FET0702Why Nanoscience and Nanotechnology f

Journal of Faculty of Engineering & Technology, 2007-2008, pages, 11-20 Why Nanoscience and Nanotechnology? What is there for us? Syeda Amber Yousaf and Salamat Ali 1 Abstract Nanotechnology is about to affect almost every field of human life. It is an enabling technology that will impact electronics and computing, medicine, materials and manufacturing, catalysis, energy and transportation. It will revolutionize future world by changing the current using materials in durability and reactivity. We have great opportunities to make things smaller in size, lighter in weight and stronger. Therefore scientists and engineers have great interest in this emerging field. From the present activities going on in the world particular by no. of conferences, seminars and the money injected in this field we can say that this rapidly expanding field is going to bring about an innovative transformation in upcoming years. 1 Dept. of Physics, GC. University, Lahore.
Journal of Faculty of Engineering & Technology, 2007-2008 12 Introduction to Nanoscience Nanoscience is an emerging area of science which concerns itself with the study of materials that have very small dimensions, in the range of nano scale. The word itself is a combination of nano, from the Greek "nanos" (or Latin "nanus"), meaning "Dwarf", and the word "Science " meaning knowledge [1]. It is an interdisciplinary field that seeks to bring about mature nanotechnology, focusing on the nano scale intersection of fields such as physics, biology, engineering, chemistry, computer science and more. Nanoscience is the study of phenomena on a nanometer scale. Atoms are a few tenths of a nanometer in diameter and molecules are typically a few nanometers in size. Nanometer is a magical point on the length scale, for this is the point where the smallest man-made devices meet the atoms and molecules of the natural world. Typically nano means 10 -9 . So, a nanometer is one billionth of a meter and is the unit of length that is generally most appropriate for describing the size of single molecule. Nanometer objects are too small to be seen with naked eye. Infect, if one wanted to see a 10 nm sized marble in his hand, his eye would have to be smaller than a human hair. Anyhow the rough definition of Nanoscience could be anything which has at least one dimension less than 100 nanometer. How big a nanometer is, the idea has been elaborated in Fig.1 [2]. Classification of Nanomaterials Nanomaterials can be classified dimension wise into following categories. Classification Examples 1 dimension < 100nm nanorods, nanowires etc. 2 dimensions < 100nm Tubes, fibers, platelets, etc. Zero or 3 dimensions < 100nm Particles, quantum dots, hollow Spheres, etc. On the basis of phase composition, nanomaterials in different phases can be classified as, Single phase solids include crystalline, amorphous particles and layers, etc. Multi phase solids include matrix composites, coated particles, etc. Multi phase systems include colloids, aero gels, Ferro fluids, etc.
Journal of Faculty of Engineering & Technology, 2007-2008 13 Fig .1. A bird view of a nanometer. Nanoscience and Physics Physics is the mother of natural sciences. In principle, physics can be used to explain everything that goes on at the nano scale. There is active physics research going on in nanomechanics, quantum computation, quantum teleportation, artificial atoms etc. At nanometer scale physics is different. Properties not seen on a macroscopic scale now become important- such as quantum mechanical and thermodynamic properties. Rather than working with bulk materials, one works with individual atoms and molecules. By learning about an individual molecule‟s properties, we can put them together in very well-defined ways to produce new materials with new and amazing characteristics. Some Physical Properties of Nanomaterials Materials reduced to nano scale can suddenly show very different properties compared to what they exhibit on a macro scale, enabling unique applications. For instance: Copper which is an opaque substance become transparent. Platinum which is an inert material become catalyst. Aluminum which is a stable material turns combustible. Silicon insulators become conductors. Gold which is solid, inert and yellow on room temperature at micro scale becomes liquid and red in color at nano scale on room temperature. It also gets unusual catalytic properties not seen at macro scale. Figure2 [3] shows dependence of melting point on the particle size.
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