21-12-2010, 03:24 PM
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Presented By:T.PARDHU
Learning Outcomes
At the end of applications
the session you will be able to describe the processing methods for carbon nanotubes and their
Learn basic experimental methods / tools used in nanotechnology
Get some idea on future nanotech applications
Outline
Introduction
Carbon nanotubes
Advanced nanotech devices
Lithography techniques
Microscopes for nanotechnology
Nanoscience
A nanometre (nm) is one thousand millionth of a metre.
For comparison, a single human hair is about 80,000 nm wide
Definition for Nanoscience: The study of phenomena and manipulation of materials at atomic, molecular and macromolecular scales, where properties differ significantly from those at a larger scale; and nanotechnologies as the design, characterisation, production and application of structures, devices and systems by controlling shape and size at the nanometre scale.
In some sense, nanoscience and nanotechnologies are not new. Chemists have been making polymers, which are large molecules made up of nanoscale subunits, for many decades and nanotechnologies have been used to create the tiny features on computer chips for the past 20 years. However, advances in the tools that now allow atoms and molecules to be examined and probed with great precision have enabled the expansion and development of nanoscience and nanotechnologies.
People are interested in the nanoscale (which we define to be from 100nm down to the size of atoms (approximately 0.2nm)) because it is at this scale that the properties of materials can be very different from those at a larger scale.
Units
What is nanotechnology?
Materials properties can be different at nanoscale
Nanomaterials have a relatively larger surface area when compared to the same mass of material produced in a larger form. This can make materials more chemically reactive (in some cases materials that are inert in their larger form are reactive when produced in their nanoscale form), and affect their strength or electrical properties.
Quantum effects can begin to dominate the behaviour of matter at the nanoscale - particularly at the lower end - affecting the optical, electrical and magnetic behaviour of materials.
Materials can be produced that are nanoscale in one dimension (very thin surface coatings), in two dimensions (nanowires and nanotubes) or in all three dimensions (for example, nanoparticles).
Physical/Mechanical Properties
Electrical Transport
Resistivity 10-4 W-cm
Maximum Current Density 1013 A/m2
Thermal Transport
Thermal Conductivity (Room Temperature) ~ 2000 W/m•K
Phonon Mean Free Path ~ 100 nm
Relaxation Time ~ 10-11 s
Elastic Behavior
Young's Modulus (SWNT) ~ 1 TPa
Young's Modulus (MWNT) 1.28 TPa
Maximum Tensile Strength ~30 GPa
Superior strength & lightweight: Ropeway to outer space?
Expensive to produce
$54,000/1kg (year 2007)
Single-walled nanotubes (SWNTs) Purity: > 90 vol% (carbon nanotubes) > 50 vol% (single-walled nanotubes)
Diameter: 1-2 nm (from HRTEM) Diameter: 0.8-1.6 nm (from Raman spectra) Average diameter: 1.1 nm (from Raman spectra) Length: 5-15 um SSA: > 400 m2/g
Potential applications for carbon nanotubes
Additives in ploymers
Catalysts
Electron field emitters for
cathode ray lighting elements
flat panel display
gas-discharge tubes in telecom networks
Electromagnetic-wave absorption and shielding
Energy conversion
Lithium-battery anodes
Hydrogen storage
Nanotube composites (by filling or coating);
Nanoprobes for
STM, AFM, and EFM tips
nanolithography
nanoelectrodes
drug delivery
sensors
Reinforcements in composites
Supercapacitor
Applications (Materials)
Very thin coatings for electronics and active surfaces (self-cleaning windows).
In most applications the nanoscale components will be fixed or embedded but in some, such as those used in cosmetics and in some pilot environmental remediation applications, free nanoparticles are used.
The ability to machine materials to very high precision and accuracy (better than 100nm) is leading to considerable benefits in a wide range of industrial sectors, for example in the production of components for the information and communication technology (ICT), automotive and aerospace industries.
Applications (Materials)
Range of products: silicon based electronics, displays, paints, batteries, micromachined silicon sensors and catalysts.
Composites that exploit the properties of carbon nanotubes – rolls of carbon with one or more walls, measuring a few nanometres in diameter and up to a few centimetres in length – which are extremely strong and flexible and can conduct electricity.
At the moment the applications of these tubes are limited by the difficulty of producing them in a uniform manner and separating them into individual nanotubes.
Lubricants based on inorganic nanospheres.
Magnetic materials using nanocrystalline grains; nanoceramics used for more durable and better medical prosthetics; automotive components or high-temperature furnaces; and nano-engineered membranes for more energy efficient water purification.
Applications (Electronics)
Current manufacturing standard for silicon chips in terms of the length of a particular feature in a memory cell is 90nm, but it is predicted that by 2016 this will be just 22nm.
Much of the miniaturisation of computer chips to date has involved nanoscience and nanotechnologies, and this is expected to continue in the short and medium term.
Alternatives to silicon-based electronics are already being explored through nanoscience and nanotechnologies, for example plastic electronics for flexible display screens.
Other nanoscale electronic devices currently being developed are sensors to detect chemicals in the environment, to check the edibility of foodstuffs, or to monitor the state of mechanical stresses within buildings.
Much interest is also focused on quantum dots, semiconductor nanoparticles that can be ‘tuned’ to emit or absorb particular light colours for use in solar energy cells or fluorescent biological labels.
Applications (Medicine)
Disease diagnosis, drug delivery targeted at specific sites in the body and molecular imaging are being intensively investigated and some products are undergoing clinical trials.
Nanocrystalline silver, which is known to have antimicrobial properties, is being used in wound dressingsin the USA.
The production of materials and devices such as scaffolds for cell and tissue engineering, and sensors that can be used for monitoring aspects of human health.
In the longer term, the development of nanoelectronic systems that can detect and process information could lead to the development of an artificial retina or cochlea.
Progress in the area of bio-nanotechnology will build on our understanding of natural biological structures on the molecular scale, such as proteins.
Industrial applications
So far (2006), the relatively small number of applications of nanotechnologies that have made it through to industrial application represent evolutionary rather than revolutionary advances.
Current applications are mainly in the areas of determining the properties of materials, the production of chemicals, precision manufacturing and computing.
In mobile phones for instance, materials involving nanotechnologies are being developed for use in advanced batteries, electronic packaging and in displays. The total weight of these materials will constitute a very small fraction of the whole product but be responsible for most of the functions that the devices offer.
There will be significant challenges in scaling up production from the research laboratory to mass manufacturing.
In the longer term it is hoped that nanotechnologies will enable more efficient approaches to manufacturing which will produce a host of multi-functional materials in a cost-effective manner, with reduced resource use and waste.
Maybe possible to develop mechanical nano-machines which would be capable of producing materials (and themselves) atom-by-atom. Alongside such hopes for self-replicating machines, fears have been raised about the potential for these (as yet unrealised) machines to go out of control, produce unlimited copies of themselves, and consume all available material on the planet in the process.
Presented By:T.PARDHU
Carbon nano-tubes “Nanotechnology”
Learning Outcomes
At the end of applications
the session you will be able to describe the processing methods for carbon nanotubes and their
Learn basic experimental methods / tools used in nanotechnology
Get some idea on future nanotech applications
Outline
Introduction
Carbon nanotubes
Advanced nanotech devices
Lithography techniques
Microscopes for nanotechnology
Nanoscience
A nanometre (nm) is one thousand millionth of a metre.
For comparison, a single human hair is about 80,000 nm wide
Definition for Nanoscience: The study of phenomena and manipulation of materials at atomic, molecular and macromolecular scales, where properties differ significantly from those at a larger scale; and nanotechnologies as the design, characterisation, production and application of structures, devices and systems by controlling shape and size at the nanometre scale.
In some sense, nanoscience and nanotechnologies are not new. Chemists have been making polymers, which are large molecules made up of nanoscale subunits, for many decades and nanotechnologies have been used to create the tiny features on computer chips for the past 20 years. However, advances in the tools that now allow atoms and molecules to be examined and probed with great precision have enabled the expansion and development of nanoscience and nanotechnologies.
People are interested in the nanoscale (which we define to be from 100nm down to the size of atoms (approximately 0.2nm)) because it is at this scale that the properties of materials can be very different from those at a larger scale.
Units
What is nanotechnology?
Materials properties can be different at nanoscale
Nanomaterials have a relatively larger surface area when compared to the same mass of material produced in a larger form. This can make materials more chemically reactive (in some cases materials that are inert in their larger form are reactive when produced in their nanoscale form), and affect their strength or electrical properties.
Quantum effects can begin to dominate the behaviour of matter at the nanoscale - particularly at the lower end - affecting the optical, electrical and magnetic behaviour of materials.
Materials can be produced that are nanoscale in one dimension (very thin surface coatings), in two dimensions (nanowires and nanotubes) or in all three dimensions (for example, nanoparticles).
Physical/Mechanical Properties
Electrical Transport
Resistivity 10-4 W-cm
Maximum Current Density 1013 A/m2
Thermal Transport
Thermal Conductivity (Room Temperature) ~ 2000 W/m•K
Phonon Mean Free Path ~ 100 nm
Relaxation Time ~ 10-11 s
Elastic Behavior
Young's Modulus (SWNT) ~ 1 TPa
Young's Modulus (MWNT) 1.28 TPa
Maximum Tensile Strength ~30 GPa
Superior strength & lightweight: Ropeway to outer space?
Expensive to produce
$54,000/1kg (year 2007)
Single-walled nanotubes (SWNTs) Purity: > 90 vol% (carbon nanotubes) > 50 vol% (single-walled nanotubes)
Diameter: 1-2 nm (from HRTEM) Diameter: 0.8-1.6 nm (from Raman spectra) Average diameter: 1.1 nm (from Raman spectra) Length: 5-15 um SSA: > 400 m2/g
Potential applications for carbon nanotubes
Additives in ploymers
Catalysts
Electron field emitters for
cathode ray lighting elements
flat panel display
gas-discharge tubes in telecom networks
Electromagnetic-wave absorption and shielding
Energy conversion
Lithium-battery anodes
Hydrogen storage
Nanotube composites (by filling or coating);
Nanoprobes for
STM, AFM, and EFM tips
nanolithography
nanoelectrodes
drug delivery
sensors
Reinforcements in composites
Supercapacitor
Applications (Materials)
Very thin coatings for electronics and active surfaces (self-cleaning windows).
In most applications the nanoscale components will be fixed or embedded but in some, such as those used in cosmetics and in some pilot environmental remediation applications, free nanoparticles are used.
The ability to machine materials to very high precision and accuracy (better than 100nm) is leading to considerable benefits in a wide range of industrial sectors, for example in the production of components for the information and communication technology (ICT), automotive and aerospace industries.
Applications (Materials)
Range of products: silicon based electronics, displays, paints, batteries, micromachined silicon sensors and catalysts.
Composites that exploit the properties of carbon nanotubes – rolls of carbon with one or more walls, measuring a few nanometres in diameter and up to a few centimetres in length – which are extremely strong and flexible and can conduct electricity.
At the moment the applications of these tubes are limited by the difficulty of producing them in a uniform manner and separating them into individual nanotubes.
Lubricants based on inorganic nanospheres.
Magnetic materials using nanocrystalline grains; nanoceramics used for more durable and better medical prosthetics; automotive components or high-temperature furnaces; and nano-engineered membranes for more energy efficient water purification.
Applications (Electronics)
Current manufacturing standard for silicon chips in terms of the length of a particular feature in a memory cell is 90nm, but it is predicted that by 2016 this will be just 22nm.
Much of the miniaturisation of computer chips to date has involved nanoscience and nanotechnologies, and this is expected to continue in the short and medium term.
Alternatives to silicon-based electronics are already being explored through nanoscience and nanotechnologies, for example plastic electronics for flexible display screens.
Other nanoscale electronic devices currently being developed are sensors to detect chemicals in the environment, to check the edibility of foodstuffs, or to monitor the state of mechanical stresses within buildings.
Much interest is also focused on quantum dots, semiconductor nanoparticles that can be ‘tuned’ to emit or absorb particular light colours for use in solar energy cells or fluorescent biological labels.
Applications (Medicine)
Disease diagnosis, drug delivery targeted at specific sites in the body and molecular imaging are being intensively investigated and some products are undergoing clinical trials.
Nanocrystalline silver, which is known to have antimicrobial properties, is being used in wound dressingsin the USA.
The production of materials and devices such as scaffolds for cell and tissue engineering, and sensors that can be used for monitoring aspects of human health.
In the longer term, the development of nanoelectronic systems that can detect and process information could lead to the development of an artificial retina or cochlea.
Progress in the area of bio-nanotechnology will build on our understanding of natural biological structures on the molecular scale, such as proteins.
Industrial applications
So far (2006), the relatively small number of applications of nanotechnologies that have made it through to industrial application represent evolutionary rather than revolutionary advances.
Current applications are mainly in the areas of determining the properties of materials, the production of chemicals, precision manufacturing and computing.
In mobile phones for instance, materials involving nanotechnologies are being developed for use in advanced batteries, electronic packaging and in displays. The total weight of these materials will constitute a very small fraction of the whole product but be responsible for most of the functions that the devices offer.
There will be significant challenges in scaling up production from the research laboratory to mass manufacturing.
In the longer term it is hoped that nanotechnologies will enable more efficient approaches to manufacturing which will produce a host of multi-functional materials in a cost-effective manner, with reduced resource use and waste.
Maybe possible to develop mechanical nano-machines which would be capable of producing materials (and themselves) atom-by-atom. Alongside such hopes for self-replicating machines, fears have been raised about the potential for these (as yet unrealised) machines to go out of control, produce unlimited copies of themselves, and consume all available material on the planet in the process.
