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INTRODUCTION OF NANOCHEMISRY.
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Nanochemistry. The term "nanochemistry" was first used by Ozin in 1992. Nano is a prefix used to describe "one billionth” or “tiny particle’’. A nanometre (nm) is a billionth of a metre, or a millionth of a millimetre. Nanometer = 10−9m. Atoms are very small. Diameter of 1 atom can vary from 0.1 to 0.5 nm. Dimension range of 1to 100 nm is called nanoscale. One nanometer is called a magical point on dimension scale..
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Bascis of nanochemistry.
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1. nanoparticles. Size ranges from 1-100 nm. They are obtained as colloids. The colloidal particles have tendency to remain single crystal are called nanocrystals. Metal particles smaller than 1 nm are usually called atom clusters. These are tiny aggregates of atoms > crystals but < molecules. It posses electronic , magnetic and optical properties. It exhibits an electronic behavior, governed by quantum physics, They are called as quantum dots. Example: TiO2,gold,silver,ZnO,etc.,.
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2.nanomaterials. Size ranges less than 100 nm at least in one dimension. It have optical, electronic,magnetic, mechanical properties. Types of nanomaterials:.
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3.Nanochemistry (or) nanoscience. It is a study of phenomena and manipulation of materials at atomic, molecular, macro scales. The physical and chemical properties of matter change at the nano level compare to the bulk..
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4. nanotechnology. It is defined as the design,characterization,production and applications of structures and devices. It is by controlling size and shape at10−9m (or) the single-atomic level. Examples: Sunscreen. Clothing. Adhesives. Car paint. Sports equipment. Computers. Medicine..
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Distinction between nano particles, molecules and bulk material.
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S.no Properties Atom/molecule Nano particles/Nano cluster Bulk material 1. Size 10-10 m 10−9m. Micro level 2. Appearance Depends upon size and shape varies Depends upon size and shape varies Depends upon size and shape varies 3. Melting point Low Very low High 4. Surface area Very large 2x larger Very small 5. Hardness Less strength More strength Less strength 6. Corrosion Low resistivity High resistivity Low resistivity 7. Electronic structure Confined Confined Confined 8. Geometric structure Well-defined structure and predictable Well-defined structure and predictable Crystal structure decides. 9. Example NaCl, HCl (NaCl)n Gold bar & silver bar.