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11.09
Nanotech: Engineering from the Bottom Up
By George
W. Zobrist
The nanotechnology concept was
first introduced in a famous lecture given by
Dr. Richard Feynman at an American Physical
Society meeting held at Caltech in 1959. While
the talk predated by nearly two decades the term
nanotechnology, Feynman discussed the
possibility of manipulating individual molecules
and atoms to produce useful end products. The
term nano-technology was coined by Prof.
Norio Taniguchi in a 1974 paper describing
semiconductor processes on the order of a
nanometer. One nanometer is equal to
one-billionth of a meter. To put this scale in
context, one can compare a nanometer to a meter,
as a marble to the size of the earth.
Nanotechnology today is defined
as the study/application of structures on a
molecular/atomic scale. Nanotech's purpose is to
create new structures through self-assembly — a
bottom up approach, rather than top-down. A
number of physical phenomena become pronounced
as the size of the system decreases. For
example, if one keeps halving aluminum, it can
become highly reactive, if the halving reaches
to the nano scale. Until then it is still
aluminum. Materials reduced to nanoscale
exhibit different properties — opaque substances
become transparent (copper), stable materials
become combustible (aluminum), solids turn
into liquids at room temperature (gold).
A number of physical properties
are changed when materials are reduced to
nanoscale. Thus one can introduce the concept of
self-assembly, producing new structures through
a bottom up approach. The challenge is to
engineer useful structures in addition to the
natural ones. One of the powers, postulated, is
that it will produce not only better products,
but a vastly improved manufacturing process
through the personal nanofactory. Nanotechnology
not only allows the making of quality products,
but one can envision making new nanofactories at
a very low cost and rapidity.
Mike Rocco (U. S. National
Nanotechnology Initiative) categorizes
nanotechnology development into four
generations:
-
Passive nanostructures —
aerosols, coatings, ceramics
-
Active nanostructures —
targeted drugs, amplifiers
-
Systems of nanosystems —
guided assemblies, robotics
-
Molecular nanosystems —
molecular devices, atomic designs
Presently, we are in the first
generation and just entering the second
generation. Military uses will emerge, as well
as commercial uses. Hence, not only benefits for
humanity — but also potential grave risks.
According to the
Project on
Emerging Nanotechnologies, as of 25 Aug. 2009,
more than 1,000 nanotechnology-enabled
products are available to consumers around the
globe. These
include items such as: titanium oxide in
sunscreen, cosmetics and some food products;
carbon allotropes (carbon nanotubes) for gecko
tapes; silver in food packaging, just to name a
few. These are mostly passive “first generation”
nano materials. It is also apparent that many
so-called nano products are sometimes little
related to the actual premise of molecular
engineering goals. It is estimated that the
later generation concepts are 20 to 30 years on
the horizon, according to the Center for
Responsible Nanotechnology (CRN).
Nanotechnology is so new that
predictions range from the ability to reproduce
diamonds and food, to the world being devoured
by self-replicating nanorobots.
What are some of the postulated
benefits of molecular manufacturing? Molecular
manufacturing should let us get essentially
every atom in place; make the structure
consistent with laws of physics; manufacturing
costs not greatly exceeding raw material and
energy costs ; and massive parallelism.
Computers and display devices would become
stunningly cheap; building of light/strong
electrical equipment would allow use of solar
thermal power as a primary energy source;
advanced equipment for medical research.
Physical filters for purifying water can be
constructed on a nanoscale, so that pores can
remove 100 percent of bacteria, viruses, etc.
An area of concern resulting
from molecular manufacturing is the possibility
of extremely lethal weapons. Guns could be more
powerful; nanotech antipersonnel weapons could
contain large amounts of toxin, such as,
botulism and be injected into humans through a
small robotic insect carrying the toxins.
Nanotechnology is an emerging
technology which promises to lead us to the next
Industrial Revolution. Presently there is on the
order of $ 15 billion in federal research
investment.
According to Tim Harper, writing
in IOP Nanotechnology 2003, “one can take
a random selection of scientists, engineers,
investors and the general public and ask them
what nanotechnology is and you will receive a
range of replies as broad as nanotechnology
itself. For many scientists, it is nothing
startlingly new. For most other groups, however,
nanotechnology means something far more
ambitious, miniature submarines in the
bloodstream, little cogs and gears made out of
atoms, space elevators made of nanotubes, and
the colonization of space. It is no wonder
people often muddle up nanotechnology with
science fiction.”
It is increasingly common to
hear people referring to the nanotechnology
industry, just like the software or mobile phone
industries, but will such a thing ever exist?
Many of the companies working with
nanotechnology are simply applying knowledge of
the nanoscale to existing industries.
J. L. Tucker writing in IEEE
Nanotechnology Magazine (Sept. 2008) states that
standards are needed to achieve a high degree of
interoperability, create order in the
marketplace, simplify production requirements,
manage the potential for adverse environmental
impact, and ensure the safety and health of
those developing and using nanotechnology. This
is true even though we are years away from the
more sophisticated electronic and medical
devices envisioned. The gold in nanotechnology
will be for those that develop the next best
material, or the next electronic component which
is cheaper/faster than today’s CMOS technology.
The wealth potential is waiting out there.
Naysayers are already painting pictures of doom
and gloom for the environment. By taking action
now with proper terminology, test measurement
methods, reporting, and environmental, safety,
and health safeguards, doom and gloom may be
prevented for the environment.
Following are just a few of the
Web sites available for learning more about
nanotechnology:
One should be warned this is not
“light” reading and has a Sci-Fi flavor to it!
Dr. George W. Zobrist is
professor emeritus at the University of
Missouri-Rolla, Department of Computer Science,
IEEE-USA's Member Activities editor, and former
editor of IEEE Potentials.
Comments may be submitted to
todaysengineer@ieee.org.
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