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IMPS College Of Engineering & Technology. 1 Presentation by: s.thiyagarajan 2nd year ece NANO TECHNOLOGY & NANO TUBES

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An engineered DNA strand Semiconducting metal junction formed by two carbon nanotubes What is Nanotechnology? “Nanotechnology is the art an science of manipulating matter at the nanoscale” 2 Buckyball

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What is Nanoscale? 1.27 × 107 m 0.22 m 0.7 × 10-9 m Fullerenes C60 12,756 Km 22 cm 0.7 nm 10 millions times smaller 1 billion times smaller 3

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2000 Years Ago – Sulfide nanocrystals used by Greeks and Romans to dye hair. 1000 Years Ago (Middle Ages) – Gold nanoparticles of different sizes used to produce different colors in stained glass windows. 1974 – “Nanotechnology” - Taniguchi uses the term nanotechnology for the first time. 1981 – IBM develops Scanning Tunneling Microscope. This microscope evolved to allow the manipulation of individual atoms and molecules in the field of Nano technology. 1985 – “Buckyball” - Scientists at Rice University and University of Sussex discover C60 1991 – Carbon nanotube discovered by S. Iijima History of Nanotechnology 4

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NEED FOR NANOTECHNOLOGY Allows the placement of small structures placed with precision,simplicity and low cost Leads to economic growth Enhances national security Improves the quality of life Leads to job creation 5

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IMPS College Of Engineering & Technolgy. Nanoscale Approaches and Fabrication 6

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With NT, we can create unique materials and products which are: Stronger Lighter Cheaper Durable Precise Computers can become a billion times faster and a million times smaller Automatic Pollution Cleanup Manufacturing at almost no cost End of Illnesses (i.e. cancer, heart disease) Universal Immunity (i.e. aids, flu) Body Sculpting (i.e. change your appearance) Industrial Medical Material Advantages 7

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Carbon NanoTubes Medicine Information Technology Nano Robots Energy Nanotechnology Applications 8 Stinger: Targeted Drug Delivery OLED Nanorobot Aerogel NANO FILTERS

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Carbon NanoTubes The joining of two carbon nanotubes Carbon Nanotubes:: This rotating picture is actually a model of carbon nanotube, the strongest and stiffest materials discovered till to date. CNTs also known as buckytubes are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1 carbon nanotube 9

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Single Walled Nanotubes (SWNT) The (n,m) nanotube naming scheme can be thought of as a vector (Ch) in an infinite graphene sheet that describes how to "roll up" the graphene sheet to make the nanotube. 10 Single-walled nanotubes have a diameter of close to 1 nanometer, with a tube length that can be many millions of times longer. The structure of a SWNT can be conceptualized by wrapping a one-atom-thick layer of graphite called graphene into a seamless cylinder. The way the graphene sheet is wrapped is represented by a pair of indices (n,m) called the chiral vector Single-walled nanotubes are an important variety of carbon nanotube because they exhibit electric properties

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There are two models of description of these MWNT:: In the Russian Doll model, sheets of graphite are arranged in concentric cylinders In the Parchment model, a single sheet of graphite is rolled in around itself, resembling a scroll of parchment or a rolled newspaper Multi Walled Nano Tubes (MWNT) Multi-walled nanotubes (MWNT) consist of multiple rolled layers (concentric tubes) of graphite 11

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Torus A nanotorus is theoretically described as carbon nanotubes bent into a torus (doughnut shape). Nanotori are predicted to have many unique properties, such as ‘magnetic moments’ which is the property of magnet that interacts with an applied field to give a mechanical moment Nanobud Carbon nanobuds are a newly created material combining two previously discovered allotropes of carbon: carbon nanotubes and fullerenes This hybrid material has useful properties of both fullerenes and carbon nanotubes. A stable nanobud structure 12

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Properties of Nano Tubes Strength :- Carbon nanotubes are the strongest and stiffest materials yet discovered in terms of tensile strength and elastic modulus respectively. Hardness:- The hardness of compressed SWNTs is 462–546 GPa, surpassing the value of 420 GPa for diamond Electrical:- In theory, metallic nanotubes can carry an electrical current density of 4 × 109 A/cm2 which is more than 1,000 times greater than metals such as copper. Thermal:- All nanotubes are expected to be very good thermal conductors along the tube, the temperature stability of carbon nanotubes is estimated to be up to 2800 °C in vacuum and about 750 °C in air. 13

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Solar cells Solar cells developed at the New Jersey Institute of Technology use a carbon nanotube complex, formed by a mixture of carbon nanotubes and carbon buckyballs Ultracapacitors With a nanotube electrode the hollow spaces that store charge may be tailored to any size and consequently the capacity should be increased considerably. Paper batteries A paper battery is a battery engineered to use a paper-thin sheet of cellulose infused with aligned carbon nanotubes. The nanotubes act as electrodes; allowing the storage devices to conduct electricity. The battery, which functions as both a lithium-ion battery and a supercapacitor, can provide a long, steady power output comparable to a conventional battery. Other applications Carbon nanotubes have been implemented in nanoelectromechanical systems, including mechanical memory elements (NRAM being developed by Nantero Inc.) Applications of Nano Tubes Aligned nanotubes are preferred for many applications. 14

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Health and safety issues Nanoparticles can cause serious illness or damage human body. Untraceable destructive weapons of mass destruction. Social & Political issues Creates social strife through increasing wealth gap Advisability of increasing scope of the technology creates political dilemma 15 Implications of Nanotechnology

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Exposure of human and the environment to nanomaterials at different stages of product life cycle “Grey-goo” It is a hypothetical situation where self replicating nanobots go out of control, and consume all matter on earth. Environmental issues Nanopollution is created by toxic wastes from nanomaterial manufacturing Enhances Global warming in the long run “The Living Fog” formed by billions of replicating nanobots gone mad 16

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Thank you….. 17

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Any Queries ???? 18