Nanotechnology refers broadly to a field of
applied science and
technology whose unifying theme is the control of matter on the atomic and molecular
scale, normally 1 to 100 nanometers, and the fabrication of devices within that
size range. It is a highly multidisciplinary field, drawing from fields such as
applied physics,
materials science, interface and colloid science,
device physics, supramolecular
chemistry (which refers to the area of chemistry that
focuses on the no covalent bonding interactions of molecules), chemical
engineering, mechanical engineering, and electrical engineering. Much
speculation exists as to what may result from these lines of research.
Nanotechnology can be seen as an extension of existing sciences into the
nanoscale, or as a recasting of existing sciences using a newer, more modern
term.
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. The impetus for nanotechnology comes
from a renewed interest in Interface and Colloid Science, coupled with a new
generation of analytical tools such as the atomic force microscope (AFM), and
the scanning tunneling microscope (STM). Combined with refined processes such
as electron beam lithography and molecular beam epitaxy, these instruments
allow the deliberate manipulation of nanostructures, and led to the observation
of novel phenomena.
Examples of nanotechnology in modern use are the manufacture of polymers
based on molecular structure, and the design of computer chip layouts based on
surface science. Despite the great promise of numerous nanotechnologies such as
quantum dots and nanotubes, real commercial applications have mainly used the
advantages of colloidal nanoparticles in bulk form, such as suntan lotion, cosmetics,
protective coatings, drug delivery and stain resistant clothing.
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