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nano 2013.pptx shsisnsgauakanahayaiakabaha
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- 2. Carbon • Carbon isa basic element of life • Carbon is special because of its ability to bond to many elements in many different ways • It is the sixth most abundant element in the universe • The most known types of carbon materials: •diamond; graphite; fullerenes; and carbon nanotubes
- 3. Solid Form ofCarbons
- 4. SIZE A meter isabout the distance from the tip of your nose to the end of your hand (1 meter = 3.28 feet). Millimeter- One thousandth of meter.(10-3 m) Micron: a micron is a millionth of a meter (or) one thousandth of millimeter (10-6 m) Nanometer: A nanometer is one thousandth of a micron (10–9 m) (or) a billionth of a meter. ie.,one billion nanometers in a meter.
- 5. How small isa nanometer?
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- 8. • Composites madefrom particles of nano-size ceramics or metals smaller than 100 nanometers can suddenly become much stronger than predicted by existing materials-science models. • For example, metals with a so-called grain size of around 10 nanometers are as much as seven times harder and tougher than their ordinary counterparts with grain sizes in the micro meter range. • The Nano particles affects many properties such as Melting point Boiling point Band gap Optical properties Electrical properties Magnetic properties • .Even the structure of materials changes with respect to Size
- 9. The properties ofmaterials can be different at the Nanoscale for two main reasons: First, Nanomaterials have a relatively larger surface area when compared to the same mass of material produced in a larger form. Nano particles can make materials more chemically reactive and affect their strength or electrical properties. Nanoscale materials are divided into three category, 1. Zero dimension – length , breadth and heights are confined at single point. (for example, Nano dots) 2. One dimension – It has only one parameter either length (or) breadth (or) height ( example:very thin surface coatings) 3. Two dimensions- it has only length and breadth (for example, nanowires and nanotubes) 4. Three dimensions -it has all parameter of length, breadth and height. (for example, Nano Particles). Second, quantum effects can begin to dominate the behaviour of matter at the Nanoscale
- 10. What do youmean by Nano Particles ? Nano Particles are the particles of size between 1 nm to 100 nm Nanometer - One billionth (10-9 ) of a meter • The size of Hydrogen atom 0.04 nm • The size of Proteins ~ 1-20 nm • Feature size of computer chips 180 nm • Diameter of human hair ~ 10 µm At the nanoscale, the physical, chemical, and biological properties of materials differ in fundamental and valuable ways from the properties of individual atoms and molecules or bulk matter • 1 nm is only three to five atoms wide. • ~40,000 times smaller than the width of an average human hair
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- 12. Noparticles are ofinterest because of the new properties (such as chemical reactivity and optical behaviour) that they exhibit compared with larger particles of the same materials. For example, titanium dioxide and zinc oxide become transparent at the nanoscale and have found application in sunscreens. Nanoparticles have a range of potential applications: In the short-term application such as in cosmetics, textiles and paints. In the longer term applications such as drug delivery where they could be to used deliver drugs to a specific site in the body. Nanoparticles can also be arranged into layers on surfaces, providing a large surface area and hence enhanced activity, relevant to a range of potential applications such as catalysts. Why Nano Particles ?
- 13. • Examples - CarbonNanotubes - Proteins, DNA - Single electron transistors AFM Image of DNA Carbon Nanotubes
- 14. Nanotechnology deals withthe creation of USEFUL materials, devices and systems using the particles of nanometer length scale and exploitation of NOVEL properties (physical, chemical, biological) at that length scale
- 15. Various Nanomaterials and Nanotechnologies •Nanoparticles • Nanocapsules • Nanofibers • Nanowires • Fullerenes (carbon 60) • Nanotubes • Nanosprings • Nanobelts • Quantum dots • Based on the size and shape, the Nano materials are classified as follows
- 16. * 16 Progressive generationof nanostructures rectang ular curvili near Nanomaterials: Nanomaterials or nanophase materials are the materials which are made of grains that are about 100nm in diameter and contain less than few ten thousands of atoms Well : - e-s move only in 2D Wire : - only in 1 D Dots: - confined in all directions, 3D. No movement quanta means "how much"
- 17. Quantum well • Itis a two dimensional system • The electron can move in two directions and restricted in one direction. Quantum Wire • It is a one-dimensional system • The electron can move in one direction and restricted in two directions. Quantum dot • It is a zero dimensional system • The electron movement was restricted in entire three dimensions
- 18. Why called Quantum? • Because, the electronic property is quantized • The spatial distance is very very small
- 19. Quantum wire Quantum wiresare ultra fine wires or linear arrays of Nano dots, formed by self-assembly They can be made from a wide range of materials such as Semiconductor Nanowires made of silicon, gallium nitride and indium phosphide. Nanowires have potential applications in 1. In high-density data storage, either as magnetic read heads or as patterned storage media 2. In electronic and opto-electronic Nanodevices, for metallic interconnects of quantum devices and Nanodevices. Nanowires can be prepared by growth techniques such as 3. Chemical Vapour deposition (CVD) 4. Electroplating
- 20. We need twodimension to calculate area of conducting material, but not present in quantum wire In quantum wire, Two dimensions are reduced and one dimension remains large Therefore, the electrical resistivity of quantum wire can be calculated using conventional formula as follows, Quantum wire cont…
- 21. General properties ofNanowire ⮚ Diameter – 10s of nanometers ⮚ Single crystal formation -- common crystallographic orientation along the nanowire axis ⮚ Minimal defects within wire ⮚ Minimal irregularities within nanowire arrays Some example of Nanowire
- 22. Magnetic nanowires ⮚ Example:Cobalt, gold, copper and cobalt-copper nanowire arrays ⮚ Important for storage device applications ⮚ Electrochemical deposition is the fabrication technique ⮚ <20 nm diameter nanowire arrays can be fabricated by electrochemical deposition Cobalt nanowires on Si substrate (UMass Amherst, 2000)
- 23. In quantum dotall the three dimensions are reduced to zero Quantum dot
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- 26. Nanorods Nanostructures shaped like longsticks with a Diameter of length range from 1-100 nm. Applications: 1. It is used in display technologies, because the reflectivity of the rods can be changed by changing their orientation with an applied electric field. 2. It is used for microelectro mechanical systems (MEMS). 3. Nanorods absorb in the near IR, and generate heat which is use for cancer therapeutics. Nanorods selectively takenup by tumor cells are locally heated, destroying only the cancerous tissue while leaving healthy cells intact.
- 27. Nanoclusters Applications: 1.In the manu-facturingof complex nanometer sized structures (example: quantum dots, magnetic domain Structures, etc.). 2. With larger clusters one can alternatively grow nano crystalline films and with small clusters, thin films are grown. 3. Irradiation with high energy cluster ions is used in the manufacturing of high standard thin films, for shallow implantation of cluster material and surface cleaning. 4. The high energy density associated with cluster ion impacts are ideal for smoothing surfaces. 5. The nanoclusters may be useful for electronic devices, for data storage, or for fostering chemical reactions.
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- 29. (a) an armchair(b)a ziz-zag nanotube. Structure of CNT
- 31. Micrographs showing controlover the nanotube diameter: (a) 40–50 nm and (b) 200–300 nm aligned carbon nanotubes
- 32. Micrographs showing thestraightness of MWCNTs grown via PECVD
- 33. nanowire Applications: • There areused in electronic, opto-electronic and nanolectro mechanical devices. • They are used as additives in advanced composites. • They are used for metallic interconnects in nanoscale quantum devices, as field-emitters • They are used as leads for biomolecular nanosensors. • They are used, to link tiny components into extremely small circuits. A nanowire has a diameter of the order of a nanometer. Nanowires exhibit aspect ratios (length - to - width ratio) of 1000 or more. As such they are often referred to as one-dimensional (1-D) materials.
- 34. Properties of NanoMaterials
- 36. The melting pointdecreases dramatically as the particle size gets below 5 nm Source: Nanoscale Materials in Chemistry, Wiley, 2001 Melting Point
- 37. * 37 Physical/chemical propertiescan change as we approach the nano-scale Melting point of gold particles M. Bawendi, MIT: web.mit.edu/chemistry/nanocluster Evident, Inc.: www.evidenttech.com K. J. Klabunde, 2001 Fluorescence of semiconductor nanocrystals By controlling nano-scale (1) composition, (2) size, and (3) shape, we can create new materials with new properties New technologies 🡪 Decreasing crystal size
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- 39. Band gap The bandgap is increases with reducing the size of the particles
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- 41. Surface Area The totalsurface area (or) the number of surface atom increases with reducing size of the particles
- 42. * 42 (ii) Magneticproperties • Nano particles of magnetic and even non magnetic solids exhibit a totally new class of magnetic properties. • Table gives an account of magnetic behavior of very small particles of various metals. • Ferro magnetic and anti ferromagnetic multilayers have been found to exhibit Giant Magneto Resistance (GMR). • Small particles differ from the bulk in that these atoms will have lower co-ordination number. • From the Fig, it is inferred that the small particles are more magnetic than the bulk material Metal Bulk Cluster Na, K Paramagnetic Ferromagnetic Fe, Co, Ni Ferro magnetic Super paramagnetic Gd, Tb Ferromagnetic Super paramagnetic Rh Paramagnetic Ferromagnetic Change in bulk magnetic moment versus co- ordination number
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- 45. Precipitation The precipitation ofsolids from a solution with metal ions is one of the most common processes for the production of nanomaterials. In supersaturated solutions, particles are formed via homogeneous or heterogeneous nucleation. The concentration and temperature of solution have a big influence on the growth rate. An inorganic metal salt, such as chloride, nitride and so on, is dissolved in water. Metal cations exist in the form of metal hydrate species, for example: Al(H2O)3+ or Fe(H2O)3+ These hydrates are added with basic solutions, such as NaOH or NH4OH. The hydrolysed species condense with each other to form either a metal hydroxide precipitate on increasing the concentration of OH− ions in the solution. The hydrolyzed species condense and then washed, filtered, dried and calcined in order to obtain the final product.
- 46. Advantages: 1. It isrelatively economical. 2. It is used to synthesize a wide range of single and multi- components oxide nanopowders. 3. Nano composites of metal oxides are produced by co-precipitation of corresponding metal hydroxides. Disadvantages: • It is difficult to control the size of particles and their subsequent aggregation.
- 47. Hydrothermal synthesis involvesthe chemical reaction of materials in aqueous solution heated (usually above BP) in a sealed vessel (bomb) above ambient temperature and pressure. Alkaline solution is used to increase solubility. Solubility in water increases with temperature, but alkaline solubility increases dramatically with temperature. Ba(OH)2 + TiO2 (300−450◦C) → BaTiO3 nanoparticles Solvothermal synthesis It is similar to the hydrothermal method. The only difference being that the precursor solution is usually not aqueous. These characteristics can be altered by changing certain experimental parameters, including reaction temperature, reaction time, solvent type, surfactant type, and precursor type. EX: titanium dioxide, graphene, carbon etc
- 49. Schematic diagram ofsolvothermal synthesis setup: (1) stainless steel autoclave (2) precursor solution (3) Teflon liner (4) stainless steel lid (5) spring
- 50. Advantages of hydrothermal/ solvothermal synthesis: 1. Easy, relatively cheap and best method of synthesis. 2. Most material can be made soluble in proper solvent by heating and pressuring the system close to its critical point. 3. The materials which may not be obtained via solid-state reaction may be prepared through hydrothermal /solvothermal synthesis; 4. Products of intermediate state, metastable state and specific phase may be easily produced. 5. Easy and precise control of the size, shape distribution, crystallinity of the final product through adjusting the parameters such as reaction temperature, reaction time, solvent type, surfactant type and precursor type. 6. Hydrothermal synthesis is used for oxide nanoparticle synthesis as the solubility is high in the alkaline medium.
- 51. Disadvantages of hydrothermal/ solvothermal synthesis: 1. The need of expensive autoclaves; 2. Safety issues during the reaction process. 3. Impossibility of observing the reaction. 4. Not for all materials synthesis. 5. May obtain variation in size. process. Applications • In the preparation of nanomaterials like zeolites, metal oxides, carbonaceous material, nanowires etc.
- 52. Thermolysis: Nanoparticles can bemade by decomposing solids or liquids at high temperatures having metal cations, or molecular anions or metal organic compounds. This is called thermolysis. It is characterized by subjecting the metal precursors (usually organometallic compounds in oxidation state zero) at high temperatures together with a stabilizing compound. Nano particles size increases with temperature rise. This is due to the elimination of stabilizing molecules, generating a greater aggregation of the particles. For example Li particles can be made by decomposing lithium azide, LiN3.
- 55. Electrodeposition It is theprocess by which an applied current or potential is used to deposit a film of metal or alloy by the reduction of metallic ions onto a conductive substrate. This is a self-propagating process. Some porous membrane with nano-size channels (pores) are used as templates from conduct the growing of nanowires. Pore size ranging from 10nm to 100nm can be achieved. Electrochemical deposition is a template based synthesis - Negative template ie., uses prefabricated cylindrical nanopores in a solid material as templates and Positive template ie., use wire-like nanostructures, such as DNA, protein and carbon nanotubes as templates. Nanowires are formed on the outer surface of the templates. From the templates wire-like and tube-like structures are obtained.
- 57. Electrodeposition has threemain attributes that make it so well suited for nano-, bio- and microtechnologies. 1. It can be used to grow functional material through complex 3D masks. 2. It can be performed near room temperature from waterbased electrolytes. 3. It can be scaled down to the deposition of a few atoms or up to large dimensions.
- 58. Advantages: 1. It isa rapidity and low cost method. 2. The product is of high purity, production of free-standing parts with complex shapes. 3. Higher deposition rates. 4. It produce particle sizes ranging from nm to μm. 5. Produces compositions unattainable by other techniques. Limitations • Only applicable to electrically conductive materials: metals, alloys, semiconductors, and electrical conductive polymers. Applications • In fabrication of nanorods, nanowires, and nanotubes of polymers, metals, semiconductors, and oxides.
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- 60. This is animportant method for making carbon nanotubes. Nanotubes of 10 to 20 nm in diameter and 100 μm long can be made by this method. A quartz tube filled with argon gas and a graphite target are heated at high temperature. The graphite target contains catalysts like cobalt or nickel in small amounts. An intense pulsed laser beam at higher temperature (1200◦C) is incident on the target and evaporating carbon from the graphite. The argon gas then drives the carbowater cooled n atoms from the high temperature zone to the copper collector on which they condense into nanotubes.
- 61. Advantages 1. SWNT Longbundles of tubes (5-20 microns), with individual diameter from 1-2 nm is produced. 2. SWNTs with good diameter control and few defects is produced. 3. The reaction product is pure. Disadvantages 1. The yield of this process is low. 2. It contains carbon Nanotubes along with Carbon Nanoparticles, which is not ideal for industrial applications. 3. Expensive than CVD.
- 62. Chemical Vapour DepositionMethod This is one of the popular method to synthesize Carbon nanotubes. It is produced by passing a carbon-containing gas, such as a acytelene, over a catalyst. The catalyst consists of nano-sized particles of metal, usually iron, cobalt or nickel. These particles catalyse the breakdown of the gaseous molecules into carbon, and a tube then begins to grow with a metal particle at the tip of a tube. A bunch of carbon nano particle is easily produced. The perfection of carbon nanotubes produced in this way has generally been poorer than those made by arc evaporation.
- 64. Advantages: 1. Produces highlydense and pure nanomaterials. 2. Produces uniform film with high deposition rate. 3. The crystal structure, surface morphology and orientation can be easily control with parameters. 24 Nanomaterials 4. Economically cheaper technique with high yield. Drawbacks: 1. Precursor gases are toxic, corrosive and flammable in nature leading to chemical and safety hazard. 2. Difficult to deposit multicomponent materials using multi-source precursors
- 65. Applications of NanoMaterials
- 66. • Because oftheir small size, nanoscale devices can readily interact with biomolecules on both the surface of cells and inside of cells. • By gaining access to so many areas of the body, they have the potential to detect disease and the deliver treatment. 1. Nanotechnology Applications in Medicine • Nanoparticles can can deliver drugs directly to diseased cells in your body. • Nanomedicine is the medical use of molecular- sized particles to deliver drugs, heat, light or other substances to specific cells in the human body.
- 67. • Quantum dot-that identify the location of cancer cells in the body. • Nano Particles - that deliver chemotherapy drugs directly to cancer cells to minimize damage to healthy cells. • Nanoshells - that concentrate the heat from infrared light to destroy cancer cells with minimal damage to surrounding healthy cells. • Nanotubes- used in broken bones to provide a structure for new bone material to grow.
- 68. Nano shells asCancer Therapy Nano shells are injected into cancer area and they recognize cancer cells. Then by applying near-infrared light, the heat generated by the light-absorbing Nano shells has successfully killed tumor cells while leaving neighboring cells intact.
- 71. • In thisdiagram (next page), Nano sized sensing wires are laid down across a micro fluidic channel. As particles flow through the micro fluidic channel, the Nanowire sensors pick up the molecular identifications of these particles and can immediately relay this information through a connection of electrodes to the outside world. • These Nanodevices are man-made constructs made with carbon, silicon Nanowire. • They can detect the presence of altered genes associated with cancer and may help researchers pinpoint the exact location of those changes Nanowires – used as medical sensor
- 73. Past Shared computing thousandsof people sharing a mainframe computer Present Personal computing Future Ubiquitous computing thousands of computers sharing each and everyone of us; computers embedded in walls, chairs, clothing, light switches, cars….; characterized by the connection of things in the world with computation. 2. Nano Computing Technology
- 74. 3. Sunscreens andCosmetics • Nanosized titanium dioxide and zinc oxide are currently used in some sunscreens, as they absorb and reflect ultraviolet (UV) rays. • Nanosized iron oxide is present in some lipsticks as a pigment. 4. Fuel Cells The potential use of nano-engineered membranes to intensify catalytic processes could enable higher-efficiency, small-scale fuel cells. 5. Displays • Nanocrystalline zinc selenide, zinc sulphide, cadmium sulphide and lead telluride are candidates for the next generation of light-emitting phosphors. • CNTs are being investigated for low voltage field-emission displays; their strength, sharpness, conductivity and inertness make them potentially very efficient and long-lasting emitters.
- 75. 6. Batteries • Withthe growth in portable electronic equipment (mobile phones, navigation devices, laptop computers, remote sensors), there is great demand for lightweight, high-energy density batteries. • Nanocrystalline materials are candidates for separator plates in batteries because of their foam-like (aerogel) structure, which can hold considerably more energy than conventional ones. • Nickel–metal hydride batteries made of nanocrystalline nickel and metal hydrides are envisioned to require less frequent recharging and to last longer because of their large grain boundary (surface) area. 7. Catalysts In general, nanoparticles have a high surface area, and hence provide higher catalytic activity.
- 76. 8. Magnetic NanoMaterials applications • It has been shown that magnets made of nanocrystalline yttrium– samarium–cobalt grains possess unusual magnetic properties due to their extremely large grain interface area (high coercivity can be obtained because magnetization flips cannot easily propagate past the grain boundaries). • This could lead to applications in motors, analytical instruments like magnetic resonance imaging (MRI), used widely in hospitals, and microsensors. • Nanoscale-fabricated magnetic materials also have applications in data storage. • Devices such as computer hard disks storage capacity is increased with Magnetic Nano materials
- 77. . • Unfortunately, insome cases, the biomedical metal alloys may wear out within the lifetime of the patient. But Nano materials increases the life time of the implant materials. • Nanocrystalline zirconium oxide (zirconia) is hard, wear resistant, bio-corrosion resistant and bio-compatible. • It therefore presents an attractive alternative material for implants. • Nanocrystalline silicon carbide is a candidate material for artificial heart valves primarily because of its low weight, high strength and inertness. 9. Medical Implantation 10. Water purification •Nano-engineered membranes could potentially lead to more energy- efficient water purification processes, notably in desalination process.
- 78. 11. Military Battle Suits •Enhanced nanomaterials form the basis of a state-of- the-art ‘battle suit’ that is being developed. • A short-term development is likely to be energy-absorbing materials that will withstand blast waves; • longer-term are those that incorporate sensors to detect or respond to chemical and biological weapons (for example, responsive nanopores that ‘close’ upon detection of a biological agent).
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