Nanotechnology
1. What is nanotechnology?
Nanotechnology
is molecular manufacturing or, more simply, building things one atom or molecule
at a time with programmed nanoscopic robotarms. A nanometer is one billionth of
a meter (3 - 4 atoms wide). Utilizing the well understood chemical properties of
atoms and molecules (how they "stick" together), nanotechnology
proposes the construction of novel molecular devices possessing extraordinary
properties. The trick is to manipulate atoms individually and place them exactly
where needed to produce the desired structure. This ability is almost in our
grasp.
Nanotechnology is
often called the science of the small. It is concerned with manipulating
particles at the atomic level, usually in order to form new compounds or make
changes to existing substances. It is being applied to problems in
electronics, biology, genetics and a wide range of business applications.
Thus,
Nanotechnology can best be considered as a 'catch-all' description of
activities at the level of atoms and molecules that have applications in the
real world.
2.
Why
"nano"?
Nano comes from the Greek word for small and it is used to indicate one-billionth or 10-9 power. Nanoscience and nanotechnology was originally advanced as the next frontier after micro-technology which worked in realm of microns (one- millionth of a meter). Since an atom is roughly about ten nanometers, the term has come to be applied to the general study of molecular and atomic particles. A nanometre is a billionth of a metre, that is, about 1/80,000 of the diameter of a human hair, or 10 times the diameter of a hydrogen atom.
3. Two Styles Of Technology - A
Background:
The ancient style of
technology that led from flint chips to silicon chips handles atoms and
molecules in bulk and can be called bulk technology. The new technology
will handle individual atoms and molecules with control and precision and it can
be called molecular technology. It will change our world in more ways
than we can imagine.
Microcircuits have parts measured in micrometers - that is, in millionths of a meter - but molecules are measured in nanometers (a thousand times smaller). We can use the terms "nanotechnology" and "molecular technology" interchangeably to describe the new style of technology. The engineers of the new technology will build both nanocircuits and nanomachines. This technology will be based on mechanical assembly of molecules to build complex structures, that is, the use of molecular machinery to perform mechanosynthesis for molecular manufacturing.
A short summary of what molecular nanotechnology will mean is thorough, inexpensive control of the structure of matter based on molecule-by-molecule control of products and byproducts; the products and processes of molecular manufacturing.
4. The Fundamentals:
Manufactured products are made from atoms. The properties of those products depend on how those atoms are arranged. If we rearrange the atoms in coal we can make diamond. If we rearrange 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. Todays manufacturing methods are very crude at the molecular level. Casting, grinding, milling and even lithography move atoms in great thundering statistical herds.
In the future,
nanotechnology will let us snap together the fundamental building blocks of
nature easily, inexpensively and in almost any arrangement that we desire and
will also let us fabricate an entire new generation of products that are
cleaner, stronger, lighter, and more precise.
Whatever we call it, it should let us -
·
Get essentially every atom in the right place.
·
Make almost any structure consistent with the laws of physics and
chemistry that we can specify in atomic detail.
·
Have manufacturing costs not greatly exceeding the cost of the required
raw materials and energy.
5. What are "Nanocrystals" ?
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Nanocrystals are the building blocks of nanotechnology. A nanocrystal is formed by combining two or more inorganic
substances, sometimes with only a single molecule of each substance.
Nanocrystals have been formed with a variety of different elements; the
challenge researchers are facing now is to control their size and shape. A
string of nanocrystals is called a nanotube. Advanced research is looking at
combinations of silicon and germanium to produce computer memory. Some of the
first commercial nanocrystals combine aluminum and silica to produce
commercial-grade coatings providing resistance to heat and rust.
There are two more concepts
commonly associated with nanotechnology:
· Positional assembly.
·
Self-replication.
The need for positional assembly implies an interest in molecular robotics, e.g., robotic devices that are molecular both in their size and precision. These molecular scale positional devices are likely to resemble very small versions of their everyday macroscopic counterparts. Positional assembly is frequently used in normal macroscopic manufacturing today, and provides tremendous advantages. We need to apply at the molecular scale the concept that has demonstrated its effectiveness at the macroscopic scale: making parts go where we want by putting them where we want!
The requirement for low cost creates an interest in self replicating manufacturing systems able both to make copies of themselves and to manufacture useful products. If we can design and build one such system the manufacturing costs for more such systems and the products they make (assuming they can make copies of themselves in some reasonably inexpensive environment) will be very low.
For Example: Nanogears no more than a nanometer wide (as shown in the picture above) could be used to construct a matter compiler, which could be fed raw material to arrange atoms and build a macro-scale structure.
6. How advanced is
it Today?
Scientists and engineers still
have no direct, convenient way to control molecules, basically because human
hands are about 10 million times too large. Today, chemists and materials
scientists make molecular structures indirectly, by mixing, heating, and the
like. The idea of nanotechnology begins with the idea of a molecular assembler, a device resembling an industrial robot arm but built on a
microscopic scale. A general-purpose molecular assembler will be a jointed
mechanism built from rigid molecular parts, driven by motors, controlled by
computers, and able to grasp and apply molecular-scale tools. Molecular
assemblers can be used to build other molecular machines–they can even build
more molecular assemblers. Assemblers and other machines in molecular
manufacturing systems will be able to make almost anything, if given the right
raw materials. In effect, molecular assemblers will provide the microscopic
"hands" that we lack today.
Digital electronics brought an
information-processing revolution by handling information quickly and
controllably in perfect, discrete pieces: bits and bytes. Likewise,
nanotechnology will bring a matter-processing revolution by handling matter
quickly and controllably in perfect, discrete pieces: atoms and molecules. The
digital revolution has centered on a device able to make any desired pattern of
bits: the programmable computer. Likewise, the nanotechnological revolution will
center on a device able to make (almost) any desired pattern of atoms: the
programmable assembler. The technologies that plague us today suffer from the
messiness and wear of an old phonograph record. Nanotechnology, in contrast,
will bring the crisp, digital perfection of a compact disc.
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Along that path there is still a lot of improvement to be made in design techniques. When they are improved one could build machines, not just things that fold, but things that fold to form objects that do something, and use those machines to build better machines. We know by looking at nature that molecular machines can, by holding reactive molecules at particular positions and orientations, perform chemical operations to build up complex structures in specific ways. That is the function of enzymes at one end of a spectrum of machines. If you have more flexible, programmable machines, they start to look more and more like general purpose assemblers.
Studies of nanotechnology are
today in the exploratory
engineering phase, and just beginning to move into engineering
development. The basic idea of exploratory engineering is simple: combine
engineering principles with known scientific facts to form a picture of future
technological possibilities. Exploratory engineering looks at future
possibilities to help guide our attention in the present. Science–especially
molecular science–has moved fast in recent decades. There is no need to wait
for more scientific breakthroughs in order to make engineering breakthroughs in
nanotechnology.
A push is well underway to invent devices that manufacture at almost no cost, by treating atoms discretely, like computers treat bits of information. This would allow automatic construction of consumer goods without traditional labor, like a Xerox machine produces unlimited copies without a human retyping the original information.
To imagine molecular machines, one must first picture molecules. We can picture atoms as beads and molecules as clumps of beads, like a child's beads linked by snaps. Atoms are rounded like beads, and although molecular bonds are not snaps, our picture at least captures the essential notion that bonds can be broken and reformed.
Biochemists dream of designing and building such devices, but there are
difficulties to be overcome. Engineers use beams of light to project patterns
onto silicon chips, but chemists must build much more indirectly than that. When
they combine molecules in various sequences, they have only limited control over
how the molecules join.
7. How could it be made to work for us ?
Nanotechnology will probably be developed, one way or another. The challenge for speculation, and for technical and social invention, is how it may be used. The potential impacts of nanotechnology are immense. Shrinking computer components to atomic scale could enable computers to continue to grow cheaper, smaller, and more powerful for decades hence. Tiny nanomachines could monitor and make repairs inside cells, curing disease and extending life.
Molecular assemblers might
build materials to order, making matter as controllable and easily reproduced as
software while also disassembling wastes
and pollution to recover elements and compounds for reuse.
A.
Factory
Factories -
Using fast, precise machines to
handle matter in molecular pieces makes it easy for nanotechnology to be fast,
clean, and efficient. But for it to be cheap,
the manufacturing equipment has to be cheap. Molecular-manufacturing equipment
can be used to make all the parts needed to build more molecular manufacturing
equipment. It can even build the machines needed to put the parts together. This
resembles an idea developed by NASA for a self-expanding manufacturing complex
on the Moon, but made faster and simpler using molecular machines and parts.
B.
Replicators -
One way to build a lot of
molecular manufacturing equipment in a reasonable time would be to make a
machine that can be used to make a copy of itself, starting with special but
simple chemicals. A machine able to do this is called a "replicator."
With a replicator and a pot full of the right fuel and raw materials, you could
start with one machine, then have two, four, eight, and so on.
C.
General
Assemblers -
The most likely path to
nanotechnology leads to assemblers with more and more general capabilities.
D.
Building with Assemblers
Assemblers can be made to work based on
pointing to things a lot like them that already do work. Chemistry shows us a
wide range of reactions that can be made to occur when molecules come together
in the right positions and orientations. Enzymes show that if you hold reactive
molecules together, in a particular position and orientation, you can get a
particular reaction to occur. What is needed to build complex structures is
systematic positioning of molecules to make reactions occur in very specific and
very complicated patterns. That is what
assemblers will accomplish by using the kinds of tools we are already familiar
with. The important addition is that, instead of being a specific jig that can
only catalyze one reaction, as an enzyme is, we are talking about things that
can do programmable positioning; something that is a general purpose, flexible
tool for construction. And, as icing on the cake, it will then be possible to
drive a lot of these reactions using external sources of energy, such as
voltage, or even mechanical force by means of the molecular machines involved.
E.
Nano-Scale Mechanical Computers
They will be vastly superior to
the kinds of computers that I am designing. I would guess, off hand, that these
molecular electronic computers will be three orders of magnitude faster than my
molecular mechanical device.
F.
Cell Repair Machines
Today, one mode of therapy is to throw drug molecules into the body: they
diffuse around and selectively stick to things and perturb the behavior of the
biological structures. The other major mode of therapy is to take an enormous
piece of metal and hack through tissue, ignoring entirely where the cells are.
The result is that the body abandons its dead and self-heals -- if things go
well. Technology like this, however, would bring surgical control to the
molecular level, which means tissue could be either healed or reconstructed --
again, if you have the software to handle the task, and there are arguments that
such is achievable, though the arguments are in the software domain.
8. What is in future for it ?
Nanotechnology has many proponents with many different views of what
nanotechnology is. The different viewpoints range from extensions of current
technologies in computer chips to visions of nanotechnology as the supreme
ability to manipulate matter. But probably, nanotechnology will eventually
be somewhere in between. Molecular nanotechnology will
give thorough control of matter on a large scale at low cost, shattering a whole
set of technological and economic barriers more or less at one stroke.
The world is on the brink of a
new technological revolution beyond anyhuman experience. A new, more powerful
industrial revolution capable ofbringing wealth, health, and education, without
pollution, to every personon the planet. No longer will forest need to be cut or
smoke spewed intothe air. This is the promise of nanotechnology.
