Nanotechnology is the manipulation of matter on an atomic, molecular, and supramolecular scale. The nanotechnology has its roots date back to a 1959 talk given by Richard Feynman (http:/nano.xerox.com/nanotech/feynman.html) in which he said, "The principles of Physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something in principle, that can be done; but in practice it has not been done because we are too big". Nanotechnology may be able to create many new materials and devices with a vast range of applications, such as in medicine, electronics, biomaterials and energy production. Nanotechnology today is growing very rapidly and has infinite applications in almost everything we do -- the medicine we take, food we eat, chemicals we use, car we drive and much much more. For example, the invention of the scanning tunnelling microscope in 1981 provided unprecedented visualization of individual atoms and bonds, and was successfully used to manipulate individual atoms in 1989. The microscope's developers Gerd Binnig and Heinrich Rohrer at IBM Zurich Research Laboratory received a Nobel Prize in Physics in 1986. Binnig, Quate and Gerber also invented the analogous atomic force microscope that year.
Nanotechnology is the engineering of functional systems at the molecular scale. This covers both current work and concepts that are more advanced. In its original sense, nanotechnology refers to the projected ability to construct items from the bottom up, using techniques and tools being developed today to make complete, high performance products.
One nanometre (nm) is one billionth, or 10-9, of a metre. By comparison, typical carbon-carbon bond lengths, or the spacing between these atoms in a molecule, are in the range 0.12-0.15 nm, and a DNA double-helix has a diameter around 2 nm. On the other hand, the smallest cellular life-forms, the bacteria of the genus Mycoplasma, are around 200 nm in length. By convention, nanotechnology is taken as the scale range 1 to 100 nm following the definition used by the National Nanotechnology Initiative in the US. The lower limit is set by the size of atoms (hydrogen has the smallest atoms, which are approximately a quarter of an nm diameter) since nanotechnology must build its devices from atoms and molecules. The upper limit is more or less arbitrary but is around the size that phenomena not observed in larger structures start to become apparent and can be made use of in the nano device. These new phenomena make nanotechnology distinct from devices which are merely miniaturised versions of an equivalent macroscopic device; such devices are on a larger scale and come under the description of microtechnology.
To put that scale in another context, the comparative size of a nanometre to a metre is the same as that of a marble to the size of the earth. Or another way of putting it: a nanometre is the amount an average man's beard grows in the time it takes him to raise the razor to his face.
Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are built from molecular components which assemble themselves chemically by principles of molecular recognition. In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control.
Areas of physics such as nanoelectronics, nanomechanics, nanophotonics and nanoionics have evolved during the last few decades to provide a basic scientific foundation of nanotechnology.
Several phenomena become pronounced as the size of the system decreases. These include statistical mechanical effects, as well as quantum mechanical effects, for example the "quantum size effect" where the electronic properties of solids are altered with great reductions in particle size. This effect does not come into play by going from macro to micro dimensions. However, quantum effects can become significant when the nanometre size range is reached, typically at distances of 100 nanometres or less, the so-called quantum realm. Additionally, a number of physical (mechanical, electrical, optical, etc.) properties change when compared to macroscopic systems. One example is the increase in surface area to volume ratio altering mechanical, thermal and catalytic properties of materials. Diffusion and reactions at nanoscale, nanostructures materials and nanodevices with fast ion transport are generally referred to nanoionics. Mechanical properties of nanosystems are of interest in the nanomechanics research. The catalytic activity of nanomaterials also opens potential risks in their interaction with biomaterials.
Meanwhile, commercialization of products based on advancements in nanoscale technologies began emerging. These products are limited to bulk applications of nanomaterials and do not involve atomic control of matter. Some examples include the Silver Nano platform for using silver nanoparticles as an antibacterial agent, nanoparticle-based transparent sunscreens, and carbon nanotubes for stain-resistant textiles.
MKnano offers large variety of nano products in various forms as mentioned below.
Material Formats:
Atomic & Molecular Clusters, Buckyballs & Fullerenes, Bulk Nanostructured Metals, Magnetic Nanoparticles / Magnetic Nanostructures, Nanobelts, Nanolubricant Powders, Nanocrystals & Nanopowders, NanoFillers / NanoAdditives, Nanoparticles / Nanopowders, Nanoparticle Dispersions, Nanorods, Nanosponge Abrasives, Nano Tubes, Nanowires, Quantum Dots / Nano Dots, Reactive Electro Exploded Nano Powders.
Carbon Nanotubes:
Single wall (SWNT), Double wall (DWNT), Multiwall (MWNT), (alligned/tangled/dispersable), OH, COOH Functionalized SWNT/MWNT, Industrial Grade SWCNTs, MWCNTs, Conducting (Metallic) and Semiconducting SWCNTs, MWCNT Nonwoven Papers, CNT Foam, Special application CNTs. Other Nanotubes (Metals, Compounds, and Oxides/Hyroxides)
Quantum Dots:
Cadmium Mercury Telluride (CdHgTe), Cadmium Selenide (CdSe), Cadmium Selenide/Zinc Sulfide (CdSe/ZnS), Cadmium Sulfide (CdS), Cadmium Telluride (CdTe), Cadmium Telluride/Cadmium Sulfide (CdTe/CdS), Lead Selenide (PbSe), Lead Sulfide (PbS)
Nano Dry Lubricant Powders:
Tungsten Disulfide (WS2), Molybdenum Disulfide (MoS2), Hex-Boron Nitride (hBN), Graphite
Specially formulated Nano Lubricant Additive Powders to improve lubricity and save energy.
Materials reduced to the nanoscale can show different properties compared to what they exhibit on a macroscale, enabling unique applications. For instance, opaque substances can become transparent (copper); stable materials can turn combustible (aluminum); insoluble materials may become soluble (gold). A material such as gold, which is chemically inert at normal scales, can serve as a potent chemical catalyst at nanoscales. Much of the fascination with nanotechnology stems from these quantum and surface phenomena that matter exhibits at the nanoscale.
Dr Md Sultan Mahmud is Professor of Physics & Head, Department of Basic Sciences & Humanities, University of Asia Pacific.
E-mail: [email protected]
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