scholarly journals Free energy surface of initial cap formation in carbon nanotube growth

2021 ◽  
Author(s):  
Satoru Fukuhara ◽  
Yasushi Shibuta
Keyword(s):  
Carbon Nanotubes ◽  
Free Energy ◽  
Carbon Nanotube ◽  
Energy Surface ◽  
Catalyst Surface ◽  
Important Process ◽  
Free Energy Surface ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth ◽  
Carbon Network

Initial cap formation is an important process of carbon nanotubes (CNTs) growth where hexagonal carbon network is lifted off from the catalyst surface. In this study, free energy surface (FES)...

Reactor Scale Model of Multiwalled Carbon Nanotube Growth in a Tube Flow Chemical Vapor Deposition Reactor

2009 ◽  
Author(s):  
Jeffrey J. Lombardo ◽  
Wilson K. S. Chiu
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Multiwalled Carbon Nanotubes ◽  
Computational Models ◽  
Chemical Vapor ◽  
Scale Model ◽  
Tube Flow ◽  
Multiwalled Carbon ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth

Even though a large number of applications for multiwalled carbon nanotubes have been proposed, there is relatively limited knowledge about the optimal conditions in which to create multiwalled carbon nanotubes (MWNTs). Computational models have been shown to be a promising tool to determine the best carbon nanotube growth conditions. In this paper the growth of MWNTs in a tube flow CVD reactor was studied through the use of the commercial software package COMSOL, where details steps have been described to reformulate an existing single walled carbon nanotube (SWNT) growth model to accommodate MWNTs followed by validation and growth rate prediction. Higher growth rates were predicted for MWNTs than SWNTs which is a result of the increase in pathways for carbon to form carbon nanotubes based on the additional walls. Results indicate that selecting the correct number of walls can be important to the results of the model.

Carbon Nanotube Growth from Nanoscale Clusters Formed by Ion Implantation

2005 ◽  
Vol 908 ◽  
Author(s):  
Yongho Choi ◽  
Jennifer Sippel Oakley ◽  
Andrew Rinzler ◽  
Ant Ural
Keyword(s):  
Thin Films ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Ion Implantation ◽  
Silicon Dioxide ◽  
Small Diameter ◽  
Iron Ions ◽  
Nanoscale Clusters ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth

AbstractWe have demonstrated that iron ions implanted into silicon dioxide thin films form nanoscale clusters which can act as catalyst for carbon nanotube growth. We have implanted iron ions with an energy of 60 keV and three different doses (1014, 1015, and 1016 cm-2) into silicon dioxide thin films thermally grown on silicon substrates. We then used chemical vapor deposition (CVD) to grow carbon nanotubes on these ion implanted substrates with methane as the precursor gas. We studied the effect of ion implantation dose on the structural properties of the nanoscale clusters, as well as the carbon nanotubes nucleated from these clusters. The nanoscale clusters and grown nanotubes were characterized by Atomic Force Microscopy and Raman spectroscopy. The electrical characteristics of the as-grown nanotubes were also characterized. We found that growth of low density, horizontal, and small diameter carbon nanotubes on silicon dioxide is possible using this nucleation technique.

Carbon Nanotube Growth on Different Types of Tool Steel Substrates

2007 ◽  
Vol 1057 ◽  
Author(s):  
Gulfem Ipek Nasuf ◽  
Max Yen
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Tool Steel ◽  
Hydrogen Gas ◽  
Growth Surface ◽  
Gas Treatment ◽  
Different Types ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth ◽  
Steel Substrates

ABSTRACTThis paper investigates the effectiveness of different pretreatment methods applied on M50, M35, and W4 type of tool steel substrates for direct growth of carbon nanotubes. The pretreatments explored include treatment with sand paper polishing, nitric acid (HNO3) etching, and high temperature hydrogen gas treatment. Furthermore, in order to establish a correlation between the steel surface average roughness value and the carbon nanotube growth, surface topography of steel substrates created by mechanical polishing were measured before actual growth process. Grown carbon nanostructures were shown by SEM and TEM to be multi-walled carbon nanotubes (MWCNTs) and vapor grown carbon nanofibers (VGCFs). It was found that under the same pretreatment conditions, even when the same roughness values were achieved and the same thermal chemical vapor deposition conditions were applied, grown nanostructures on different types of tool steel substrates showed dissimilarity.

Functionalisation of Microfluidic Channels with In Situ Grown Carbon Nanotubes

2005 ◽  
Vol 872 ◽  
Author(s):  
K. Gjerde ◽  
T. Schurmann ◽  
K.B.K. Teo ◽  
M. Aono ◽  
W.I. Milne ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Surface Properties ◽  
Microfluidic Channels ◽  
Electrical Field ◽  
Multiwalled Carbon ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth ◽  
Local Distortions

AbstractWe present a new route towards customizing the surface properties of microfluidic channels, by a forest of in situ grown multiwalled carbon nanotubes (CNT). Local distortions of the electrical field direction are used to control the direction of the carbon nanotube growth.

Mesoporous-silica induced doped carbon nanotube growth from metal–organic frameworks

Nanoscale ◽  
2018 ◽  
Vol 10 (13) ◽  
pp. 6147-6154 ◽  
Author(s):  
Huang Zhou ◽  
Daping He ◽  
Amiinu Ibrahim Saana ◽  
Jinlong Yang ◽  
Zhe Wang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Mesoporous Silica ◽  
Metal Organic Frameworks ◽  
Small Diameter ◽  
Metal Organic ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth ◽  
Co Doped

Small diameter cobalt and nitrogen co-doped carbon nanotubes (Co/N-CNTs) were grown from a mesoporous-silica (mSiO2) covered Co-based MOF (ZIF-67).

Patterned Carbon Nanotube Growth on Convex Cylindrical Stainless Steel Substrates for the Production of Coronary Stents

2016 ◽  
Author(s):  
Warren Robison ◽  
Brian Jensen ◽  
Anton Bowden
Keyword(s):  
Carbon Nanotubes ◽  
Stainless Steel ◽  
Carbon Nanotube ◽  
Standard Deviation ◽  
Coronary Stents ◽  
Free Standing ◽  
Type Pattern ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth ◽  
Steel Substrates

This paper reports research in fabrication of cylindrical stents using carbon-infiltrated carbon nanotubes (CI-CNT), a material with good hemocompatibility. We demonstrate growth of CI-CNT forests in patterned lines on a 3 mm diameter stainless steel (SS) rod. Lines were patterned parallel, at 7°, at 45°, and perpendicular relative to the axis of the rod. Minimal cracking was seen in the parallel and angled lines. Significant cracking was seen in the perpendicular lines and we attempted to characterize the cracking in order to correlate it to width of the lines and height of the forest. No correlation was found but the average uncracked length was determined to be 414 μm with a standard deviation of 67 μm. We also demonstrate successful growth with minimal cracking of CI-CNT forests in a zig-zag type pattern in an effort to further the possibility of creating a coronary stent utilizing CI-CNT. Some of the patterned samples were also removed from the cylindrical substrate, resulting in free-standing, patterned, cylindrical patterns made from CI-CNT.

Growth of Carbon Nanotubes on Copper Substrates Using a Nickel Thin Film Catalyst

2009 ◽  
Vol 1204 ◽  
Author(s):  
Gowtam Atthipalli ◽  
Prashant Kumta ◽  
Wei Wang ◽  
Rigved Epur ◽  
Prashanth H Jampani ◽  
...  
Keyword(s):  
Thin Film ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Nickel Catalyst ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Thin Film Catalyst ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth

AbstractCarbon nanotubes with their attractive properties, one-dimensional character, and their large aspect ratio are ideal candidates for a variety of applications including energy storage, sensing, nanoelectronics, among others. We have studied the growth of carbon nanotubes on copper substrates using a nickel thin film as a catalyst. The catalyst was sputtered in a chamber having a base pressure in the ultra-high-vacuum regime. By adjusting the sputtering parameters, the effects of the morphology and the thickness of the nickel catalyst on the growth of carbon nanotubes have also been investigated. Multiple hydrocarbon sources as carbon feedstock (methane, acetylene and xylene) and corresponding catalyst precursors and varying temperature conditions were used during the Chemical Vapor Deposition (CVD) process to understand and best determine the ideal conditions for carbon nanotube growth on copper. Correlation between the thickness of the thin film nickel catalyst and the carbon nanotube diameter is also presented in the study. Characterization techniques used to study the morphology of the CNTs grown on copper include SEM, TEM and HRTEM, Raman Spectroscopy

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