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What is Nanotechnology?

A basic definition: 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.

 

With 15,342 atoms, this parallel-shaft speed reducer gear
is one of the largest nanomechanical devices ever modeled in atomic detail. 

K. Eric Drexler

The Meaning of Nanotechnology

When K. Eric Drexler popularized the word ‘nanotechnology’ in the 1980’s, he was talking  about building machines on the scale of molecules, a few nanometers wide—motors, robot arms,  and even whole computers, far smaller than a cell. Drexler spent the  next ten years describing and analyzing these incredible devices, and  responding to accusations of science fiction. Meanwhile, mundane  technology was developing the ability to build simple structures on a  molecular scale. As nanotechnology became an accepted concept, the meaning of the word shifted to encompass the simpler kinds of nanometer-scale technology. The U.S. National Nanotechnology Initiative was  created to fund this kind of nanotech: their definition includes  anything smaller than 100 nanometers with novel properties.
Much of the work being done today that carries the name ‘nanotechnology’  is not nanotechnology in the original meaning of the word.  Nanotechnology, in its traditional sense, means building things from the  bottom up, with atomic precision. This theoretical capability was envisioned as early as 1959 by the renowned physicist Richard Feynman.

I want to build a billion tiny factories, models of each other, which are manufacturing simultaneously. . . 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. — Richard Feynman, Nobel Prize winner in physics

Based  on Feynman’s vision of miniature factories using nanomachines to build  complex products, advanced nanotechnology (sometimes referred to as molecular manufacturing) will make use of positionally-controlled mechanochemistry guided  by molecular machine systems. Formulating a roadmap for development of  this kind of nanotechnology is now an objective of a broadly based technology roadmap project led by Battelle (the manager of several U.S. National Laboratories) and the Foresight Nanotech Institute.
Shortly after this envisioned molecular machinery is created, it will result in a manufacturing revolution, probably causing severe disruption. It also has serious economic, social, environmental, and military implications.

Four Generations

Mihail (Mike) Roco of the U.S. National Nanotechnology Initiative has described four generations of nanotechnology development (see chart below). The current era, as Roco depicts it, is that of passive nanostructures, materials designed to perform one task. The second phase, which we are just entering, introduces active nanostructures for multitasking;  for example, actuators, drug delivery devices, and sensors. The third  generation is expected to begin emerging around 2010 and will feature  nanosystems with thousands of interacting components. A few years after  that, the first integrated nanosystems, functioning (according to Roco)  much like a mammalian cell with hierarchical systems within systems, are expected to be developed.

Some experts may still insist that  nanotechnology can refer to measurement or visualization at the scale of  1-100 nanometers, but a consensus seems to be forming around the idea (put forward by the NNI’s Mike Roco) that control and restructuring of matter at  the nanoscale is a necessary element. CRN’s definition is a bit more  precise than that, but as work progresses through the four generations  of nanotechnology leading up to molecular nanosystems, which will  include molecular manufacturing,  we think it will become increasingly obvious that „engineering of  functional systems at the molecular scale” is what nanotech is really  all about.

(Author: Kalyan Gupta, Jawaharlal Nehru Technological University, Hyderabad; Source: http://www.quora.com/Kalyan-Gupta/Posts/What-is-Nano-science-technology)