Syllabus: Introduction to Nano size and NanomaterialsApplications of Nanomaterials in Medicine and Catalysis…….. Carbon Nanotubes……… Basic ideas of Synthesis of Carbon Nanotubes Important Properties of Nanotubes Applications of Carbon Nanotubes………
Introduction to Nano size and Nanomaterials……Nanochemistry concerned with the uniqueproperties associated with assemblies of atomsor molecules on a scale between that of theindividual building blocks and bulk materials.It is the science of tools, technologies andmethodologies for chemical synthesis, analysis,analysis and biochemical diagnostics,performed in nanolitre to femtolitre domains.
Nanochemistry is the synthesis, analysis andcharacterization of chemical compounds at thenanoscale.“Nano” is used in scientific units to denote one-billionthof the base unit.Nanotechnology is the understanding and control ofmatter at dimensions of roughly 1 to 100 nm.THE SCIENCE OF INTERACTION AND BEHAVIOR AT THE NANO SCALE
Nano Chemistry is the study of materials of the size 1 to 100 nmrange.Nanotechnology is the understanding and control of matter atdimensions of roughly 1 to 100 nm, where unique phenomenaenable novel applications. 1 nm = 10-9 = I billionth of a meter Limit of eye’s ability to see = 10,000 nm Diameter of Hair = 750,000 nm DNA width = 2 nm H-atom = 0.1 nm Bucky ball = 1 nm Carbon nanotube = 1.3 nm E. Coli bacteria = 2,000 nm
Nano MaterialsNanomaterials are materials possessing particles sizes on the order of abillionth of a meter, nanometer.At this size range, the particles will show some unique properties likequantum size effect, surface effect, and macroscopic-quantum-tunnel effect.Nano structures are the ordered system of one-dimension, two dimension orthree dimension constructed or assembled with nanometer scale unit incertain pattern, which basically include nano-spheres, nano-rods, nano-wires, nano-belts and nanotube.Nanomaterials include,Clusters of atoms, grains that are less than 100 nm in size,Fibers that are less than 100 nm in diameter,Films that are less 100 nm in thickness,Nano-holes and Composites that are a combination of these.
Applications of Nanomaterials1. Nano materials or nano crystals provide large surface area. Hence they act as better catalysts.2. Tumors can be detected and located with incredible accuracy.3. Nano shells can float through the body attaching only to cancer cells. When excited by a laser beam, they give off heat and there by destroy tumor.4. Now borns will have their DNA mapped quickly.5. Nano technology will enable the delivery of right amount of medicines to the exact spot of the body.6. Nano technology can create biocompatible joint replacements and artery stents that will last life of the patients. Hence these need not be replaced every few years.
Classification Of Nanomaterials1. Carbon Based Nanomaterials2. Nano Composites3. Metals & Alloys4. Biological Nanomaterials5. Nano-Polymers6. Nano-Glasses7. Nano-Ceramics
Carbon Based NanomaterialsThe materials in which the “Nanocomponent” is pure carbon.Example: Carbon Nanotubes (CNT) are sheets of graphite rolled up to make atube.Due to the large surface area, CNT are interesting media for electrical energystorage.The excellent electrical and mechanical properties of carbon nanotubes likeelectrical conductivity, heat transmission capacity. Heat stability, high strength orlow density make them good candidates for use as fillers and many otherapplications.Carbon nanotubes and polymers can form foams.Carbon black is currently the most widely used carbon nanomaterial, it has foundapplication in car tyres, antistatic textiles and is used for colour effects.
Nano polymersNano polymers are nano structured polymers. This occurs duringpolymerization, in which many monomer molecules link to each other. Polymerization
Biological nanomaterialsCytochrome C is a globularprotein with 104 amino acidsin one protein chain and aniron-containing heme group.
Carbon Nano tubesA carbon nanotube is a structure which seems to be formed by rolling asheet of graphite into the shapes of a cylindrical tube.Nanotubes are categorized as single-walled nanotubes (SWNT) and multi-walled nanotubes (MWNT).Single-walled nanotubes have a diameter of close to 1 nm, with a tubelength that can be many millions of times longer. The structure of a SWNTcan be conceptualized by wrapping a one-atom-thick layer of graphitecalled graphene in to a seamless cylinder.Multi-walled carbon nanotubes consist of multiple concentric nanotubecylinders. Based on the orientations of lattices, nanotubes are of threedifferent types-Armchair, Zigzag and Chiral.
1.High pressure carbon monoxide deposition C + C + C High pressureCO C +O Temperature, FeC+C Carbon NanotubeCO C + O Fe-cluster
In this method, carbon monoxide gas and small clusters of iron atoms areheated in chamber under pressure. Carbon monoxide molecules settle oniron clusters and breaks in to carbon and oxygen atoms. Iron acts ascatalyst for breaking CO. One carbon atom binds with other carbon atomto start the nanotube lattice.Oxygen atoms give carbon dioxide (CO2) with CO.
2. Chemical Vapour Deposition Iron catalyst CH4 Heat C + 2 H2 CH4 C + 2H2
In this method, a hydrocarbon like methane is led in to aheated chamber containing a subtract coated with ironcatalyst. Due to high temperature in the chamber C-H bondsbreaks and carbon atoms are formed. They bind togetherforming carbon nanotubes.
3. Plasma process In this method methane gas which is the source of carbon is passed through a plasma torch. Carbon atoms formed combine to form carbon nanotubes.
Properties of Carbon Nanotubes1. Carbon nanotubes are very strong.2. Their tensile strength is 100 times greater than that of steel of the same diameter.3. Young’s modulus is about 5 times higher than for steel.4. They have high thermal conductivity-more than 10 times that of silver.5. They conduct electricity better than metals.6. Electron travelling through a carbon nanotube behaves like wave travelling through a smooth channel. This movement of electrons within a nanotube is called “ballistic transport”.7. They are light weight, density about one fourth of steel.8. They are sticky due to Van der Waal’s force of attraction.
Applications of Carbon Nanotubes1. They are strengtheners of composite materials.2. They act as molecular size test tubes or capsules for drug delivery3. Depending on their size, they act as electrical conductors or semiconductors.4. They are used as tips for analysis of DNA and proteins by atomic force microscopy.
Nanomaterials as CatalystsPhysical, chemical and biological properties of materials differ withrespect to the individual atoms or molecules present in the material or thesize of fundamental particle.Nanomaterials based catalysts are usually heterogeneous.Because of the small size of the particles, it can give maximum surfacearea exposed to reactant, allowing more reactions to occur. Macromolecule Nano particle