils. The XRD analysis suggested that most of the CNTs were wrapped in WPI fibrils, while CNOs were partially wrapped. This helped to increase the biocompatibility and reduce the cytotoxicity of CNTs and CNOs. HR-TEM and Raman spectroscopy studies showed that the graphitization level of CNTs was higher than for CNOs. After hybridization with WPI fibrils, more defects were created in CNTs, but some original defects were dismissed in CNOs. The TG results indicated that a new phase of WPI fibril–CNTs or CNOs was formed.
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Kumar, Arun. "Natural Materials—Interesting Candidates for Carbon Nanomaterials." Physchem 1, no. 1 (2021): 4–25. http://dx.doi.org/10.3390/physchem1010002.
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This review sums up the techniques used for the synthesis of carbon nanotubes (CNTs), carbon nanofibers (CNFs), and carbon nanospheres (CNSs) by employing catalysts of natural origin. Establishing large-scale production and commercial applications of CNTs for a sustainable society is still of high apprehension. In this regard, one of the major factors is the starting materials such as precursors and catalyst sources. However, natural materials contain a minor quantity of metals or metal oxides and could be employed as a catalyst source for the synthesis of CNTs, providing the possibility to replace expensive catalyst sources. A large number of successful studies have been completed so far and confirm that these developed methods for carbon nanomaterials synthesis exhibiting high quality from common natural materials are not only possible but, most importantly, promising and scalable. This review also highlights purification methods and recent promising applications of as-synthesized CNTs.
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Thurakitseree, Theerapol, and Chupong Pakpum. "Low-Cost Sputtering Process for Carbon Nanotubes Synthesis." Applied Mechanics and Materials 891 (May 2019): 195–99. http://dx.doi.org/10.4028/www.scientific.net/amm.891.195.
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According to their wonderful properties, carbon nanotubes (CNTs) have been well known for decades. The synthesis process and catalyst deposition method have also drawn attention to control the nanotube structure and properties. Sputtering method is then one promising option to grow the nanotubes in mass production. This method is, however, still costly. Here, we have presented a simple low-cost custom-made DC magnetron sputtering for catalyst thin film deposition. Three different metal thin films (Fe, Ni, Cu) deposited on Si substrates have been employed to investigate nanotube production. Prior to deposition of the catalysts, Al was used as supporting layer. (Al/Fe, Al/Ni, Al/Cu). CNTs were grown by chemical vapor deposition process at 800°C. Ethanol was preliminary used as a carbon source. It was found that CNTs could be successfully grown from only Al/Ni catalysts in our system with the diameter of approximately 200 nm, where the rest of samples were not observed. In addition, vertical-aligned CNTs with the thickness of about 10 μm could be obtained when acetylene was replaced instead of ethanol with reducing partial pressure of the feedstock. A large D-band at 1338 cm-1 with broader G-band at 1582 cm-1 from Raman spectra give a rise to multi layers growth of sp2 carbon walls. Such dimension suggests that it is the characteristic of multi-walled carbon nanotubes.
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Sahu, Anamika, Aviral Jain, and Arvind Gulbake. "THE ROLE OF CARBON NANOTUBES IN NANOBIOMEDICINES." International Journal of Pharmacy and Pharmaceutical Sciences 9, no. 6 (2017): 235. http://dx.doi.org/10.22159/ijpps.2017v9i6.18522.
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CNTs is a fullerene molecule, described in 1991 by the Japanese Scientist ‘‘Sumio Iijima’’ as tube-shaped of graphitic carbon, can be obtained either single or multi-walled nanotube, having a diameter measuring on the nanometer scale, and generally known as buckytubes. Carbon nanotubes (CNTs) have established much recent interest as new entities for experimental disease diagnosis and treatment because of their unique electronic, mechanical, thermal, spectroscopic, metallic, semiconducting and superconducting electron transport properties. Carbon nanotubes can be acquired in numerous ways, the general techniques are Arc discharge, Laser ablation, and Chemical vapour deposition (CVD). Carbon nanotubes are discussed in this review in terms of characters, history, structures, properties, synthesis, purification, characterization methods, toxicity and applications. Purification of nanotubes includes many techniques: Acid treatment, oxidation, annealing, ultrasonication, cutting, magnetic purification, chromatography techniques. Further functionalization enhanced the water solubility of CNT's and completely transformed their biocompatibility profile. Carbon nanotubes, due to their large surface areas, unique surface properties, and needle-like shape, can deliver a lot of therapeutic agents, including DNA, siRNAs and proteins to the target disease sites. CNTs can be readily excreted through the renal route by means of degradation through myeloperoxidase (MOP) enzyme. As CNTs have attracted the fancy of many scientists worldwide, the work beyond our expectations and their simple mechanism with long lasting life makes it more reliable to use. The unique and unusual properties of these structures make them a unique material with a whole range of promising applications.
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Wiak, Sławomir, Anna Firych-Nowacka, Krzysztof Smółka, Łukasz Pietrzak, Zbigniew Kołaciński, and Łukasz Szymański. "Induction heating process of ferromagnetic filled carbon nanotubes based on 3-D model." Open Physics 15, no. 1 (2017): 1061–66. http://dx.doi.org/10.1515/phys-2017-0134.
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AbstractSince their discovery by Iijima in 1991 [1], carbon nanotubes have sparked unwavering interest among researchers all over the world. This is due to the unique properties of carbon nanotubes (CNTs). Carbon nanotubes have excellent mechanical and electrical properties with high chemical and thermal stability. In addition, carbon nanotubes have a very large surface area and are hollow inside. This gives a very broad spectrum of nanotube applications, such as in combination with polymers as polymer composites in the automotive, aerospace or textile industries. At present, many methods of nanotube synthesis are known [2, 3, 4, 5, 6]. It is also possible to use carbon nanotubes in biomedical applications [7, 8, 9, 10, 11, 12, 13, 14], including the destruction of cancer cells using iron-filled carbon nanotubes in the hyperthermia process. Computer modelling results of Fe-CNTs induction heating process are presented in the paper. As an object used for computer model creation, Fe-CNTs were synthesized by the authors using CCVD technique.
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Liu, Yuan Chao, Bao Min Sun, and Zhao Yong Ding. "Catalyst Assisted Synthesis of Carbon Nanotubes Using the V-Shaped Pyrolysis Flame Method." Advanced Materials Research 79-82 (August 2009): 2123–26. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.2123.
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Flames offer potential for synthesis of carbon nanotubes(CNTs) in large quantities at considerably lower costs than that of other methods currently available. Synthesis CNTs from V-shaped pyrolysis flame is a kind of novel technique. This study aims to examine conditions for CNTs formation in V-shaped pyrolysis flame. Synthesis inner the V-shaped body and providing heat outer is distinct characteristic in the method. A premixed carbon monoxide/hydrogen gas diluted by helium gas flow was introduced into V-shaped body bottom centre. Simultaneously, as catalyst precursor, pentacarbonyl iron was entrained after ultrasonic atomization into the central pipe by helium gas flow. The rich acetylene/air premixed gas, providing heat source, was introduced into V-shaped body outside surface. Scanning electron microscopy and transmission electron microscopy images of the carbon products were examined. Large quantities of CNTs with the less carbon impurities were formed in the process. Carbon nanotubes can grow well when the sampling time was 5 minutes.A nanotube formation ‘window’ is evident with formation limited to fuel equivalence ratios between 1.6 and 1.8. Furthermore, temperature range was from 850°C to 950°C.Nanoparticles associated with nanotube bundles were identified as primarily ferric oxide.
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Mudimela, Prasantha R., Larisa I. Nasibulina, Albert G. Nasibulin, et al. "Synthesis of Carbon Nanotubes and Nanofibers on Silica and Cement Matrix Materials." Journal of Nanomaterials 2009 (2009): 1–4. http://dx.doi.org/10.1155/2009/526128.
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In order to create strong composite materials, a good dispersion of carbon nanotubes (CNTs) and nanofibers (CNFs) in a matrix material must be obtained. We proposed a simple method of growing the desirable carbon nanomaterial directly on the surface of matrix particles. CNTs and CNFs were synthesised on the surface of model object, silica fume particles impregnated by iron salt, and directly on pristine cement particles, naturally containing iron oxide. Acetylene was successfully utilised as a carbon source in the temperature range from 550 to750∘C. 5–10 walled CNTs with diameters of 10–15 nm at600∘Cand 12–20 nm at 750∘Cwere synthesised on silica particles. In case of cement particles, mainly CNFs with a diameter of around 30 nm were grown. It was shown that high temperatures caused chemical and physical transformation of cement particles.
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Itami, Kenichiro. "Toward controlled synthesis of carbon nanotubes and graphenes." Pure and Applied Chemistry 84, no. 4 (2012): 907–16. http://dx.doi.org/10.1351/pac-con-11-11-15.
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A bottom-up synthesis of structurally uniform carbon nanotubes (CNTs) and graphenes is recognized as one of the greatest challenges of primary importance in nanocarbon science. This paper highlights our efforts to address these challenges since 2005. These endeavors have led to (i) modular, size-selective, and scalable synthesis of [n]cycloparapheneylenes (CPPs), the shortest segment of armchair CNTs, (ii) design and synthesis of the shortest segment of chiral CNTs, and (iii) efficient synthesis of carbon nanosheets through catalytic C–H bond arylation of polycyclic aromatic hydrocarbons (PAHs). We consider these works as a possible first step toward a controlled synthesis of structurally uniform CNTs and nanographenes.
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Tan, Win Hon, Siew Ling Lee, and Cheng Tung Chong. "TEM and XRD Analysis of Carbon Nanotubes Synthesised from Flame." Key Engineering Materials 723 (December 2016): 470–75. http://dx.doi.org/10.4028/www.scientific.net/kem.723.470.
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A premixed flame burner system was utilised to synthesise carbon nanotubes (CNTs). The morphologies of highly-graphitic carbon nanotubes were characterised by using transmission electron microscopy (TEM) and X-ray powder diffraction (XRD). The XRD analysis shows the spectrum of a typical CNT, while TEM imaging shows the physical structure of the carbon nanotubes. CNTs were grown effectively on a Ni-contained substrate in an elevated temperature environment. The flame synthesised CNTs were of high crystalline, multi-wall structure, and contained relatively less impurities and amorphous carbon. The CNT intershell spacing values quantified using TEM and XRD are 0.317 nm and 0.344 nm respectively. CNTs produced from flame synthesis are based on the tip-growth model and vapor-liquid-solid (VLS) mechanism.
Dissertations / Theses on the topic "Synthesis of carbon nanotubes (CNTs)"
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Bera, Debasis. "ARC-DISCHARGE IN SOLUTION: A NOVEL SYNTHESIS METHOD FOR CARBON NANOTUBES AND IN SITU DECORATION OF CARBON NANOTUBES WITH NANOPAR." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2609.
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Nanotechnology has reached the status of the 21st century's leading science and technology based on fundamental and applied research during the last two decades. An important feature of nanotechnology is to bridge the crucial dimensional gap between the atomic and molecular fundamental sciences and microstructural scale of engineering. Accordingly, it is very important to have an in-depth understanding of the synthesis of nanomaterials for the use of state-of-the-art high technological devices with enhanced properties. Recently, the 'bottom-up' approach for the fabrication of nanomaterials has received a great deal of attention for its simplicity and cost effectiveness. Tailoring the various parameters during synthesis of selected nanoparticles can be used to fabricate technologically important components. During the last decade, carbon nanotubes (CNTs) have been envisioned for a host of different new applications. Although carbon nanotubes can be synthesized using a variety of techniques, large-scale synthesis is still a great challenge to the researchers. Three methods are commonly used for commercial and bulk productions of carbon nanotubes: arc-discharge, chemical vapor deposition and laser ablation. However, low-cost, large-scale production of high-quality carbon nanotubes is yet to be reported. One of the objectives of the present research is to develop a simplified synthesis method for the production of large-scale, low-cost carbon nanotubes with functionality. Herein, a unique, simple, inexpensive and one-step synthesis route of CNTs and CNTs decorated with nanoparticles is reported. The method is simple arc-discharge in solution (ADS). For this new method, a full-fledged optoelectronically controlled instrumen is reported here to achieve high efficiency and continuous bulk production of CNTs. In this system, a constant gap between the two electrodes is maintained using a photosensor which allows a continuous synthesis of the carbon nanostructures. The system operates in a feedback loop consisting of an electrode-gap detector and an analogue electronic unit, as controller. This computerized feed system was also used in single process step to produce in situ-decorated CNTs with a variety of industrially important nanoparticles. To name a few, we have successfully synthesized CNTs decorated with 3-4 nm ceria, silica and palladium nanoparticles for many industrially relevant applications. This process can be extended to synthesize decorated CNTs with other oxide and metallic nanoparticles. Sixty experimental runs were carried out for parametric analysis varying process parameters including voltage, current and precursors. The amount of yield with time, rate of erosion of the anode, and rate of deposition of carbonaceous materials on the cathode electrode were investigated. Normalized kinetic parameters were evaluated for different amperes from the sets of runs. The production rate of pristine CNT at 75 A is as high as 5.89 ± 0.28 g.min-1. In this study, major emphasis was given on the characterizations of CNTs with and without nanoparticles using various techniques for surface and bulk analysis of the nanostructures. The nanostructures were characterized using transmission electron microscopy, high resolution transmission electron microscopy, scanning transmission electron microscopy, energy dispersive spectroscopy and scanning electron microscopy, x-ray photo electron spectroscopy, x-ray diffraction studies, and surface area analysis. Electron microscopy investigations show that the CNTs, collected from the water and solutions, are highly pure except the presence of some amorphous carbon. Thermogravimetric analysis and chemical oxidation data of CNTs show the good agreement with electron microscopy analysis. The surface area analysis depicts very high surface area. For pristine multi-walled carbon nanotubes, the BET surface area is approximately 80 m2.g-1. X-ray diffraction studies on carbon nanotubes shows that the products are clean. Nano-sized palladium decorated carbon nanotubes are supposed to be very efficient for hydrogen storage. The synthesis for in-situ decoration of palladium nanoparticles on carbon nanotubes using the arc discharge in solution process has been extensively carried out for possible hydrogen storage applications and electronic device fabrication. Palladium nanoparticles were found to form during the reduction of palladium tetra-chloro-square planar complex. The formation of such a complex was investigated using ultraviolet-visible spectroscopic method. Pd-nanoparticles were simultaneously decorated on carbon nanotubes during the rolling of graphene sheets in the arc-discharge process. Zero-loss energy filtered transmission electron microscopy and scanning transmission electron microscopy confirm the presence of 3 nm palladium nanoparticles. The deconvoluted X-ray photoelectron spectroscopy envelope shows the presence of palladium. Surface area measurements using BET method show a surface area of 28 m2.g-1. The discrepancy with pristine CNTs can be explained considering the density of palladium (12023 kg.m-3). Energy dispersive spectroscopy suggests no functionalization of chlorine to the sidewall of carbon nanotubes. The presence of dislodged graphene sheets with wavy morphology as observed with high-resolution transmission electron microscopy supports the formation of CNTs through the 'scroll mechanism'.<br>Ph.D.<br>Department of Mechanical, Materials and Aerospace Engineering;<br>Engineering and Computer Science<br>Materials Science and Engineering
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Zhang, Qiuhong. "Carbon Nanotubes on Carbon Fibers: Synthesis, Structures and Properties." Dayton, Ohio : University of Dayton, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1272515887.
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Thesis (Ph.D. in Materials Engineering) -- University of Dayton.<br>Title from PDF t.p. (viewed 06/23/10). Advisor: Liming Dai. Includes bibliographical references (p. 136-162). Available online via the OhioLINK ETD Center.
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Wasel, Wahed Rezk. "HEAT TRANSFER AND CHEMICAL PROCESSES IN CHEMICAL VAPOR DEPOSITION REACTOR FOR SYNTHESIS OF CARBON NANOTUBES." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_diss/386.
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A small-scale model of a CVD reactor was built. Axial and radial of major species concentrations and temperature profiles were obtained with a micro gas chromatograph and a fine thermocouple. Those temperature and species concentrations revealed detailed thermal and chemical structures of the CVD reactor.
The concentrations of argon plus hydrogen, methane, and C2Hx (C2H2 + C2H4 + C2H6) resulting from xylene decomposition were measured along the CVD at different temperatures. Ferrocene was added to xylene to investigate the effect of a catalyst on composition profiles. The results with ferrocene indicated an increase in CH4 and C2Hx concentrations. At 1000 C and above, the increase of C2Hx concentration is higher than that for CH4. The effect of ferrocene was very minor on the concentration of the gases. Finally composition and temperature profiles were measured and plotted for the radial direction at X=75 cm and T=1200 C.
The overall rate constant for the gas-phase reaction was calculated based on the measured species concentration data using the Benson and Shaw reaction mechanism. Our study showed that the Benson and Shaw mechanism could be used in the temperature range lower than 800 C.
Also the effect of hydrogen in the syntheses of CNTs, in the CVD reactor using xylene and ferrocene, was studied. Both single-step and two-step methods were applied. In the single-step method, the ferrocene was dissolved in the xylene. In the two step-method the catalyst preparation step was performed first; ferrocene powder was placed in the preheater for a certain period of time and carried by a mixture of argon and hydrogen at fixed concentration to get catalyst nanoparticles deposited on the reactor wall. Xylene then was injected to the reactor. To study the effect of hydrogen, the synthesized materials were observed by SEM and TEM. The results showed that the presence of hydrogen is essential for CNTs to be synthesized by the CVD method, and also the concentration of hydrogen in the reactor has a great effect on the quality of CNTs. The yield of CNTs in the two-step method was slightly higher than that in the one-step method.
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Almkhelfe, Haider H. "Scalable carbon nanotube growth and design of efficient catalysts for Fischer-Tropsch synthesis." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38213.
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Doctor of Philosophy<br>Department of Chemical Engineering<br>Placidus B. Amama<br>The continued depletion of fossil fuels and concomitant increase in greenhouse gases have encouraged worldwide research on alternative processes to produce clean fuel. Fischer-Tropsch synthesis (FTS) is a heterogeneous catalytic reaction that converts syngas (CO and H₂) to liquid hydrocarbons. FTS is a well-established route for producing clean liquid fuels. However, the broad product distribution and limited catalytic activity are restricting the development of FTS. The strong interactions between the active metal catalyst (Fe or Co) and support (Al₂O₃, SiO₂ and TiO₂) during post-synthesis treatments of the catalyst (such as calcination at ~500°C and reduction ~550°C) lead to formation of inactive and unreducible inert material like Fe₂SiO₄, CoAl₂O₄, Co₂SiO₄. The activity of FTS catalyst is negatively impacted by the presence of these inactive compounds. In our study, we demonstrate the use of a modified photo-Fenton process for the preparation of carbon nanotube (CNT)-supported Co and Fe catalysts that are characterized by small and well-dispersed catalyst particles on CNTs that require no further treatments. The process is facile, highly scalable, and involves the use of green catalyst precursors and an oxidant. The reaction kinetic results show high CO conversion (85%), selectivity for liquid hydrocarbons and stability.
Further, a gaseous product mixture from FTS (C1-C4) was utilized as an efficient feedstock for the growth of high-quality, well-aligned single-wall carbon nanotube (SWCNT) carpets of millimeter-scale heights on Fe and (sub) millimeter-scale heights on Co catalysts via chemical vapor deposition (CVD). Although SWCNT carpets were grown over a wide temperature range (between 650 and 850°C), growth conducted at optimal temperatures for Co (850°C) and Fe (750°C) yielded predominantly SWCNTs that are straight, clean, and with sidewalls that are largely free of amorphous carbon. Also, low-temperature CVD growth of CNT carpets from Fe and Fe–Cu catalysts using a gaseous product mixture from FTS as a superior carbon feedstock is demonstrated. The efficiency of the growth process is evidenced by the highly dense, vertically aligned CNT structures from both Fe and Fe–Cu catalysts even at temperatures as low as 400°C–a record low growth temperature for CNT carpets obtained via conventional thermal CVD. The use of FTS-GP facilitates low-temperature growth of CNT carpets on traditional (alumina film) and nontraditional substrates (aluminum foil) and has the potential of enhancing CNT quality, catalyst lifetime, and scalability.
We demonstrate growth of SWCNT carpets with diameter distributions that are smaller than SWCNTs in conventional carpets using a CVD process that utilizes the product gaseous mixture from Fischer-Tropsch synthesis (FTS-GP). The high-resolution transmission electron microscopic (HR-TEM) and Raman spectroscopic results reveal that the use of a high melting point metal as a catalyst promoter in combination with either Co (1.5 nm ± 0.7) at 850ºC or Fe (1.9 nm ± 0.8) at 750ºC yields smaller-diameter SWCNT arrays with narrow diameter distributions.
Scalable synthesis of carbon nanotubes (CNTs), carbon nanofibers (CNFs), and onion like carbon (OLC) in a batch reactor using supercritical fluids as a reaction media is demonstrated. The process utilizes toluene, ethanol, or butanol as a carbon precursor in combination with ferrocene that serves as a catalyst precursor and a secondary carbon source. The use of supercritical fluids for growth does not only provide a route for selective growth of a variety of carbon nanomaterials, but also provides a unique one-step approach that is free of aggressive acid treatment for synthesis of CNT-supported metallic nanoparticle composites for catalysis and energy storage applications.
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Turano, Stephan Parker. "Carbon Nanotubes chemical vapor deposition synthesis and application in electrochemical double layer supercapacitors /." Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-02242005-094827/unrestricted/turano%5Fstephan%5Fp%5F200505%5Fmast.pdf.
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Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2005.<br>Ready, Jud, Committee Co-Chair ; Carter, Brent, Committee Co-Chair ; Snyder, Bob, Committee Member ; Wang, Zhong Lin, Committee Member. Includes bibliographical references.
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Paul, Aniruddha. "Synthesis of Graphene - Carbon Nanotube Hybrid Structures." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-290574.
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Graphene and Carbon nanotubes (CNTs) have been researched for more than a decade due to their extraordinary properties and advantages towards applications like electronics, structural re-enforcements, thermal management and energy storage. Graphene-CNT hybrid structures have been predicted to further enhance the exceptional properties and overcome some of the shortcomings of the individual materials. Advantages of a structure consisting of vertically aligned carbon nanotubes (VACNTs) covalently bonded with graphene layers have been predicted to be especially favourable for applications like TIM, supercapacitors and battery electrodes. This project investigates two growth mechanisms for obtaining Graphene-VACNT structures using scalable processes. Shortcomings of previously done research on similar structures like graphene transfer and bad CNT alignment is solved. A novel growth mechanism is also investigated to set the foundation for research into a new approach to grow Graphene-CNT hybrid structures in the future. Chemical Vapor Deposition (CVD) was the method used to grow the graphene and CNT structures. The characterization was done using optical microscopy, Scanning electron microscopy (SEM) and Raman spectroscopy.<br>Grafen- och kolnanorör (CNT) har forskats i mer än ett decennium på grund av deras extraordinära egenskaper och fördelar gentemot applikationer som elektronik, strukturförstärkning, termisk hantering och energilagring. Grafen-CNT hybridstrukturer har förutspåtts ytterligare förbättra de exceptionella egenskaperna och övervinna några av bristerna i de enskilda materialen. Fördelar med en struktur som består av vertikalt inriktade kolnanorör (VACNT) som är kovalent bundna med grafenskikt har förutspåtts vara särskilt fördelaktiga för applikationer som TIM, superkondensatorer och batterielektroder. Detta projekt undersöker två tillväxtmekanismer för att erhålla Graphene-VACNT-strukturer med hjälp av skalbara processer. Brister i tidigare utförd forskning om liknande strukturer som grafenöverföring och dålig CNT-anpassning är lösta. En ny tillväxtmekanism undersöks också för att lägga grunden för forskning om ett nytt tillvägagångssätt för att växa Graphene- CNT hybridstrukturer i framtiden. Chemical Vapor Deposition (CVD) var metoden som användes för att odla grafen- och CNT-strukturerna. Karakteriseringen gjordes med optisk mikroskopi, Scanning electron microscopy (SEM) och Raman-spektroskopi.
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De, Jager Nicolaas Jacobus. "The investigation and development of gas sensors with carbon nanomaterials." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/17872.
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Thesis (MScEng)--Stellenbosch University, 2011.<br>ENGLISH ABSTRACT: In this research the possible utilization of carbon nanomaterials in gas sensing
applications are investigated. These materials include the 2-dimensional
honeycomb-lattice carbon structure called graphene, and the 1-dimensional structures
referred to as carbon nanotubes (CNTs). The extraordinary properties and
unique morphology of these nanomaterials, make them excellent candidates for
sensory applications. This research thus entails the investigation and development
of gas sensors with these carbon nanomaterials. This includes the synthesis
of CNTs via a chemical vapour deposition (CVD) technique and the fabrication
of resistive thin film sensors with the various materials. The functionalization
of carbon nanomaterials is also explored, which delivers promising results for
sensing gases at room temperature, especially acetylene (C2H2). Furthermore, a
unique method is developed to fabricate ultra thin aluminium microstructures.
These metallic electrodes are found to be ideal for nanomaterial integration. An
experiment is performed to manufacture an integrated sensor with MWCNTs
and following the results, a refinement of the procedure and the investigation of
FET-based devices are recommended. The results obtained during this work,
indicate that engineered carbon nanostructures, such as CNTs and graphene, can
potentially be applied in future sensing technologies.<br>AFRIKAANSE OPSOMMING: Hierdie navorsing ondersoek die moontlike toepassing van koolstof nano-materiale
as gas-sensor tegnologie. Hierdie materiale sluit die 2-dimensionele koolstof struktuur,
grafeen, asook die sogenaamde 1-dimensionele koolstof nano-buise in. Die
buitengewone eienskappe en unieke morfologie van hierdie nano-materiale, maak
hul uitstekende kandidate vir sensor toepassings. Hierdie navorsing ondersoek
dus die ontwikkeling van gas-sensors met koolstof nano-materiale, insluitend
die sintese van koolstof nano-buise deur middel van ’n chemiese damp-neerslag
proses, asook die fabrikasie van resistiewe dun film sensors. Die funksionalisering
van koolstof nano-materiale is ook ondersoek en belowende resultate is
opgelewer met betrekking tot die deteksie van gasse by kamertemperatuur, veral
vir asetileen (C2H2) gas. Verder is ’n unieke metode ontwikkel om ultra dun aluminium
mikrostrukture te vervaardig en hierdie metaal elektrodes word as ideaal
beskou vir die integrasie van nano-materiale. ’n Eksperiment is uitgevoer om
’n geïntegreerde sensor te vervaardig met multi-wand koolstof nano-buise, waarvan
die resultate aandui dat die proses verfyn moet word en dat die moontlike
toepassing van veld-effek-transistor toestelle ondersoek moet word. Die resultate
wat opgelewer is gedurende hierdie navorsing dui daarop dat ontwikkelde nanostrukture,
soos koolstof nano-buise en grafeen, as toekomstige sensor tegnologie
geïmplementeer kan word.
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Halonen, N. (Niina). "Synthesis and applications of macroscopic well-aligned multi-walled carbon nanotube films." Doctoral thesis, Oulun yliopisto, 2013. http://urn.fi/urn:isbn:9789526202105.
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Abstract The main objectives of this thesis are to synthesize macroscopic well-aligned multi-walled carbon nanotube films and, based on their electrical conductivity, porosity and structural uniformity, highlight potential applications for further development. In this thesis, catalytic chemical vapour deposition from ferrocene-xylene precursors is optimized to grow high quality films of long, aligned multi-walled carbon nanotubes on lithographically patterned templates in high (~800ºC) temperatures. The impacts of reaction time, temperature and precursor concentration on MWCNT film quality (film thickness, purity, density and nanotube diameter distribution) are studied. Because of the excellent control of growth selectivity and film thickness inherent to the method, several interesting applications, including solar cell and capacitor electrodes, contact brushes, coolers, particulate filters and catalyst membranes, have been developed for nanotube films in collaboration between Finnish and international research groups over the past few years. In this thesis, advanced capacitor electrodes with improved charge storage and efficient particulate filters are discussed in closer detail. As the high temperatures used for growing high quality carbon nanotubes often cause complications in cases where nanotubes need to be directly integrated with other materials, experiments were also conducted with the aim of making the growth temperature as low as possible. After testing several catalyst and precursor combinations, cobalt nanoparticles deposited on silica surfaces were found to form carbon nanotubes from vaporized cyclopentene oxide precursor already at 470°C. The results show that catalytic chemical vapour deposition is a feasible and versatile method that can be combined with photolithography to produce multi-walled carbon nanotube films with desired footprint area and thickness on various substrates. The demonstrated new applications and technical solutions are expected to contribute to further development leading to competitive practical devices based on carbon nanotubes<br>Tiivistelmä Tämän väitöstyön päätavoitteina ovat makroskooppisten, yhdensuuntaisista moniseinämäisistä hiilinanoputkista koostuvien kalvojen valmistaminen ja sovellutusten esittäminen perustuen kalvojen sähkönjohtavuuteen, huokoisuuten ja rakenteelliseen yhdenmukaisuuteen. Katalyyttis-kemiallinen höyryfaasikasvatusmenetelmä on optimoitu korkealaatuisten, yhdensuuntaisista, pitkistä moniseinämäisistä hiilinanoputkista koostuvien kalvojen tuottamiseen korkeissa lämpötiloissa (~800ºC) fotolitografialla kuvioiduille kasvualustoille käyttäen ferroseeni/ksyleeni-lähtöainetta. Reaktioajan, lämpötilan ja lähtöainepitoisuuden vaikutusta nanoputkikalvon laatuun on tutkittu tarkastelemalla kalvon paksuutta, puhtautta, tiheyttä ja nanoputkien läpimittajakaumaa. Erinomaisen kasvuselektiivisyyden ja kalvon paksuuden kontrolloimisen ansiosta nanoputkikalvoja voidaan räätälöidä useisiin mielenkiintoisiin sovellutuksiin (esim. aurinkokennot ja kondensaattorin elektrodit, hiiliharjat, jäähdyttimet, partikkelisuodattimet ja katalyyttikalvot), joita olemme kehittäneet viime vuosina yhdessä suomalaisten ja kansainvälisten tutkimusryhmien kanssa. Tässä väitöstyössä on tarkasteltu lähemmin uudentyyppisiä kondensaattorielektrodeja, joilla on parantunut sähkövarauksen varastointikyky, sekä tehokkaita partikkelisuodattimia. Hiilinanoputkien kasvattaminen korkeissa lämpötiloissa aiheuttaa usein ongelmia integroitaessa nanoputkia toisiin materiaaleihin. Tästä johtuen tutkimuksessa pyrittiin saamaan nanoputkien kasvatuslämpötila mahdollisimman alhaiseksi testaamalla useita lähtöaine-katalyytti-kombinaatioita, joista koboltti-nanopartikkelit piidioksidin päällä ja syklopenteenioksidi lähtöaineena muodostivat hiilinanoputkia jo 470°C:ssa. Tulosten perusteella katalyyttis-kemiallinen höyryfaasikasvatusmenetelmä yhdistettynä fotolitografiaan on hyvin monipuolinen tapa tuottaa moniseinämäisiä hiilinanoputkia halutulla kuviolla ja kalvonpaksuudella erilaisille substraateille. Tässä väitöstyössä demonstroitujen uusien sovellutusten ja teknisten ratkaisujen odotetaan johtavan uusiin, hiilinanoputkiin perustuviin kilpailukykyisiin käytännön laitteisiin
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Jayasinghe, Chaminda. "Synthesis and Characterization of Carbon Nanotube, Threads, Yarns, and Sheets." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1312292744.
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Pitkänen, O. (Olli). "On-device synthesis of customized carbon nanotube structures." Doctoral thesis, Oulun yliopisto, 2019. http://urn.fi/urn:isbn:9789526223179.
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Abstract Carbon nanotubes (CNTs) are known for their excellent mechanical, electrical and thermal properties, that have fostered a vast number of applications during the last two decades, from composites, electrodes and nanoelectonics components, to sensors and biological scaffolds. Direct integration of CNTs into devices is not straightforward, as high growth temperatures (above 600 °C) challenge the chemical and thermal stability of substrates, catalysts and other nearby materials or components. However, by decreasing growth temperature and/or working out protocols that take into account the thermal stability of the materials involved, it is possible to create several new types of architectures and devices with functionalities not shown before. In this work, we show that, with selection of the appropriate substrate, diffusion barrier and catalyst materials, direct growth of functional CNT films and their micropatterns may be achieved, not only on Si chips, but also on other atypical surfaces, using chemical vapor deposition. This thesis explores low-temperature CNT synthesis over bi- and trimetallic catalysts, and investigates the effect of diffusion barrier layers on the electrical properties of substrate-to-CNT contacts. On one hand, the lowest achieved CNT synthesis temperature (400 °C) is compatible with most silicon technologies, thus enabling direct integration of CNTs with materials and devices with low thermal budgets. On the other hand, the results of diffusion barrier studies helped us in designing and demonstrating on-chip micropatterned CNT structures for super and pseudocapacitor electrodes. In addition, we also show a method for maskless growth of CNT micropatterns using laser-treated steel and superalloy surfaces, whose surface diffusion properties change as a result of barrier-type metal oxide formation. Furthermore, we present CNT growth on carbon materials and demonstrate entirely carbon-based hierarchical composites for electromagnetic interference shielding applications, exhibiting outstanding absorption-based shielding performance. The results presented in this thesis are expected to contribute to a further expansion of CNT-based technologies, in particular with potential for future advances in high-frequency devices (arrays, amplifiers and shielding materials), energy materials (electrodes and scaffolds), as well as in nanoelectromechanical systems (sensors and actuators)<br>Tiivistelmä Hiilinanoputket tunnetaan niiden erinomaisista mekaanisista, sähköisistä ja termisistä ominaisuuksista, joita on hyödynnetty lukuisissa sovelluksissa viimeisen kahden vuosikymmenen aikana alkaen komposiiteista, elektrodeista, nanoelektroniikkakomponenteista ja sensoreista aina biologisiin tukirakenteisiin. Nanoputkien synteesi suoraan laitteessa ei ole suoraviivaista, sillä korkeat, yli 600 °C synteesilämpötilat asettavat haasteita substraatin, katalyytin sekä muiden lähellä olevien materiaalien ja komponenttien kemialliselle ja termiselle vakaudelle. Alentamalla synteesilämpötilaa ja/tai kehittämällä termisen vakauden huomioivia menetelmiä on mahdollista luoda uudenlaisia arkkitehtuureja ja sovelluksia ennennäkemättömillä ominaisuuksilla. Tässä työssä osoitetaan, että sopivan substraatin, diffuusiosuojan ja katalyyttimateriaalin valitsemalla funktionaalisten hiilinanoputkien synteesi on mahdollista piin lisäksi myös muille, epätavallisille pinnoille käyttäen kemiallista kaasufaasipinnoitusta. Väitöstyössä käsitellään hiilinanoputkien matalan lämpötilan synteesiä hyödyntäen kaksi- ja kolmimetallisia katalyyttejä sekä tutkitaan diffuusiosuojakerroksen sähköistä vaikutusta substraatin ja hiilinanoputkien väliseen kontaktiin. Alin saavutettu synteesilämpötila (400 °C) on yhteensopiva useimpien piiteknologioiden kanssa, mikä mahdollistaa nanoputkien suoran integroinnin matalaa lämpötilaa edellyttäville materiaaleille. Työssä tutkitun diffuusiosuojakerroksen kehitys mahdollisti myös piisirun päälle toteutettujen hiilinanoputkipohjaisten super- ja pseudokondensaattorielektrodien demonstroinnin. Lisäksi työssä esitetään menetelmä, jossa laserkäsittelemällä teräs- ja supermetalliseospinta, jonka avulla mikrokuvioitu hiilinanoputkien kasvu ilman litografiaprosessia on mahdollista. Viimeisenä työssä esitetään hiilinanoputkien synteesi suoraan toiselle hiilimateriaalille ja demonstroidaan täysin hiilipohjainen, hierarkkinen komposiittimateriaali erinomaisella absorptioon perustuvalla suojauskyvyllä sähkömagneettisiin häiriösuojaussovelluksiin. Väitöstyössä esitettyjen tulosten odotetaan osaltaan edistävän hiilinanoputkipohjaisten teknologioiden kehitystä erityisesti korkean taajuuden laitteissa, energiamateriaaleissa sekä nanosähkömekaanisissa järjestelmissä
Books on the topic "Synthesis of carbon nanotubes (CNTs)"
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Yellampalli, Siva. Carbon nanotubes: Synthesis, characterization, applications. InTech, 2011.
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Monthioux, Marc. Carbon meta-nanotubes: Synthesis, properties, and applications. John Wiley & Sons, 2012.
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Harris, Peter J. F. Carbon nanotube science: Synthesis, properties and applications. Cambridge University Press, 2009.
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Nazario, Martin, ed. Carbon nanotubes and related structures: Synthesis, characterization, functionalization, and applications. Wiley-VCH, 2010.
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Fragments of fullerenes and carbon nanotubes: Designed synthesis, unusual reactions, and coordination chemistry. Wiley, 2011.
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Papadopoulos, Christo. Nanotube engineering and science: Synthesis and properties of highly ordered carbon nanotube arrays and Y-junction carbon nanotubes. National Library of Canada, 2000.
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Kyotani, T., and H. Orikasa. Templated carbon nanotubes and the use of their cavities for nanomaterial synthesis. Edited by A. V. Narlikar and Y. Y. Fu. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199533060.013.11.
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This article focuses on templated carbon nanotubes (CNTs) and how their cavities can be used for the synthesis of nanomaterials. In particular, it demonstrates how effectively the CNTs can be functionalized by the template carbonization technique. The article first describes the method for synthesizing CNTs and carbon nano-test-tubes (CNTTs). It then considers the controlled filling of magnetic materials into CNTTs, taking into account the electrochemical deposition of Ni-Fe alloy and the magnetic properties of NiFe-filled CNTTs. It also examines the synthesis of water-dispersible and magnetically responsive CNTTs, with emphasis on water dispersibility and the effect of magnetic interaction. Finally, it shows how the cavities of templated CNTs can be utilized as a reaction field for the hydrothermal synthesis of one-dimensional nanomaterials.
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Collins, Philip G. Defects and disorder in carbon nanotubes. Edited by A. V. Narlikar and Y. Y. Fu. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199533053.013.2.
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This article examines the physical consequences of defects and disorder in carbon nanotubes (CNTs). It begins with a pedagogical categorization of the types of defects and disorder found in CNTs, including lattice vacancies and bond rotations, and goes on to discuss considers two primary sources of disorder: the environment surrounding a CNT and the substrate supporting it. It then considers various experimental methods for locating defects in CNTs, including atomic-resolution scanning tunnelling microscopy, transmission electron microscopy, electrochemical and chemoselective labelling, optical spectroscopy, and electrical conductance. The article concludes with a review of the long-range consequences of defects and disorder on the physical properties of CNTs such as chemical reactivity, electrical transport, and mechanical effects.
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Yellampalli, Siva, ed. Carbon Nanotubes - Synthesis, Characterization, Applications. InTech, 2011. http://dx.doi.org/10.5772/978.
Full textBook chapters on the topic "Synthesis of carbon nanotubes (CNTs)"
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Peroulis, Dimitrios, Prashant R. Waghmare, Sushanta K. Mitra, et al. "Carbon Nanotubes (CNTs)." In Encyclopedia of Nanotechnology. Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-90-481-9751-4_100102.
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Chandrasekhar, Prasanna. "Introducing Carbon Nanotubes (CNTs)." In Conducting Polymers, Fundamentals and Applications. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-69378-1_1.
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Campidelli, Stéphane, Stanislaus S. Wong, and Maurizio Prato. "Functionalized Carbon Nanotubes: (X-CNTs)." In Carbon Meta-Nanotubes. John Wiley & Sons, Ltd, 2011. http://dx.doi.org/10.1002/9781119954743.ch3.
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Sloan, Jeremy, and Marc Monthioux. "Filled Carbon Nanotubes: (X@CNTs)." In Carbon Meta-Nanotubes. John Wiley & Sons, Ltd, 2011. http://dx.doi.org/10.1002/9781119954743.ch5a.
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Bacsa, Revathi R., and Philippe Serp. "Decorated (Coated) Carbon Nanotubes: (X/CNTs)." In Carbon Meta-Nanotubes. John Wiley & Sons, Ltd, 2011. http://dx.doi.org/10.1002/9781119954743.ch4.
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Golberg, Dmitri, and Mauricio Terrones. "Heterogeneous Nanotubes: (X*CNTs, X*BNNTs)." In Carbon Meta-Nanotubes. John Wiley & Sons, Ltd, 2011. http://dx.doi.org/10.1002/9781119954743.ch6.
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Hasnain, Md Saquib, and Amit Kumar Nayak. "CNTs in Solubility Enhancement." In Carbon Nanotubes for Targeted Drug Delivery. Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-15-0910-0_9.
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Kong, Ling Bing, Weili Yan, Yizhong Huang, Wenxiu Que, Tianshu Zhang, and Sean Li. "Carbon Nanomaterials Based on Carbon Nanotubes (CNTs)." In Advances in Nanomaterials. Springer India, 2016. http://dx.doi.org/10.1007/978-81-322-2668-0_2.
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Das, Rasel, and Sayonthoni Das Tuhi. "Carbon Nanotubes Synthesis." In Carbon Nanostructures. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-95603-9_3.
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Kharissova, Oxana Vasilievna, and Boris Ildusovich Kharisov. "Cost and Main Applications of Soluble CNTs." In Solubilization and Dispersion of Carbon Nanotubes. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-62950-6_6.
Full textConference papers on the topic "Synthesis of carbon nanotubes (CNTs)"
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Kennedy, Lawrence A. "Carbon Nanotubes, Synthesis, Growth and Orientation Control." In ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2006. http://dx.doi.org/10.1115/icnmm2006-96035.
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The combustion synthesis of carbon nanotubes is reviewed, examining their formation and control in diffusion flames. The production of CNTs in the absence of a catalyst, the range of morphology of nanostructures when a catalyst is employed, control of the growth and orientation of CNTs and their arrays through the use of electric fields and the functional coating of CNTs with polymers using supercritical CO2 are discussed. Application of these techniques to other materials is discussed.
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Mortuza, S. M., and Soumik Banerjee. "Controlled Self-Assembly of Functionalized Carbon Nanotubes on Silicon Substrates." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-66579.
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Self-assembly of carbon nanotubes (CNTs) on silicon substrates has myriad applications including nanotube based electrochemical energy conversion and storage devices, such as batteries and super-capacitors. Patterned assembly of CNTs is required in order to control the effective electrical conductivity and mechanical properties of these devices and achieve substantial improvement in their performance. Solution-based self-assembly of CNTs provides a cost-effective means to synthesize uniform vertically or horizontally aligned nanostructures on top of substrates. However, self-assembly of CNTs is a complex dynamical process that involves intermolecular interaction between the CNTs and that between the nanotubes and the substrate as well as solvent molecules. The transport properties of CNTs and solvents also play an important role. The scientific literature lacks detailed study of understanding the mechanism of self-assembly of CNTs on substrates during synthesis process. Often times, nanotubes are functionalized in an effort to make them more soluble and induce partial charges to control the self-assembly. Some of the key factors that govern the transportation and self-assembly of functionalized CNTs are surface charge density on substrate and electrostatic interaction of the functionalized CNTs with the substrate. In an effort to mimic the conditions during the synthesis of carbon nanomaterials on silicon substrate, we have employed molecular dynamics simulations to simulate both pure and functionalized CNTs sandwiched between silicon substrates in presence of commonly used solvent, water. Our simulations indicate that both pure and functionalized CNTs are not significantly soluble in water and form agglomerates. Our results also illustrate that neither pure nor functionalized CNTs tend to deposit on silicon substrates in water. Results presented in this study provide fundamental insight that can help to understand the agglomeration and orientation of CNTs in water.
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Thangapandian, N., S. Balasivanandha Prabu, and R. Paskaramoorthy. "Synthesis and Characterization of High Performance Polymer Nanocomposite Using Carbon Nanotubes as Fillers." In ASME 2013 International Manufacturing Science and Engineering Conference collocated with the 41st North American Manufacturing Research Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/msec2013-1251.
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In this work, the chemical vapour deposition (CVD) method is used for the production of carbon nanotubes (CNTs). The catalyst, Fe/MgO, was prepared through sonication technique. It was heated to 600 °C for 6 hours and this was used as the template for growing the CNTs using acetylene as carbon precursor. The deposited CNTs were separated by acid treatment followed by air oxidation. The purified CNTs were examined by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The CNTs were observed to have a multi-wall structure with the diameter in the range of 10–20 nm. These multiwalled carbon nanotubes (MWCNTs) were used as filler material in an epoxy matrix. Sonication technique was used to achieve uniform dispersion of CNTs within the matrix. The CNT/epoxy nanocomposite was cured at a temperature of 100 °C for 3 hours. Tensile strength, flexural strength, fire retardant properties and surface conductivity were studied. The results reveal that addition of MWCNTs to the epoxy promotes substantial improvement to the above mentioned properties.
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Huitink, David R., Debjyoti Banerjee, and Saion K. Sinha. "Precise Control of Carbon Nanotube Synthesis of a Single Chirality." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42588.
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This work demonstrates precise control over the synthesis conditions and location during CNT formation, such that single chirality tubes are obtainable. This technique obviates two significant hurdles that prevent the exploitation of CNTs in micro- and nano-devices. Microelectronic applications require precise location and chirality of synthesized CNTs. Conventional CVD synthesis techniques typically yield mixtures of CNTs (semi-conducting and metallic types) that grow at random locations. Dip Pen Nanolithography (DPN) techniques were used to deposit the catalysts at precisely defined locations and to pattern the catalysts on a substrate with specific sizes as well as to control the catalyst composition. After deposition of catalysts, a low temperature Chemical Vapor Deposition (CVD) process was used to synthesize CNT. Various known catalysts were deposited. Characterization studies before and after CVD synthesis of CNT showed that the CNT were of a single chirality as well as uniform diameter (with a very narrow range of variability). The results indicate that the chirality of the synthesized CNT can be controlled by changing the synthesis conditions (e.g., size of the catalyst patterns, composition of the catalysts, temperature of CVD, gas flow rates, etc.).
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Sabet, Seyed Morteza, Hassan Mahfuz, Andrew C. Terentis, and Javad Hashemi. "A New Approach to the Synthesis of Carbon Nanotube-Polyhedral Oligomeric Silsesquioxane (POSS) Nanohybrids." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-50925.
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To date, the functionalization of carbon nanotubes (CNTs) with Polyhedral Oligomeric Silsesquioxanes (POSS) has become one of the most intensively explored methods to produce CNT-based nanostructure composite materials. In this study, a simple and effective synthesizing method has been reported to prepare a nanohybrid material consisting of multi-walled carbon nanotubes (MWCNT) and aminopropylisobutyl-POSS. The approach is based on covalent bonding between CNTs and POSS molecules. Characterization of the as-received materials as well as the POSS-treated CNTs has been performed. Raman and Fourier transform infrared spectroscopic analyses verify the covalent grafting of POSS onto CNT walls through the formation of amide bonds. TEM studies reveal the attachment of relatively high amount of POSS to the CNT walls in POSS-treated product. TGA observations suggest that the presence of relatively high amount of POSS in MWCNT-POSS product is responsible for the thermal stability of CNTs at temperature range of RT–200 °C. The resulting nanohybrids with improved functionality and thermal stability would be good candidates as reinforcing materials for compatible polymer matrices.
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Tehrani, Mehran, Masoud Safdari, Scott W. Case, and Marwan S. Al-Haik. "Using Multiscale Carbon Fiber/Carbon Nanotubes Composites for Damping Applications." In ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2011. http://dx.doi.org/10.1115/smasis2011-5087.
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A novel technique to grow carbon nanotubes (CNTs) on the surface of carbon fibers in a controlled fashion using simple lab set up is developed. Growing CNTs on the surface of carbon fibers will eliminate the problem of dispersion of CNTs in polymeric matrices. The employed synthesis technique retains the attractive feature of uniform distribution of the grown CNTs, low temperature of CNTs’ formation, i.e. 550 °C, via cheap and safe synthesis setup and catalysts. A protective thermal shield of thin ceramic layer and subsequently nickel catalytic particles are deposited on the surface of the carbon fiber yarns using magnetron sputtering. A simple tube furnace setup utilizing nitrogen, hydrogen and ethylene (C2H4) were used to grow CNTs on the carbon fiber yarns. Scanning electron microscopy revealed a uniform areal growth over the carbon fibers where the catalytic particles had been sputtered. The structure of the grown multiwall carbon nanotubes was characterized with the aid of transmission electron microscopy (TEM). Dynamical mechanical analysis (DMA) was employed to measure the loss and storage moduli of the hybrid composite together with the reference raw carbon fiber composite and the composite for which only ceramic and nickel substrates had been deposited on. The DMA tests were conducted over a frequency range of 1–40 Hz. Although the storage modulus remained almost unchanged over the frequency range for all samples, the loss modulus showed a frequency dependent behavior. The hybrid composite obtained the highest loss modulus among other samples with an average increase of approximately 25% and 55% compared to composites of the raw and ceramic/nickel coated carbon fibers, respectively. This improvement occurred while the average storage modulus of the hybrid composite declined by almost 9% and 15% compared to the composites of reference and ceramic/nickel coated samples, respectively. The ultimate strength and elastic moduli of the samples were measured using standard ASTM tensile test. Results of this study show that while the addition of the ceramic layer protects the fibers from mechanical degradation it abolishes the mechanisms by which the composite dissipates energy. On the other hand, with almost no compromise in weight, the hybrid composites are good potential candidate for damping applications. Furthermore, the addition of CNTs could contribute to improving other mechanical, electrical and thermal properties of the hybrid composite.
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Tomoda, Masahiro, Teppei Kawahara, Yohei Tasaki, et al. "Carbon Nanotube Synthesis From Metal Nanoparticles Size-Classified by a Differential Mobility Analyzer." In ASME/JSME 2011 8th Thermal Engineering Joint Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajtec2011-44414.
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In this study, carbon nanotubes (CNTs) were synthesized from size-classified catalyst metal nanoparticles to observe the effect of the nanoparticles’ diameter on the diameter of the CNTs. The nanoparticles were generated by laser vaporization and classified by a differential mobility analyzer, which sorts them by diameter according to differences in electrical mobility. After classification, the nanoparticles were collected on a Si substrate. CNTs were synthesized from these catalyst metal nanoparticles by using chemical vapor deposition. This experiment synthesized mainly multi-walled carbon nanotubes (MWNTs), with a small amount of single-walled carbon nanotubes (SWNTs). The reason is thought to be that the particles’ diameters were appropriate for MWNT synthesis.
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Zimmermann, Kristen A., Jianfei Zhang, Harry Dorn, Christopher Rylander, and Marissa Nichole Rylander. "Synthesis and Cytotoxicity Analysis of Carbon Nanohorn-Quantum Dot Complexes." In ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53968.
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Carbon nanoparticles have the potential to significantly impact the medical field over the next decade. Currently, carbon nanoparticles are being studied for a myriad of applications, including drug delivery, selective laser therapy, imaging, and biosensing. The most common type of carbon particles being investigated are carbon nanotubes (CNTs). CNTs are attractive materials for medical applications because of their physical properties and the ease with which they can be surface modified; however, there is a great deal of controversy over their possible toxicity. A more novel type of CNT that was discovered in 1999 by Iijima et al. is the carbon nanohorn [1]. Individual single-walled nanohorns (SWNHs) are single graphene sheets that roll into a conical open ended structure. The open ends of these cones are then attracted to one another through van der Waals interactions and form a flower-like final structure [2]. SWNHs are more favorable for medical applications because they are produced without the use of metal catalysts abating the concern of toxicity associated with CNTs.
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Talwar, Brijpal Singh, Kambiz Chizari, Shuangzhuang Guo, and Daniel Therriault. "Investigation of Carbon Nanotubes Mixing Methods and Functionalizations for Electrically Conductive Polymer Composites." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-39970.
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The growing popularity of Poly lactic acid (PLA) is related to its biocompatibility, good mechanical properties, and its synthesis from renewable resources. PLA can be compounded with electrically conductive fillers (e.g., carbon nanotubes (CNTs)) to form carbon polymer composites (CPC). These fillers provide the conductive functionality by forming percolative paths. Featuring very low weight densities, CPCs have the potential to replace metals in the electronic industry if they exhibit similar electrical conductivities. The current challenges being faced during the mixing of CNTs in a polymer matrix are the formation of aggregates due to the strong van der Waals forces and the breakage of the CNTs during dispersion. In this study, we compare: (1) two fabrication methods to create CPCs (i.e., solution mixing by sonication and extrusion) and (2) effects of various CNT functionalization techniques (i.e., acid and plasma treatments) on the conductivity of the CPCs. First, the composites comprising of 30% PLA by weight in Dichloromethane (DCM) and CNTs in different concentrations (up to 5wt.%) are fabricated by two step sonication method (i.e., dissolving PLA in DCM and then dispersing the CNTs in the polymer solution). Second, CPCs are fabricated using a micro twin screw extruder operating at 180°C. To verify the effects of functionalization of the CNTs on the conductivity of composites, the CNTs are functionalized via three methods: - HNO3 acid functionalization, 3:1 ratio HNO3 + H2SO4 acid (stronger) functionalization and N2 plasma functionalization. CPC fibers are drawn using the solvent-cast printing method. These fibers are then tested for their electrical conductivity using the two probe method. The maximum electrical conductivity is showed by the 5% CNT concentration samples at 3.97 S/m and 25.16 S/m for the CPC fibers obtained via the solution blend and the extrusion methods, respectively. Regarding the functionalized CNTs, conductivity measurements show a negative effect of the CNTs functionalization on the electrical properties of the CPC.
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Aatre, K., J. Xie, L. F. Chen, J. K. Abraham, and V. K. Varadan. "Synthesis of vertically aligned carbon nanotubes, magnetic nanotubes, and magnetic CNTs for cellular growth and detection." In The 15th International Symposium on: Smart Structures and Materials & Nondestructive Evaluation and Health Monitoring, edited by Vijay K. Varadan. SPIE, 2008. http://dx.doi.org/10.1117/12.776255.
Full textReports on the topic "Synthesis of carbon nanotubes (CNTs)"
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Whitaker, Craig, Jay R. Heckert, and Ian C. Uber. Synthesis of Amide Functionalized Carbon Nanotubes. Defense Technical Information Center, 2007. http://dx.doi.org/10.21236/ada519137.
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Tse, Stephen D. Encapsulating Reactive Nanoparticles in Carbon Nanotubes Using Flame-Based Synthesis. Defense Technical Information Center, 2008. http://dx.doi.org/10.21236/ada500573.
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Jorge Camacho, Mahesh Subramanya, and Ahsan R. Choudhuri. Flame Synthesis of Carbon Nanotubes Using Low Calorific Value Gases. Office of Scientific and Technical Information (OSTI), 2007. http://dx.doi.org/10.2172/924881.
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Yap, Yoke Khin. Heterojunction of Boron Nitride and Carbon Nanotubes: Synthesis and Characterization. Office of Scientific and Technical Information (OSTI), 2017. http://dx.doi.org/10.2172/1406128.
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Lee, Kun-Hong. Low Temperature Synthesis of Carbon Nanotubes by Direct Microwave Irradiation. Defense Technical Information Center, 2007. http://dx.doi.org/10.21236/ada472795.
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