Nanomaterials • preparation • properties • applications

  • 23 февр. 2011 г.
  • 4306 Слова


Jaideep John Rodriguez

Nanoscience involves research to discover new behaviours and properties of materials with dimensions at the nanoscale which ranges roughly from 1 to 100 nanometres (nm).
In short, nanoscale materials can havedifferent properties at the nanoscale, some are better at conduct¬ing electricity or heat, some are stronger, some have different magnetic properties, and some reflect light bet¬ter or change colours as their size is changed.
Nanoscale materials also have far larger surface areas than similar volumes of larger scale materials, meaning that more surface is available for interactions with other materialsaround them.
Nanoscale materials and effects are found in nature all around us. Nature's secrets for building from the nanoscale create processes and machinery that scientists hope to imitate.
It is called nanotechnology because the small building units are measured in nanometres (nm). It is defined as one billionth of a metre or a millionth of a millimetre. This is about 1/80,000th of thediameter of a human hair, or ten times the diameter of a hydrogen atom. A sheet of paper is about 100,000 nanometres thick. There are 25,400,000 nanometres in an inch.
Many important functions of living organisms take place at the nanoscale. Our bodies and those of all animals use natural nanoscale materials, such as proteins, haemoglobin and other molecules, to control our bodies’ many systems andprocesses.
Nanoscale materials are all around us, in smoke from fire, volcanic ash, sea spray, as well as products resulting from burning or combustion processes.
At the nanoscale, objects behave quite differently from those at larger scales. Gold at the bulk scale, for instance, is an excellent conductor of heat and electric¬ity, but not of light. Properly structured gold nanoparticles, however,start absorbing light and can turn that light into heat.
Other materials can become remarkably strong when built at the nanoscale. For example, nanoscale tubes of carbon are incredibly strong. They are already being used to make bicycles, baseball bats, and some car parts today.
Carbon nanotubes also conduct both heat and electricity better than any metal, so they could be used to protectairplanes from lightning strikes and to cool com¬puter circuits.
Nanotechnology is about molecular manufactur¬ing or building things atom by atom or molecule by molecule at a time.
Nanotechnology is defined as, the design, characterization, production, and application of structures, devices, and systems by controlled manipulation of size and shape at the nanometre scale (atomic, molecular, andmacromolecular scale) that produces structures, de¬vices, and systems with at least one novel/superior char¬acteristic or property.
According to Eric Drexler, one of the leaders in this field since 1976, nanomachines will be able to build almost anything we want by assembling it atom by atom, with no environmental pollution. Consumer goods will be manufactured at virtually no cost and could not wearout because atoms are indestructible and completely recyclable.
Medical machines will be able to do basic cell re¬pair, building human cells from the atoms up. Tiny nanosized microcomputers would patrol our bodies like arti¬ficial immune systems, destroying the viruses and bacteria, believe it or not reversing the aging process.
Building things atom by atom
All the products around us are made ofatoms. The properties of these products depend on how their atoms are arranged. If we rearrange the atoms in coal we can make diamond. If we arrange the atoms in sand and add a few other trace elements, we can make computer chips. If we rearrange the atoms in dirt, water, and air, we can make potatoes.
Today's manufacturing methods are very crude at the molecular level. Casting, grinding,...
tracking img