nano structured materials.ppt
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Nano Structured materials
What are nano structured materials?1 Nanometer = 10-9 meters. Materials with dimensions and tolerances in the range of 100 nm to 0.1 nm Metals, ceramics, polymeric materials, or composite materials One nanometer spans 3-5 atoms lined up in a row Human hair is five orders of magnitude larger than nano materials
History of Nanomaterials
1974 The word Nanotechnology first coined by Nario Taniguchi, Univ. of Tokyo --- production technology to get ultra fine accuracy and precision 1nm 1981 IBM invented STM scanning tunneling microscope which can move single atoms around 1985 new form of carbon discovered --- C60 buckminister fullerene 60 carbon atoms arranged in a sphere made of 12 pentagons and 20 hexagons
History of NanomaterialsLycurgus chalice 4th Century A.D. Appears green in reflected light and red if light is directed through it (70 nm particles of silver and gold in the glass)Lycurgus cup with diffused light Lycurgus cup with focused light
Some possible applications of Nano-materials
Nanomaterial CompositionComprised of many different elements such as carbons and metals Combinations of elements can make up nanomaterial grains such as titanium carbide and zinc sulfide Allows construction of new materials such as C60 (Bucky Balls or fullerenes) and nanotubes
NATURE - Gecko Power
Gecko foot hairs typically have diameters of 200 500 nm. Weak chemical interaction between each hair and surface (each foot has over 1 million of these hairs) provides a force of10 N/cm2. This allows Geckos to walk upside down across glass ceilings.
Nanoparticles in Smoke from Fires
Bucky Balls (C60) were discovered in soot!
FerrofluidsCoated Iron oxide nanoparticles
How they are madeClay/polymer nanocomposites can be made by subjecting clay to ion exchange and then mixing it with polymer melts Fullerenes can be made by vaporizing carbon within a gas medium
Bucky Ball (C60)
C240 colliding with C60 at 300 eV (Kinetic energy)http://www.pa.msu.edu/cmp/csc/simindex.html
Origin of the Bucky ball Discovered
in 1985 by Curl, Kroto, and Smalley, for which they received the Nobel Prize in 1996. Fullerenes /Buckminsterfullerenes, are named after Buckminster Fuller the architect and designer of the geodesic dome.
Bucky Ball properties
Arranged in pentagons and hexagons Highest tensile strength of any known 2D structure or element, including cross-section of diamonds which have the highest tensile strength of all known 3D structures (which is also a formation of carbon atoms) Also has the highest packing density of all known structures (including diamonds) Impenetrable to all elements under normal circumstances, even a helium atom with an energy of 5eV (electron Volt)
Due to their extremely resilient and sturdy nature bucky balls are debated for use in combat armor Bucky balls have been shown to be impervious to lasers, allowing for defenses from future warfare Bucky balls have also been shown to be useful at fighting the HIV virus that leads to AIDS Researchers Kenyan and Wudl found that water soluble derivates of C60 inhibit the HIV-1 protease, the enzyme responsible for the development of the virus Elements can be bonded with the bucky ball to create more diverse materials including superconductors and insulators Can be used to fashion nanotubes
Superior stiffness and strength to all other materials Extraordinary electric properties Reported to be thermally stable in a vacuum up to 2800 degrees Centigrade Capacity to carry an electric current 1000 times better than copper wires Twice the thermal conductivity of diamonds Pressing or stretching nanotubes can change their electrical properties by changing the quantum states of the electrons in the carbon bonds They are either conducting or semi-conducting depending on the their structure
Nanotube usesCan be used for containers to hold various materials on the nano-scale level Due to their exceptional electrical properties, nanotubes have a potential for use in everyday electronics such as televisions and computers to more complex uses like aerospace materials and circuits
Carbon Based Nanotubes
Applications of Nanotechnology
Next-generation computer chips Ultra-high purity materials, enhanced thermal conductivity and longer lasting nanocrystalline materials Kinetic Energy penetrators Nanocrystalline tungsten heavy alloy to replace radioactive depleted uranium Better insulation materials Create foam-like structures called aerogels from nanocrystalline materials Porous and extremely lightweight, can hold up to 100 times their weight
Improved HDTV and LCD monitors Nanocrystalline selenide, zinc sulfide, cadmium sulfide, and lead telluride to replace current phosphors Cheaper and more durable Harder and more durable cutting materials Tungsten carbide, tantalum carbide, and titanium carbide Much more wear-resistant and corrosion-resistant than conventional materials Reduces time needed to manufacture parts, cheaper manufacturing
Still more applications
Greater fuel efficiency for cars Improved spark plug materials, railplug Stronger bio-based plastics Bio-based plastics made from plant oils lack sufficient structural strength to be useful Merge nanomaterials such as clays, fibers and tubes with bio-based plastics to enhance strength and durability Allows for stronger, more environment friendly materials to construct cars, space shuttles and a myriad of other products
They are composites that consist of nanosized particles embedded in some type of matrix This is a group of promising new materials. One type of nanocomposite is currently being used in high performance tennis balls. These balls retain their original pressure and bounce twice as long as conventional ones. Air permeation through the walls of the ball is inhibited by a factor of two due to the presence of a flexible and very thin (10 to 50 ) nanocomposite barrier coating that covers the inner core.
Nano composite in high performance Tennis Balls
Because of their outstanding characteristics, these Double Core balls have recently been selected as the official balls for some of the major tennis tournaments. This nanocomposite coating consists of a matrix of butyl rubber, within which is embedded thin platelets of vermiculite,5 a natural clay mineral. The vermiculite platelets exist as single-molecule thin sheetson the order of a nanometer thick Within the butyl rubber, the vermiculite platelets are aligned such that all their lateral axes lie in the same plane; and throughout this barrier coating there are multiple layers of these platelets
Dendrimers are nanostructures that can be precisely designed and manufactured for a wide variety of applications. Dendrimers are the first large, man-made molecules with precise, nano-sized composition and well-defined threedimensional shapes. Current polymer molecules are long, spaghetti-like strands that grow in only two directions. Dendrimer molecules grow three-dimensionally by the addition of shells of branched molecules to a central core. The cores are also spacious and have sticky points on the outside to which various chemical units can be attached. By adjusting chemical properties of the core, the shells, and especially the surface layer, dendrimers can be tailored to fit the needs of specific applications.
Characteristics of Dendrimers
Dendrimer-based technologies provide exciting new interfaces between chemistry, biology and advanced materials. Efficient membrane transport Dendrimers have demonstrated rapid transport capabilities across biological membranes. High loading capacity Dendrimer structures can be used to carry and store a wide range of metals, organic or inorganic molecules by encapsulation and absorption. High uniformity and purity The synthetic process used produces dendrimers with uniform sizes, precisely defined surface functionality, and very low impurity levels. Low toxicity Most dendrimer systems display very low cytotoxicity levels. Low immunogenicity Dendrimers commonly manifest a very low or negligible immunogenic response when injected or used topically.
Applications of Dendrimers
Applications of dendrimers are underway in materials engineering, industrial, pharmaceutical, and biomedical applications. Specifically, nanoscale catalysts, novel lithographic materials, rheology modifiers, targeted drug delivery systems, MRI contrast agents, and bioadhesives represent some of the potential applications
Nanostructured films, dispersions, high surface area materials, and supramolecular assemblies are the high utility intermediates to many products with improved properties such as solar cells and batteries, sensors, catalysts, coatings, and drug delivery systems.