Carbon nanotubes have extraordinary strength and unique electrical properties. They are classified as single-walled or multi-walled nanotubes. Common synthesis methods are arc discharge, laser ablation, and chemical vapor deposition. Key milestones include the discovery of 18.5 cm long nanotubes and the thinnest freestanding single-walled nanotube of about 4.3 Angstroms in diameter. Carbon nanotubes have immense strength, are harder than diamond, and are excellent thermal and electrical conductors.
It contains information about Carbon nanotubes which are extensively used in nanotechnology for various puposes. It discusses various types of CNTs along with the three main ways to synthesize them. The three main ways are Arc Discharge, Laser Ablation and Chemical Vapour Deposition. It also discusses various applications os CNTs and their properties.
The document discusses carbon nanotubes, including their structure as rolled graphene sheets, properties like strength and conductivity, common synthesis methods like arc discharge and chemical vapor deposition, potential applications in electronics and medicine, and challenges for further development and commercialization like high production costs and concerns about toxicity.
Sumio Iijima is credited with discovering carbon nanotubes in 1991. Carbon nanotubes are cylindrical structures made of carbon atoms that have unique mechanical and electrical properties. There are two main types: single-walled nanotubes and multi-walled nanotubes. Carbon nanotubes have a variety of potential applications due to their extraordinary strength, thermal conductivity, and other properties.
Carbon nanotubes are allotropes of carbon that have a nanostructure that is a hollow cylinder of graphene. There are two main types: single-walled nanotubes consisting of a single layer of graphene and multi-walled nanotubes containing multiple layers of graphene. Carbon nanotubes are synthesized using methods such as arc discharge, laser ablation, and chemical vapor deposition. They are characterized using techniques like scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. Carbon nanotubes have remarkable mechanical, thermal, and electrical properties that make them promising for applications in materials science, electronics, and other fields.
Introduction to carbon nanotubes and their applicationsAnkit Kumar Singh
This document introduces carbon nanotubes and discusses their applications. It describes how carbon nanotubes are structured and the different types based on their chiral vector. Applications discussed include super-tough carbon nanotube fibers, nanotube flat panel displays, artificial muscles, nano tweezers, gas sensors, and liquid flow sensors. In particular, it notes that carbon nanotube composite fibers are tougher than steel or spider silk and can be woven into electronic textiles. It also shows how nanotubes efficiently emit electrons as field emitters and can be used as tiny rotors or to detect molecules for gas sensing.
Carbon nanotubes and their applications are discussed. There are several allotropes of carbon including diamond, graphite, buckminsterfullerene (C60), and single-walled carbon nanotubes. Carbon nanotubes are cylindrical forms of carbon that can be single-walled or multi-walled. They are composed of hexagonal networks of carbon atoms and have remarkable mechanical, thermal, and electrical properties. Common synthesis methods for carbon nanotubes include arc discharge, laser ablation, and chemical vapor deposition using metal catalysts.
This document discusses carbon nanotubes (CNTs), including their discovery, structure, properties, synthesis, applications, and future potential. Some key points:
- CNTs were discovered in 1991 and have a rolled-up graphene sheet structure that gives them unique mechanical and electrical properties.
- CNTs exhibit extraordinary strength and conductivity, with current-carrying capacity 1000 times higher than copper.
- Common synthesis methods are arc discharge, laser ablation, and chemical vapor deposition.
- Applications include energy storage, conductive composites, electronics, and more. Mass production is increasing and CNTs are already used in some products.
- CNTs show promise for applications across many industries
It contains information about Carbon nanotubes which are extensively used in nanotechnology for various puposes. It discusses various types of CNTs along with the three main ways to synthesize them. The three main ways are Arc Discharge, Laser Ablation and Chemical Vapour Deposition. It also discusses various applications os CNTs and their properties.
The document discusses carbon nanotubes, including their structure as rolled graphene sheets, properties like strength and conductivity, common synthesis methods like arc discharge and chemical vapor deposition, potential applications in electronics and medicine, and challenges for further development and commercialization like high production costs and concerns about toxicity.
Sumio Iijima is credited with discovering carbon nanotubes in 1991. Carbon nanotubes are cylindrical structures made of carbon atoms that have unique mechanical and electrical properties. There are two main types: single-walled nanotubes and multi-walled nanotubes. Carbon nanotubes have a variety of potential applications due to their extraordinary strength, thermal conductivity, and other properties.
Carbon nanotubes are allotropes of carbon that have a nanostructure that is a hollow cylinder of graphene. There are two main types: single-walled nanotubes consisting of a single layer of graphene and multi-walled nanotubes containing multiple layers of graphene. Carbon nanotubes are synthesized using methods such as arc discharge, laser ablation, and chemical vapor deposition. They are characterized using techniques like scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. Carbon nanotubes have remarkable mechanical, thermal, and electrical properties that make them promising for applications in materials science, electronics, and other fields.
Introduction to carbon nanotubes and their applicationsAnkit Kumar Singh
This document introduces carbon nanotubes and discusses their applications. It describes how carbon nanotubes are structured and the different types based on their chiral vector. Applications discussed include super-tough carbon nanotube fibers, nanotube flat panel displays, artificial muscles, nano tweezers, gas sensors, and liquid flow sensors. In particular, it notes that carbon nanotube composite fibers are tougher than steel or spider silk and can be woven into electronic textiles. It also shows how nanotubes efficiently emit electrons as field emitters and can be used as tiny rotors or to detect molecules for gas sensing.
Carbon nanotubes and their applications are discussed. There are several allotropes of carbon including diamond, graphite, buckminsterfullerene (C60), and single-walled carbon nanotubes. Carbon nanotubes are cylindrical forms of carbon that can be single-walled or multi-walled. They are composed of hexagonal networks of carbon atoms and have remarkable mechanical, thermal, and electrical properties. Common synthesis methods for carbon nanotubes include arc discharge, laser ablation, and chemical vapor deposition using metal catalysts.
This document discusses carbon nanotubes (CNTs), including their discovery, structure, properties, synthesis, applications, and future potential. Some key points:
- CNTs were discovered in 1991 and have a rolled-up graphene sheet structure that gives them unique mechanical and electrical properties.
- CNTs exhibit extraordinary strength and conductivity, with current-carrying capacity 1000 times higher than copper.
- Common synthesis methods are arc discharge, laser ablation, and chemical vapor deposition.
- Applications include energy storage, conductive composites, electronics, and more. Mass production is increasing and CNTs are already used in some products.
- CNTs show promise for applications across many industries
Carbon nanotubes are cylindrical nanostructures made entirely of carbon atoms. They have a length-to-diameter ratio of up to 132,000,000:1. There are two main types: single-walled nanotubes consisting of a single graphene cylinder, and multi-walled nanotubes containing multiple graphene cylinders. Carbon nanotubes were first discovered in the 1970s and were fully characterized in the early 1990s. They exhibit extraordinary strength and electrical conductivity and have a wide variety of potential applications, including in materials science, electronics, optics, and biomedical engineering.
CARBON NANOTUBES-TREATMENT AND FUNCTIONALIZATIONArjun K Gopi
Carbon nanotubes are fullerene-related structures consisting of graphene cylinders closed at either end with pentagonal rings. There are two main types: single-walled nanotubes (SWNTs), which have diameters around 1 nanometer, and multi-walled nanotubes (MWNTs) made of multiple concentric graphene cylinders. Functionalization of carbon nanotubes is important for applications and can occur through non-covalent interactions like wrapping of surfactants or polymers or through covalent bonding by attaching molecules to existing defects or through reactions to functionalize the graphene sidewalls. The document discusses different methods of non-covalent and covalent functionalization of carbon nanotubes.
This document discusses carbon nanotubes, including their discovery in the 1950s, classification as single-walled or multi-walled nanotubes, properties like strength and conductivity, common synthesis methods like arc discharge and chemical vapor deposition, and potential applications such as for solar cells, sporting goods, and neural networks. It also notes potential health risks from short carbon nanotubes and the need for further research on impacts.
Carbon Nanotubes and Their Methods of Synthesis tabirsir
This document discusses carbon nanotubes and their methods of synthesis. It begins by defining carbon nanotubes as sheets of graphite rolled into cylinders that can have single or multiple layers. It then discusses their extraordinary mechanical properties and classification based on chirality. Common synthesis methods are also summarized, including chemical vapor deposition, plasma enhanced CVD, arc discharge in a magnetic field, and laser ablation of metallic catalysts. Medical applications of carbon nanotubes are briefly mentioned at the end.
Carbon nanotubes are allotropes of carbon that exist as cylindrical structures with a high length-to-diameter ratio. They can be single-walled or multi-walled depending on the number of concentric cylinders. Carbon nanotubes have extraordinary properties including high strength, stiffness, thermal conductivity, and electrical conductivity. Due to these properties, carbon nanotubes show promise for applications in electronics, hydrogen storage, solar cells, biosensors, drug delivery, and more.
A seminar report summarizes carbon nanotubes, including their synthesis, types, and applications. It describes three main methods for synthesizing carbon nanotubes: plasma-based methods such as arc discharge; thermal methods such as chemical vapor deposition; and hydrothermal methods. It outlines the different types of carbon nanotubes including single-walled, multi-walled, nanotori, nanobuds, and nanonorns. Current applications discussed include materials, electronics and energy storage, with potential future applications in fields like biotechnology.
Carbon nanotubes properties and applicationsAMIYA JANA
Carbon nanotubes (CNTs) are cylindrical nanostructures made by rolling graphene sheets into hollow tubes with diameters as small as 0.7 nanometers. CNTs have extraordinary mechanical and thermal properties. They can be either metallic or semiconducting depending on their structure and chirality. CNTs show promise for applications in electronics, sensors, composites, medicine, and energy storage if production costs can be reduced and issues of purity and manipulation are addressed.
This document discusses carbon nanotubes. It describes carbon nanotubes as having a diameter as small as 1nm and being made of rolled graphene sheets. Carbon nanotubes can be single-walled, multi-walled, or double-walled. They have extraordinary properties including high tensile strength, electrical and thermal conductivity. Potential applications include conductive plastics, structural materials, electronics, and biosensors. Common fabrication methods are electric arc discharge, laser ablation, and chemical vapor deposition.
This document discusses carbon nanotubes, including their discovery in 1952, types (single-walled and multi-walled), structure, properties, synthesis methods, and potential applications. Carbon nanotubes have extraordinary strength and stiffness, along with high thermal and electrical conductivity. However, they can also be toxic and have crystallographic defects. The three main synthesis methods are arc discharge, laser ablation, and chemical vapor deposition. Carbon nanotubes show promise for applications in materials science, electronics, medicine, and other fields due to their unique properties at the nanoscale.
The document discusses carbon nanotubes, including their structure, types, and production methods. Carbon nanotubes are cylindrical tubes composed solely of carbon atoms. They can be single-walled or multi-walled, and have a diameter on the nanometer scale. Common production techniques include arc discharge, laser ablation, and chemical vapor deposition using a metal catalyst. Carbon nanotubes have exceptional mechanical and electrical properties and potential applications in materials, electronics, and biomedical fields.
This document discusses carbon nanotubes, their properties, synthesis, and applications in electronic devices. It describes that carbon nanotubes are cylindrical structures made of rolled graphene sheets that are only a few nanometers in width but can be many microns in length. They exist as single-walled nanotubes or multi-walled nanotubes. The document outlines different methods for synthesizing carbon nanotubes and reviews their applications, including uses in transparent conductive films, printable transistors, field emission, integrated circuits, fibers, and paper batteries. In conclusion, it states that carbon nanotubes are poised to replace silicon in miniaturizing electronic circuits and pushing beyond the theoretical limits of silicon transistors.
The document summarizes the inert gas condensation method for preparing nanoparticles. It involves evaporating a material and then rapidly condensing it using an inert gas to produce nanoparticles with controlled sizes in the range of 10-9 m. Process parameters like inert gas pressure, temperature, flow rate and evaporation rate can be adjusted to control the average particle size. This technique is used to produce a wide range of metallic, ceramic, and composite nanoparticles and offers advantages of size control and material flexibility, though high vacuum and agglomeration issues exist.
This document describes the arc discharge method for synthesizing nanomaterials. It discusses how an arc discharge works by thermionic emission to vaporize electrode materials and form a plasma. The document provides details on the experimental setup, conditions for producing single-walled carbon nanotubes, and applications of the arc discharge method such as synthesizing carbon nanotubes, metal nanoparticles, and nanowires.
Carbon nanotubes are cylindrical nanostructures made of rolled up graphene sheets with extraordinary mechanical and electrical properties. They can be single-walled or multi-walled depending on the number of concentric cylinders. Carbon nanotubes have a wide range of potential applications due to their strength, conductivity, and other properties including use in electronics, sensors, energy storage, and more. However, their toxicity must still be addressed before many applications.
This document discusses applications of carbon nanotubes for drug delivery systems. Carbon nanotubes have unique properties like high surface area and thermal conductivity that make them promising candidates for drug transport and delivery. They can be functionalized for biomedical applications through covalent and non-covalent methods. Carbon nanotubes show potential as drug carriers for cancer treatment, transdermal drug delivery, cardiac regulation, and tissue regeneration. Different synthesis techniques like arc discharge, laser ablation, and chemical vapor deposition are used to produce carbon nanotubes in large quantities.
This document provides an introduction to carbon nanotubes, including their structure, properties, growth methods, applications, and commercial aspects. It describes how carbon nanotubes are tubular forms of carbon that are only a few nanometers in diameter but can be several microns in length. Their properties, such as electrical conductivity, strength, and heat conduction, make them promising for applications like electronics, composites, and energy storage. Methods for growing carbon nanotubes include arc discharge, laser ablation, and chemical vapor deposition. The document concludes that carbon nanotubes have a variety of potential applications and are beginning to be commercialized by around 20 companies worldwide.
Carbon Nanotubes Properties and its ApplicationsArun Kumar
This document discusses carbon nanotubes. It defines a carbon nanotube as a tube-shaped material made of carbon that has a diameter on the nanometer scale, which is about 10,000 times smaller than a human hair. Carbon nanotubes are categorized as either single-walled or multi-walled. The document lists several applications of carbon nanotubes, including in thermal conductivity, energy storage, structural materials, fibers, biomedicine, filtration, electronics, and bioengineering. Several synthesis methods for carbon nanotubes are also described, such as arc discharge, laser ablation, chemical vapor deposition, and ball milling.
The document discusses various carbon allotropes beyond graphite and diamond, including fullerenes, graphene, buckypaper, and carbon nanotubes. Fullerenes are hollow spheres or tubes made of carbon, such as buckyballs. Graphene is a single layer of carbon atoms in a hexagonal lattice that is very strong yet conductive. Buckypaper is a thin sheet made of carbon aggregates. Carbon nanotubes are hollow cylinders of carbon that are very strong and stable. The document outlines various properties and applications of these carbon allotropes in areas like biotechnology, materials science, and medicine.
Analysis of buckling behaviour of functionally graded platesByju Vijayan
1. The document discusses the buckling behavior of functionally graded plates through two case studies.
2. The first case study analyzes the buckling of simply supported functionally graded rectangular plates under non-uniform in-plane compressive loading using classical plate theory. It finds that the critical buckling coefficient increases with the power law index and aspect ratio.
3. The second case study examines the buckling of imperfect functionally graded plates under in-plane compressive loading. It determines that the critical buckling load depends on factors like the load ratio, power law index, and amplitude of imperfection.
Carbon nanotubes are cylindrical nanostructures made entirely of carbon atoms. They have a length-to-diameter ratio of up to 132,000,000:1. There are two main types: single-walled nanotubes consisting of a single graphene cylinder, and multi-walled nanotubes containing multiple graphene cylinders. Carbon nanotubes were first discovered in the 1970s and were fully characterized in the early 1990s. They exhibit extraordinary strength and electrical conductivity and have a wide variety of potential applications, including in materials science, electronics, optics, and biomedical engineering.
CARBON NANOTUBES-TREATMENT AND FUNCTIONALIZATIONArjun K Gopi
Carbon nanotubes are fullerene-related structures consisting of graphene cylinders closed at either end with pentagonal rings. There are two main types: single-walled nanotubes (SWNTs), which have diameters around 1 nanometer, and multi-walled nanotubes (MWNTs) made of multiple concentric graphene cylinders. Functionalization of carbon nanotubes is important for applications and can occur through non-covalent interactions like wrapping of surfactants or polymers or through covalent bonding by attaching molecules to existing defects or through reactions to functionalize the graphene sidewalls. The document discusses different methods of non-covalent and covalent functionalization of carbon nanotubes.
This document discusses carbon nanotubes, including their discovery in the 1950s, classification as single-walled or multi-walled nanotubes, properties like strength and conductivity, common synthesis methods like arc discharge and chemical vapor deposition, and potential applications such as for solar cells, sporting goods, and neural networks. It also notes potential health risks from short carbon nanotubes and the need for further research on impacts.
Carbon Nanotubes and Their Methods of Synthesis tabirsir
This document discusses carbon nanotubes and their methods of synthesis. It begins by defining carbon nanotubes as sheets of graphite rolled into cylinders that can have single or multiple layers. It then discusses their extraordinary mechanical properties and classification based on chirality. Common synthesis methods are also summarized, including chemical vapor deposition, plasma enhanced CVD, arc discharge in a magnetic field, and laser ablation of metallic catalysts. Medical applications of carbon nanotubes are briefly mentioned at the end.
Carbon nanotubes are allotropes of carbon that exist as cylindrical structures with a high length-to-diameter ratio. They can be single-walled or multi-walled depending on the number of concentric cylinders. Carbon nanotubes have extraordinary properties including high strength, stiffness, thermal conductivity, and electrical conductivity. Due to these properties, carbon nanotubes show promise for applications in electronics, hydrogen storage, solar cells, biosensors, drug delivery, and more.
A seminar report summarizes carbon nanotubes, including their synthesis, types, and applications. It describes three main methods for synthesizing carbon nanotubes: plasma-based methods such as arc discharge; thermal methods such as chemical vapor deposition; and hydrothermal methods. It outlines the different types of carbon nanotubes including single-walled, multi-walled, nanotori, nanobuds, and nanonorns. Current applications discussed include materials, electronics and energy storage, with potential future applications in fields like biotechnology.
Carbon nanotubes properties and applicationsAMIYA JANA
Carbon nanotubes (CNTs) are cylindrical nanostructures made by rolling graphene sheets into hollow tubes with diameters as small as 0.7 nanometers. CNTs have extraordinary mechanical and thermal properties. They can be either metallic or semiconducting depending on their structure and chirality. CNTs show promise for applications in electronics, sensors, composites, medicine, and energy storage if production costs can be reduced and issues of purity and manipulation are addressed.
This document discusses carbon nanotubes. It describes carbon nanotubes as having a diameter as small as 1nm and being made of rolled graphene sheets. Carbon nanotubes can be single-walled, multi-walled, or double-walled. They have extraordinary properties including high tensile strength, electrical and thermal conductivity. Potential applications include conductive plastics, structural materials, electronics, and biosensors. Common fabrication methods are electric arc discharge, laser ablation, and chemical vapor deposition.
This document discusses carbon nanotubes, including their discovery in 1952, types (single-walled and multi-walled), structure, properties, synthesis methods, and potential applications. Carbon nanotubes have extraordinary strength and stiffness, along with high thermal and electrical conductivity. However, they can also be toxic and have crystallographic defects. The three main synthesis methods are arc discharge, laser ablation, and chemical vapor deposition. Carbon nanotubes show promise for applications in materials science, electronics, medicine, and other fields due to their unique properties at the nanoscale.
The document discusses carbon nanotubes, including their structure, types, and production methods. Carbon nanotubes are cylindrical tubes composed solely of carbon atoms. They can be single-walled or multi-walled, and have a diameter on the nanometer scale. Common production techniques include arc discharge, laser ablation, and chemical vapor deposition using a metal catalyst. Carbon nanotubes have exceptional mechanical and electrical properties and potential applications in materials, electronics, and biomedical fields.
This document discusses carbon nanotubes, their properties, synthesis, and applications in electronic devices. It describes that carbon nanotubes are cylindrical structures made of rolled graphene sheets that are only a few nanometers in width but can be many microns in length. They exist as single-walled nanotubes or multi-walled nanotubes. The document outlines different methods for synthesizing carbon nanotubes and reviews their applications, including uses in transparent conductive films, printable transistors, field emission, integrated circuits, fibers, and paper batteries. In conclusion, it states that carbon nanotubes are poised to replace silicon in miniaturizing electronic circuits and pushing beyond the theoretical limits of silicon transistors.
The document summarizes the inert gas condensation method for preparing nanoparticles. It involves evaporating a material and then rapidly condensing it using an inert gas to produce nanoparticles with controlled sizes in the range of 10-9 m. Process parameters like inert gas pressure, temperature, flow rate and evaporation rate can be adjusted to control the average particle size. This technique is used to produce a wide range of metallic, ceramic, and composite nanoparticles and offers advantages of size control and material flexibility, though high vacuum and agglomeration issues exist.
This document describes the arc discharge method for synthesizing nanomaterials. It discusses how an arc discharge works by thermionic emission to vaporize electrode materials and form a plasma. The document provides details on the experimental setup, conditions for producing single-walled carbon nanotubes, and applications of the arc discharge method such as synthesizing carbon nanotubes, metal nanoparticles, and nanowires.
Carbon nanotubes are cylindrical nanostructures made of rolled up graphene sheets with extraordinary mechanical and electrical properties. They can be single-walled or multi-walled depending on the number of concentric cylinders. Carbon nanotubes have a wide range of potential applications due to their strength, conductivity, and other properties including use in electronics, sensors, energy storage, and more. However, their toxicity must still be addressed before many applications.
This document discusses applications of carbon nanotubes for drug delivery systems. Carbon nanotubes have unique properties like high surface area and thermal conductivity that make them promising candidates for drug transport and delivery. They can be functionalized for biomedical applications through covalent and non-covalent methods. Carbon nanotubes show potential as drug carriers for cancer treatment, transdermal drug delivery, cardiac regulation, and tissue regeneration. Different synthesis techniques like arc discharge, laser ablation, and chemical vapor deposition are used to produce carbon nanotubes in large quantities.
This document provides an introduction to carbon nanotubes, including their structure, properties, growth methods, applications, and commercial aspects. It describes how carbon nanotubes are tubular forms of carbon that are only a few nanometers in diameter but can be several microns in length. Their properties, such as electrical conductivity, strength, and heat conduction, make them promising for applications like electronics, composites, and energy storage. Methods for growing carbon nanotubes include arc discharge, laser ablation, and chemical vapor deposition. The document concludes that carbon nanotubes have a variety of potential applications and are beginning to be commercialized by around 20 companies worldwide.
Carbon Nanotubes Properties and its ApplicationsArun Kumar
This document discusses carbon nanotubes. It defines a carbon nanotube as a tube-shaped material made of carbon that has a diameter on the nanometer scale, which is about 10,000 times smaller than a human hair. Carbon nanotubes are categorized as either single-walled or multi-walled. The document lists several applications of carbon nanotubes, including in thermal conductivity, energy storage, structural materials, fibers, biomedicine, filtration, electronics, and bioengineering. Several synthesis methods for carbon nanotubes are also described, such as arc discharge, laser ablation, chemical vapor deposition, and ball milling.
The document discusses various carbon allotropes beyond graphite and diamond, including fullerenes, graphene, buckypaper, and carbon nanotubes. Fullerenes are hollow spheres or tubes made of carbon, such as buckyballs. Graphene is a single layer of carbon atoms in a hexagonal lattice that is very strong yet conductive. Buckypaper is a thin sheet made of carbon aggregates. Carbon nanotubes are hollow cylinders of carbon that are very strong and stable. The document outlines various properties and applications of these carbon allotropes in areas like biotechnology, materials science, and medicine.
Analysis of buckling behaviour of functionally graded platesByju Vijayan
1. The document discusses the buckling behavior of functionally graded plates through two case studies.
2. The first case study analyzes the buckling of simply supported functionally graded rectangular plates under non-uniform in-plane compressive loading using classical plate theory. It finds that the critical buckling coefficient increases with the power law index and aspect ratio.
3. The second case study examines the buckling of imperfect functionally graded plates under in-plane compressive loading. It determines that the critical buckling load depends on factors like the load ratio, power law index, and amplitude of imperfection.
This document provides an overview of nanotechnology including its history, definition, and applications. It discusses the following key points:
- Nanotechnology involves engineering at the molecular scale between 1 to 100 nanometers as well as manipulating and controlling matter on an atomic and molecular scale.
- Some applications of nanotechnology discussed include using nanomachines like nanoimpellers to target cancer cells, developing nanobots, improving electronics by reducing transistor size, and delivering drugs using nanoparticles.
- In medicine, nanotechnology is being used for targeted drug delivery, therapies like buckyballs and nanoshells, and developing anti-microbial techniques with nanoparticle creams and cell repairs from nanorobots.
H20 & Co. has developed carbon nanotube membranes that provide a more cost-efficient way to remove chemicals and infectious agents from water. The membranes are made of single-walled or multi-walled carbon nanotubes that are less than 1 nm in diameter, allowing water to pass through while filtering out over 95% of ions and bacteria/viruses. The membranes provide clean, desalinated water at a lower cost than other filtration methods, with faster filtration rates and a lifespan of 2-3 years. The global market for nanofiltration membranes is growing significantly due to increasing water shortages, regulations, and demand for clean water.
This document provides an overview of nanotechnology and its history. It discusses key terms like nanoscale and nanotechnology. Some important developments include the discovery of buckyballs in 1980 and carbon nanotubes in 1991. The document also outlines several types of nanotechnology like nano-materials, nano-electronics, nano-robotics and their applications. Nanotechnology is seen as having great potential impacts across many fields like engineering, electronics, medicine and more.
Nanotechnology ppt from Top Nanotechnology Companies NANOSUSTENTABLE global directory. The basics of nanotechnology. What is nanotechnology and what is its role in aviation and aerospace industry?
This document discusses nanotechnology and its applications. It begins with an introduction to nanotechnology, defining a nanometer and describing how nanotechnology works at the molecular scale. It then outlines several key applications of nanotechnology, including improving medicine through targeted drug delivery and artificial organs, enabling more powerful supercomputing through molecular circuits, and using nanotechnology to clean the environment and purify water and air. The document provides an overview of the goals, pioneers, approaches, techniques and many potential benefits of nanotechnology.
This presentation discusses functionally graded materials (FGMs). FGMs are composites with a gradual, continuous transition in composition and structure. They are classified as thin FGMs consisting of thin surface coatings, or bulk FGMs consisting of larger volumes. Common processing techniques for thin FGMs include vapor deposition and plasma spraying, while bulk FGMs can be made using powder metallurgy or centrifugal casting. FGMs have a variety of applications due to properties like resistance to delamination and high impact/abrasion resistance, and are used in industries such as aerospace, defense, energy and medicine.
This document outlines a student's workplan to study the fracture of functionally graded materials. The plan includes conducting a literature review to identify gaps and objectives, modeling the material and analyzing it using software, performing parametric studies on properties like reinforcement size and volume fractions, and submitting a final report. Experimental results are also presented on a photoelastic model that show stress distributions and crack propagation under loading. Numerical finite element modeling is found to match the experimental photoelastic results to within 5-8 percent.
This document discusses applications of nanotechnology including nanocells, carbon nanotubes, and molecular electronics. Nanocells are self-assembled networks of metallic particles that act as programmable switches. Carbon nanotubes are rolled sheets of carbon that can be semiconductors or metals and are strong candidates for nanowires. Potential applications highlighted include using carbon nanotubes for transistors, fuel cells, and simulation. Other applications discussed are nanobridge devices, nanoscale transistors, components for quantum computers, nanophotonic devices, and nanobiochips for drug discovery.
Digital jewelry embeds technology like microphones, displays, and wireless capabilities into jewelry items. An IBM prototype used several connected jewelry pieces like a necklace with a microphone and bracelet with a display to perform mobile phone functions. Digital jewelry can be used as smart watches with screens, ear rings that function as speakers, or rings with buttons. This bridges the physical and digital worlds and technology may become more integrated with the human body in the future. However, digital jewelry also has limitations like small displays, potential health risks from rays, expensive costs, and non-rechargeable batteries.
Nanotechnology involves processes at the molecular and nano-length scale. It has numerous applications in pharmacy, including as drug delivery systems using liposomes, dendrimers, nanoparticles, and nanotubes. Pharmaceutical nanotechnology provides nano-materials for tissue engineering and nano-devices like biosensors. Nano-materials are used for drug encapsulation, implants, and scaffolds. Nano-devices include biosensors, detectors, and potential "nano-robots". Current applications include medicine, tissue engineering, diagnostics, and imaging enhancement. Future prospects may include intelligent machines that detect, treat, and monitor disease simultaneously.
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Researchers have always tried to build a device capable of seeing people through walls. However, previous efforts to develop such a system have involved the use of expensive and bulky radar technology that uses a part of the electromagnetic spectrum only available to the military. Now a system is being developed by Dina Katabi and Fadel Adib, could give all of us the ability to spot people in different rooms using low-cost Wi-Fi technology. The device is low-power, portable and simple enough for anyone to use, to give people the ability to see through walls and closed doors. The system, called “Wi-Vi,” stands for "Wi-Fi" and "vision." is based on a concept similar to radar and sonar imaging. But in contrast to radar and sonar, it transmits a low-power Wi-Fi signal and uses its reflections to track moving humans. It can do so even if the humans are in closed rooms or hiding behind a wall.
Simple definition for Wi-Vi is, as a Wi-Fi signal is transmitted at a wall, a portion of the signal penetrates through it, reflecting off any humans on the other side. However, only a tiny fraction of the signal makes it through to the other room, with the rest being reflected by the wall, or by other objects. Wi-Vi cancels out all these other reflections, and keeps only those from the moving human body. Previous work demonstrated that the subtle reflections of wireless inter signals bouncing off a human could be used to track that person's movements, but those previous experiments either required that a wireless router was already in the room of the person being tracked. Wi-Fi signals and recent advances in MIMO communications are used to build a device that can capture the motion of humans behind a wall and in closed rooms. Law enforcement personnel can use the device to avoid walking into an ambush, and minimize casualties in standoffs and hostage situations. Emergency responders can use it to see through rubble and collapsed structures. Ordinary users can leverage the device for gaming, intrusion detection, privacy-enhanced monitoring of children and elderly, or personal security when stepping into dark alleys and unknown places.
The concept underlying seeing through opaque obstacles is similar to radar and sonar imaging. Specifically, when faced with a non-metallic wall, a fraction of the RF signal would traverse the wall, reflect off objects and humans, and come back imprinted with a signature of what is inside a closed room. By capturing these reflections, we can image objects behind a wall.
Wi-Vi is a see-through-wall technology that is low-bandwidth, low-power, compact, and accessible to non-military entities. Wi-Vi is a see-through-wall device that employs Wi-Fi signals in the 2.4 GHz ISM band.
Wi-Vi is a technique developed by researchers at MIT that uses standard Wi-Fi signals to detect motion behind walls. It transmits two Wi-Fi waves that cancel each other when reflecting off static objects but not moving objects. This allows it to determine the number and locations of moving humans in a closed room without any devices on the other side of the wall. It was implemented with off-the-shelf USRP radios and shown to detect humans moving behind walls up to 8 inches thick. Wi-Vi has applications for search and rescue, security, and interactive interfaces and operates within the unlicensed Wi-Fi spectrum.
This document describes a 5 pen pc technology called P-ISM. P-ISM consists of 5 functions: a CPU pen, camera, virtual keyboard, visual output, and cellular phone. It uses various wireless technologies like Bluetooth and WiFi to connect multiple pens together and to the internet. The pens allow users to project a keyboard and monitor onto any flat surface and use it like a portable computer. While portable and allowing ubiquitous computing, challenges remain regarding its cost, battery life, and keyboard design.
Google announced in 2014 that it was developing a smart contact lens with a wireless chip and sensor to measure glucose levels in tears every second. The lens would also have an LED that blinks to indicate if blood sugar is too high or too low. Shortly after, Novartis partnered with Google to develop products using Google's smart lens technology.
The document discusses digital pens, which allow handwritten notes to be converted to digital form. A digital pen functions similarly to a regular pen but contains additional components like an optical reader, wireless transmitter, and battery. It records handwriting as coordinates and transmits the data to a computer via Bluetooth. Digital pens offer advantages like the ability to organize and back up notes digitally. They can also record audio and download apps. In conclusion, digital pens provide a cost-effective way to integrate handwriting with digital tools and workflows.
This document provides information about touchscreens and touchless touchscreen technology. It discusses the history and development of touchscreen technology. It describes how traditional touchscreens work using touch sensors, controllers, and drivers. It then introduces touchless touchscreen technology, which allows interaction through hand gestures in front of the screen rather than physical touch. Examples of touchless touchscreen products include touchless monitors, touch walls that can turn entire walls into touch interfaces using projected screens, and gesture-based user interfaces. The document explores several companies developing touchless technology solutions.
This document discusses digital jewelry, which combines fashion jewelry with embedded computing technology. Digital jewelry devices could include earrings with speakers, a necklace with a microphone, a ring with LEDs to indicate calls, and a bracelet with a small display. The technology allows for a wireless wearable computer using Bluetooth. Issues include small displays, potential health risks from radiation, water damage risks, and high costs, but digital jewelry may eventually replace standalone computers by integrating all necessary functions into fashionable items that are easy to carry everywhere.
Research in Mechatronics and Cyber - MixMecatronics is
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The document provides information about carbon nanotubes, including:
1) It discusses various methods for synthesizing carbon nanotubes, including arc discharge, laser ablation, high pressure carbon monoxide (HiPco), and chemical vapor deposition.
2) It describes different types of carbon nanotubes, including single-walled nanotubes, multi-walled nanotubes, and other structures like torus, nanobuds, and graphenated carbon nanotubes.
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- Potential applications of carbon nanotubes include use in composite materials, electronics, energy storage, sensors, and biomedical devices due to their unique mechanical and electrical properties at the nanoscale.
- Carbon nanotubes were discovered accidentally in the 1990s and have properties that could revolutionize technology. They are sheets of graphene rolled into cylindrical shapes that are only a few nanometers wide but can be hundreds of micrometers long.
- Carbon nanotubes are incredibly strong yet lightweight. A single-walled carbon nanotube can be up to 100 times stronger than steel relative to its thickness. They also conduct heat and electricity very well.
- Potential applications of carbon nanotubes include use in space elevators, hydrogen fuel cells, artificial muscles, electronics, sensors, and as reinforcements in composite materials. They are being researched for uses in fields like energy storage, medicine, and electronics.
Carbon nanotubes were first discovered in 1952 by Radushkevich and Lukyanovich, although their structure and properties were not fully characterized until later. Several methods have been used to synthesize carbon nanotubes since the 1970s, including arc discharge, laser ablation, and chemical vapor deposition. Carbon nanotubes exist in single-walled and multi-walled forms and have a variety of properties that make them suitable for applications such as electronics, optics, energy storage and more.
Carbon nanotube is an allotrope of carbon and it is widely used in many Research and Development companies. The presentation will help students to get some idea on this topic.
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This document discusses carbon nanotubes and their history and discovery. It begins by providing background on carbon nanotubes, describing their cylindrical nanostructure and how they are made by rolling graphene sheets into cylinders. It then discusses the history and discovery of carbon nanotubes, including the discovery of fullerenes in 1985 and carbon nanotubes themselves in 1991 by Sumio Iijima. The document concludes by classifying the two main types of carbon nanotubes as single-walled and multi-walled nanotubes.
This document provides an overview of nanomaterials and carbon nanotubes. It discusses how nanomaterials are materials with sizes between 1 to 100 nm that exhibit unique properties. Carbon nanotubes are nanomaterials made of rolled graphene sheets that have excellent mechanical and electrical properties. The document outlines several methods for synthesizing carbon nanotubes including high pressure carbon monoxide deposition and chemical vapor deposition. It then discusses important properties and applications of carbon nanotubes such as their strength, conductivity, and use as reinforcements in composites.
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This document provides an overview of carbon nanotubes, including their properties, types (single-walled vs multi-walled), methods of synthesis (arc discharge, laser ablation, chemical vapor deposition), applications, challenges and future outlook. Carbon nanotubes have extraordinary strength and unique electrical properties. They show promise for applications in electronics, optics, energy storage and more, but challenges remain in controlling their growth and assembly at scale.
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This document provides information about carbon nanotubes. It begins with an acknowledgement and introduction section describing carbon nanotubes. It then discusses the history, chemistry, types (single-walled and multi-walled), methods of preparation (arc evaporation, laser vaporization, chemical vapor deposition), electrical and thermal properties, defects, and applications (water filtration, strengthening materials, capacitors, bone repair, displays, energy storage). It also notes potential health hazards from inhalation of short carbon nanotubes.
This document provides an overview of carbon nanotubes. It begins with a brief introduction describing carbon nanotubes as revolutionary materials discovered by accident that will significantly influence society. The document then covers the history of carbon nanotube discovery and various synthesis methods. Key points about the structure and properties of carbon nanotubes like their mechanical strength and electrical properties are summarized. Finally, potential applications of carbon nanotubes in areas like gas storage, sensors, and SPM probes are outlined.
This document provides an introduction to carbon nanotubes including their history, structure, and production methods. Some key points:
- Carbon nanotubes were discovered accidentally in the 1950s but interest grew in the 1990s with the ability to produce nearly perfect multi-walled carbon nanotubes as byproducts.
- Carbon nanotubes have a unique structure of rolled graphene sheets that allows them to exist as single-walled or multi-walled tubes. This structure gives them extraordinary mechanical and electrical properties.
- Common production methods include electric arc discharge, laser ablation, chemical vapor deposition, and high pressure carbon monoxide processes. Each method uses a carbon source and sometimes a metal catalyst to help synt
Carbon nanotubes are cylindrical carbon molecules that exhibit extraordinary properties. They can be single-walled or multi-walled depending on the number of coaxial layers of graphite. Carbon nanotubes are very strong, light, and can be metallic or semiconducting depending on their structure. They are synthesized through arc discharge, laser ablation, or chemical vapor deposition methods.
Carbon nanotubes are hollow cylindrical structures made of carbon atoms that were discovered in 1991. They exist in different forms depending on how the graphene is rolled up, and have extraordinary strength and conductive properties. Potential applications include use in electronics, optics, energy storage and generation, and advanced materials. Significant challenges remain in controlling nanotube structure and properties at scale for widespread applications.
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Seminar report on Carbon Nanotubes
1. CONTENTS
1. INTRODUCTION
2. HISTORY
3. DISCOVERY
4. CLASSIFICATION OF CARBON NANOTUBES
5. SYNTHESIS OF CARBON NANOTUBES
6. MILESTONES IN CNT EVOLUTION
7. PROPERTIES OF CNT’S
8. ADVANTAGES
9. DISADVANTAGES
10. APPLICATIONS
11. CHALLENGES
12. CONCLUSION
13. REFRENCES
2. 1. INTRODUCTION
Carbon nanotubes (CNTs) take the form of cylindrical carbon molecules and have novel
properties that make them potentially useful in a wide variety of applications in
nanotechnology, electronics, optics, and other fields of materials science. They exhibit
extraordinary strength and unique electrical properties, and are efficient conductors of heat.
Inorganic nanotubes have also been synthesized.
Manufacturing a nanotube is dependent on applied quantum chemistry, specifically, orbital
hybridization. Nanotubes are composed entirely of sp2 bonds, similar to those of graphite.
This bonding structure, stronger than the sp3 bonds found in diamond, provides the
molecules with their unique strength. Nanotubes naturally align themselves into "ropes" held
together by Van der Waals forces. Under high pressure, nanotubes can merge together,
trading some sp2 bonds for sp3 bonds, giving great possibility for producing strong,
unlimited-length wires through high-pressure nanotube linking.
Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure.
Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1,
significantly larger than for any other material. These cylindrical carbon molecules have
unusual properties, which are valuable for nanotechnology, electronics, optics and other
fields of materials science and technology. In particular, owing to their extraordinary thermal
conductivity and mechanical and electrical properties, carbon nanotubes find applications as
additives to various structural materials. For instance, nanotubes form a tiny portion of the
material(s) in some (primarily carbon fiber) baseball bats, golf clubs, or car parts.
Nanotubes are members of the fullerene structural family. Their name is derived from their
long, hollow structure with the walls formed by one-atom-thick sheets of carbon, called
graphene. These sheets are rolled at specific and discrete ("chiral") angles and the
combination of the rolling angle and radius decides the nanotube properties; for example,
whether the individual nanotube shell is a metal or semiconductor.
Nanotubes are categorized as single-walled nanotubes (SWNTs) and multi-walled nanotubes
(MWNTs). Individual nanotubes naturally align themselves into "ropes" held together by van
der Waals forces, more specifically, pi-stacking.
Applied quantum chemistry, specifically, orbital hybridization best describes chemical
bonding in nanotubes. The chemical bonding of nanotubes is composed entirely of sp2 bonds,
similar to those of graphite. These bonds, which are stronger than the sp3 bonds found in
alkanes and diamond, provide nanotubes with their unique strength.
3. 2. HISTORY
In 1952 L. V. Radushkevich and V. M. Lukyanovich published clear images of 50 nanometer
diameter tubes made of carbon in the Soviet Journal of Physical Chemistry. This discovery
was largely unnoticed, as the article was published in the Russian language, and Western
scientists' access to Soviet press was limited during the Cold War. It is likely that carbon
nanotubes were produced before this date, but the invention of the transmission electron
microscope (TEM) allowed direct visualization of these structures.
Carbon nanotubes have been produced and observed under a variety of conditions prior to
1991. A paper by Oberlin, Endo, and Koyama published in 1976 clearly showed hollow
carbon fibers with nanometer-scale diameters using a vapor-growth technique. Additionally,
the authors show a TEM image of a nanotube consisting of a single wall of graphene. Later,
Endo has referred to this image as a single-walled nanotube.
In 1979, John Abrahamson presented evidence of carbon nanotubes at the 14th Biennial
Conference of Carbon at Pennsylvania State University. The conference paper described
carbon nanotubes as carbon fibers that were produced on carbon anodes during arc discharge.
A characterization of these fibers was given as well as hypotheses for their growth in a
nitrogen atmosphere at low pressures.
In 1981, a group of Soviet scientists published the results of chemical and structural
characterization of carbon nanoparticles produced by a thermocatalytical disproportionation
of carbon monoxide. Using TEM images and XRD patterns, the authors suggested that their
“carbon multi-layer tubular crystals” were formed by rolling graphene layers into cylinders.
They speculated that by rolling graphene layers into a cylinder, many different arrangements
of graphene hexagonal nets are possible. They suggested two possibilities of such
arrangements: circular arrangement (armchair nanotube) and a spiral, helical arrangement
(chiral tube).
3. DISCOVERY
They were discovered In 1991 by the Japanese electron microscopist SUMIO IIJIMA NEC
Laboratory in Tsukuba-- used high-resolution transmission electron microscopy to observe
carbon nanotubes, And into the awareness of the scientific community. Iijima's discovery of
multi-walled carbon nanotubes in the insoluble material of arc-burned graphite rods in 1991
and Mintmire, Dunlap, and White's independent prediction that if single-walled carbon
nanotubes could be made, then they would exhibit remarkable conducting properties helped
create the initial buzz that is now associated with carbon nanotubes. Nanotube research
accelerated greatly following the independent discoveries by Bethune at IBM and Iijima at
NEC of single-walled carbon nanotubes and methods to specifically produce them by adding
transition-metal catalysts to the carbon in an arc discharge. The arc discharge technique was
well-known to produce the famed Buckminster fullerene on a preparative scale, and these
results appeared to extend the run of accidental discoveries relating to fullerenes. The original
observation of fullerenes in mass spectrometry was not anticipated, and the first massproduction technique by Krätschmer and Huffman was used for several years before realizing
that it produced fullerenes.
4. 4. CLASSIFICATION OF CARBON NANOTUBES
Carbon nanotubes are mainly classified into two :1. Single-walled Nanotubes (SWNTS);
2. Multi-walled Nanotubes (MWNTS).
4.1 SINGLE-WALLED NANOTUBES (SWNTS)
• A single-walled carbon nanotube (SWNT) may be thought of as a single atomic layer thick
sheet of graphite (called graphene) rolled into a seamless cylinder.
• Most single-walled nanotubes (SWNT) have a diameter of close to 1 nanometre, with a tube
length that can be many millions of times longer.
• Single-walled nanotubes are an important variety of carbon nanotube because they exhibit
electric properties that are not shared by the multi-walled carbon nanotube (MWNT) variants.
Single walled CNTS (Graphical Representation)
5. 4.2 MULTI-WALLED NANOTUBES (MWNT)
1.
Multi-walled nanotubes (MWNT) consist of multiple rolled layers (concentric
tubes) of graphite.
2.
There are two models which can be used to describe the structures of multi-walled
nanotubes.
3.
In the Russian Doll model, sheets of graphite are arranged in concentric cylinders.
4.
In the Parchment model, a single sheet of graphite is rolled in around itself,
resembling a scroll of parchment or a rolled newspaper.(The Russian Doll structure
is observed more commonly).
5.
The telescopic motion ability of inner shells and their unique mechanical properties
will permit the use of multi-walled nanotubes as main movable arms in coming
Nano mechanical devices.
MULTI-WALLED CNT
6. 4.3 OTHER CARBON NANOTUBE STRUCTURES
1. Torus :Carbon nanotube bent into a torus (doughnut shape).Nanotori are predicted to have
many unique properties, such as magnetic moments 1000 times larger than
previously expected for certain specific radii. Properties such as magnetic moment,
thermal stability, etc. vary widely depending on radius of the torus and radius of the
tube.
2. Nanobud :Carbon Nanobud are a newly created material combining two previously discovered
allotropes of carbon: carbon nanotubes and fullerenes. In this new material,
fullerene-like "buds" are covalently bonded to the outer sidewalls of the underlying
carbon. They good field emitters. In composite materials, the attached fullerene
molecules may function as molecular anchors preventing slipping of the nanotubes,
thus improving the composite’s mechanical properties.
7. 3. GRAPHENATED CARBON NANOTUBES (G-CNTS) :Graphenated CNTs are a relatively new hybrid that combines graphitic foliates grown along
the sidewalls of multi walled or bamboo style CNTs use in super capacitor applications.
4. PEAPOD :
A Carbon peapod] is a novel hybrid carbon material which traps fullerene inside a carbon
nanotube.
5. CUP-STACKED CARBON NANOTUBES
CSCNTs exhibit semiconducting behaviors due to the stacking microstructure of graphene
layers.
6. NITROGEN DOPED CARBON NANOTUBES
N-doping provides defects in the walls of CNT's allowing for Li ions to diffuse into inter-wall
space. It also increases capacity by providing more favorable bind of N-doped sites. N-CNT's
are also much more reactive to metal oxide nanoparticle deposition which can further
enhance storage capacity, especially in anode materials for Li-ion batteries. However Boron
doped nanotubes have been shown to make batteries with triple capacity.
8. 5. SYNTHESIS OF CARBON NANOTUBES
Techniques have been developed to produce nanotubes, including arc discharge, laser ablation
and chemical vapor deposition (CVD). Most of these processes take place in vacuum or with
process gases. CVD growth of CNTs can take place in vacuum or at atmospheric pressure.
Large quantities of nanotubes can be synthesized by these methods; advances in catalysis and
continuous growth processes are making CNTs more commercially viable.
SWNTs and MWNTs are usually made by carbon-arc discharge, laser ablation of carbon, or
chemical vapor deposition (typically on catalytic particle). Nanotube diameters range from
0.4 to 3 nm for SWNTs and from 1.4 to at least 100 nm for MWNTs. Nanotube properties
can thus be tuned by changing the diameter. Unfortunately, SWNTs are presently produced
only on a small scale and are extremely expensive. All currently known synthesis methods
for SWNTs result in major concentrations of impurities. These impurities are typically
removed by acid treatment, which introduces other impurities, can degrade nanotube length
and perfection, and adds to nanotube cost.
MWNTs produced catalytically by gas-phase pyrolysis, like the Hyperion nanotubes, have
high defect densities compared to those produced by the more expensive carbon- arc process.
9. 5.1 ARC DISCHARGE METHOD
CNT production requires 3 elements,
1. Carbon feed.
2. Metal catalyst.
3. Heat
The nanotubes were initially discovered using this technique; it has been the most widelyused method of nanotube synthesis.
1. Two Graphite electrodes placed in an inert Helium atmosphere.
2. When DC current is passed anode is consumed and material forms on cathode.
3. For SWNT mixed metal catalyst is inserted into anode
4. Pure iron catalyst + Hydrogen-inert gas mixture gives 20 to 30cm long tube
10. 5.2 LASER ABLATION
1.
In the laser ablation process, a pulsed laser vaporizes a graphite target in a hightemperature reactor while an inert gas is bled into the chamber.
2. Nanotubes develop on the cooler surfaces of the reactor as the vaporized carbon
condenses.
3. A water-cooled surface may be included in the system to collect the nanotubes.
4. The laser ablation method yields around 70% and produces primarily single-walled
carbon nanotubes with a controllable diameter determined by the reaction
temperature.
5. It is more expensive than either arc discharge or chemical vapor deposition.
11. 5.3 CHEMICAL VAPOR DEPOSITION (CVD)
# During CVD, a substrate is prepared with a layer of metal catalyst articles, most
commonly nickel, cobalt, iron, or a combination.
# The diameters of the nanotubes that are to be grown are related to the size of the metal
particles.
# The substrate is heated to approximately 700°c.
# To initiate the growth of nanotubes, two gases are bled into the reactor: a process gas
(such as ammonia, nitrogen or hydrogen) and a carbon-containing gas (such as acetylene,
ethylene, ethanol or methane).
# Nanotubes grow at the sites of the metal catalyst;
# The carbon-containing gas is broken apart at the surface of the catalyst particle, and the
carbon is transported to the edges of the particle, where it forms the nanotubes.
12. 6. MILESTONES IN CNT EVOLUTION
The observation of the longest carbon nanotubes (18.5 cm long) was reported in 2009. These
nanotubes were grown on Si substrates using an improved chemical vapor deposition (CVD)
method and represent electrically uniform arrays of single-walled carbon nanotubes.
The shortest carbon nanotube is the organic compound cycloparaphenylene, which was
synthesized in early 2009.
The thinnest carbon nanotube is armchair (2,2) CNT with a diameter of 3 Å. This nanotube
was grown inside a multi-walled carbon nanotube. Assigning of carbon nanotube type was
done by combination of high-resolution transmission electron microscopy (HRTEM), Raman
spectroscopy and density functional theory (DFT) calculations.
The thinnest freestanding single-walled carbon nanotube is about 4.3 Å in diameter.
Researchers suggested that it can be either (5,1) or (4,2) SWCNT, but exact type of carbon
nanotube remains questionable. (3,3), (4,3) and (5,1) carbon nanotubes (all about 4 Å in
diameter) were unambiguously identified using more precise aberration-corrected highresolution transmission electron microscopy. However, they were found inside of doublewalled carbon nanotubes.
7. PROPERTIES OF CARBON NANOTUBES
1. Strength :# Carbon nanotubes are the strongest, flexible and stiffest materials yet discovered in terms of
tensile strength and elastic modulus respectively.
# This strength results from the covalent sp2 bonds formed between the individual carbon atoms
(which is stronger than the sp3 bonds found in Diamond & Alkenes).
# CNTs are not nearly as strong under compression. Because of their hollow structure and high
aspect ratio, they tend to undergo buckling when placed under compressive, torsional or bending
stress.
2. Hardness :# The hardness (152 Gpa) and bulk modulus (462–546) of carbon nanotubes are greater than
diamond, which is considered the hardest material. (: that of diamond is 150GPa & 420GPa).
3. Kinetic Property:# Multi-walled nanotubes, multiple concentric nanotubes precisely nested within one another;
exhibit a striking telescoping property whereby an inner nanotube core may slide, almost without
friction, within its outer nanotube shell thus creating an atomically perfect linear or rotational
bearing, the precise positioning of atoms to create useful machines.
4. Electrical Properties:# Because of the symmetry and unique electronic structure of graphene, the structure of a
nanotube strongly affects its electrical properties.-Very high current carrying capacity.
13. 5. Thermal Conductivity :# All nanotubes are expected to be very good thermal conductors along the tube.( Measurements
show that a SWNT has a room-temperature thermal conductivity more than copper.)
6. EM Wave absorption :# Current military push for radar absorbing materials (RAM) to better the stealth characteristics
of aircraft and other military vehicles. (There has been some research on filling MWNTs with
metals, such as Fe, Ni, Co, etc., to increase the absorption effectiveness of MWNTs in the
microwave regime).
7. Thermal properties:# All nanotubes are expected to be very good thermal conductors along the tube, but good
insulators laterally to the tube axis. (Measurements show that a SWNT has a room-temperature
thermal conductivity along its axis of about 3500 W·m−1·K−1;] compare this to copper, a metal
well known for its good thermal conductivity, which transmits 385 W·m−1·K−1.).
COMPARISON OF MECHANICAL PROPERTIES
Fiber material
Specific Density
Young's modulus(Tpa)
Strength (Gpa)
Strain at break(%)
Carbon
Nanotube
HS Steel
1.3 – 2
1
10 – 60
10
7.8
0.2
4.1
<10
Carbon
fiberPAN
Carbon
fiberPitch
E/s-Glass
1.7 – 2
0.2 – 0.6
1.7 – 5
0.3 – 2.4
2 – 2.2
0.4 – 0.96
2.2 – 3.3
0.27 – 0.6
2.5
0.07 – 0.08
2.4 – 4.5
4.8
Kevlar-49
1.4
0.13
3.6 – 4.1
2.8
PROPERTIES OF CONDUCTIVE MATERIALS
Material
Thermal conductivity
Electrical conductivity
> 3000
10^6 – 10^7
Copper
400
6 x 10^7
Carbon fiber-Pitch
1000
2 - 8.5 x 10^6
Carbon fiber-PAN
8 - 105
6.5 - 14 x 10^6
Carbon Nanotube
14. DEFECTS :1. Toxicity:# Under some conditions, nanotubes can cross membrane barriers, which suggests that if
raw materials reach the organs they can induce harmful effects such as inflammatory and
fibrotic reactions.
2. Crystallographic defect:# As with any material, the existence of a crystallographic defect affects the material
properties. Defects can occur in the form of atomic vacancies.
8. ADVANTAGES
1. Extremely small and lightweight.
2. Resources required to produce them are plentiful, and many can be made with only a small
amount of material.
3. Are resistant to temperature changes, meaning they function almost just as well in extreme
cold as they do in extreme heat.
4. Improves conductive, mechanical, and flame barrier properties of plastics and composites.
5. Enables clean, bulk micromachining and assembly of components.
6. Improves conductive, mechanical, and flame barrier properties of plastics and composites.
9. DISADVANTAGES
1. Despite all the research, scientists still don't understand exactly how they work.
2. Extremely small, so are difficult to work with.
3. Currently, the process is relatively expensive to produce the nanotubes.
4. Would be expensive to implement this new technology in and replace the older technology in
all the places that we could.
5. At the rate our technology has been becoming obsolete, it may be a gamble to bet on this
technology.
15. 10. APPLICATIONS
Micro-electronics / semiconductors
Conducting Composites
Artificial muscles
Super capacitors
Batteries
Field emission flat panel displays
Field Effect transistors and Single electron transistors
Nano electronics
Nano balance
Data storage
Magnetic nanotube
Nano gear
Space Elevator
Nanotube actuator
Molecular Quantum wires
Hydrogen Storage
Noble radioactive gas storage
Solar storage
Electromagnetic shielding
Thermal protection
Nanotube reinforced composites
Reinforcement of armor and other materials
Reinforcement of polymer
Fly wheels
16. 11. CHALLENGES
The greatness of a single-walled nanotube is that it is a macro-molecule and a crystal at the
same time. The dimensions correspond to extensions of fullerene molecules and the structure
can be reduced to a unit-cell picture, as in the case of perfect crystals. A new predictable (in
terms of atomic structure–property relations) carbon fiber was born. The last decade of
research has shown that indeed the physical properties of nanotubes are remarkable, as
elaborated in the various chapters of this book. A carbon nanotube is an extremely versatile
material: it is one of the strongest materials, yet highly elastic, highly conducting, small in
size, but stable, and quite robust in most chemically harsh environments. It is hard to think of
another material that can compete with nanotubes in versatility.
There are also general challenges that face the development of nanotubes into functional
devices and structures. First of all, the growth mechanism of nanotubes, similar to that of
fullerenes, has remained a mystery .With this handicap; it is not really possible yet to grow
these structures in a controlled way. Especially for electronic applications, which rely on the
electronic structure of nanotubes, this inability to select the size and helicity of nanotubes
during growth remains a drawback. More so, many predictions of device applicability are
based on joining Nano-tubes via the incorporation of topological defects in their lattices.
There is no controllable way, as of yet, of making connections between nanotubes. Some
recent reports, however, suggest the possibility of constructing these interconnected
Structures by electron irradiation and by template mediated growth and manipulation.
For bulk applications, such as fillers in composites, where the atomic structure (helicity) has a
much smaller impact on the resulting properties, the quantities of nanotubes that can be
manufactured still falls far short of what industry would need. There are no available
techniques that can produce nanotubes of reasonable purity and quality in kilogram
quantities. The industry would need tonnage quantities of nanotubes for such applications.
Another challenge is in the manipulation of nanotubes. Nano-technology is in its infancy and
the revolution that is unfolding in this .eld relies strongly on the ability to manipulate
structures at the atomic scale. This will remain a major challenge in this field, among several
others.
17. 12.CONCLUSION
Nanotubes appear destined to open up a host of new practical applications and help improve our
understanding of basic physics at the nonmetric scale.
Nanotechnology is predicted to spark a series of industrial revolutions in the next two decades
that will transform our lives to a far greater extent than silicon microelectronics did in the 20 th
century. Carbon nanotubes could play a pivotal role in this upcoming revolution if their
remarkable structural, electrical and mechanical properties can be exploited.
The remarkable properties of carbon nanotubes may allow them to play a crucial role in the
relentless drive towards miniaturization scale.
Lack of commercially feasible synthesis and purification methods is the main reason that carbon
nanotubes are still not widely used nowadays. At the moment, nanotubes are too expensive and
cannot be produced selectively. Some of the already known and upcoming techniques look
promising for economically feasible production of purified carbon nanotubes.
Some future applications of carbon nanotubes look very promising. All we need are better
production technique for large amounts of purified nanotubes that have to be found in the near
future. Nanotube promises to open up a way to new applications that might be cheaper, lower in
weight and have a better efficiency.