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15-10-2010, 03:07 PM

.ppt   Nanomachines_Chris_Romo.ppt (Size: 223.5 KB / Downloads: 121)
Material Science
Christopher Romo


A nanomachine, also called a nanite, is a mechanical or electromechanical device whose dimensions are measured in nanometers (millionths of a millimeter, or units of 10-9 meter).


During the 1980’s and 1990’s, K. Eric Drexler popularized the potential for nanomachines..
The ultimate goal of nanomachine technology is to build an “assembler” nanomachine that is designed to manipulate matter at the atomic level.
The “assembler” would be able to rearrange atoms from raw materials in order to produce useful items.
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08-01-2011, 09:27 AM


Nanotechnology is the manipulation of matter on the nanoscale. A nanometer is a very small measure of length-it is one billionth of a meter, a length so small that only three or four atoms lined up in a row would be a nanometer. So, nanotechnology involves designing and building materials and devices where the basic structure of the material or device is specified on the scale of one or a few nanometers. Ultimately, nanotechnology will mean materials and devices in which every atom is assigned a place, and having every atom in the right place will be essential for the functioning of the device.

The kinds of product that could be built will range from microscopic, very powerful computers to super strong materials ten times as strong as steel, but much lighter too, food to other biological tissues. All these products would be very inexpensive because the molecular machines that built them will basically take atoms from garbage or dirt, and energy from sunshine, and rearrange those atoms into useful products, just like trees and crops take dirt, water and sunshine and rearrange the atoms into wood and food.

Nanotechnology cannot be defined as a definite branch of science but different from the conventional ones that we have as of now. It is set to encompass all the technological aspects that we have today and is nothing but the extension of scientific applications to a microscopic scale and thereby reaching closer to perfection if not right there.

.doc   Nanomachines.doc (Size: 225 KB / Downloads: 67)



The mechanical applications of nanotechnology are immense as it is in any other technological field. This paper concentrates on certain applications of interest viz. Carbon Nanotubes, Nanomachines and other related fields.

Carbon nanotubes are cylindrical molecules with dimensions in the range of nanometers. They are constituted of carbon atoms only, and can essentially be thought of as a layer of graphite rolled-up into a cylinder. They have an impressive list of attributes. They can behave like metals or semiconductors, can conduct electrically better than copper, can transmit heat better than diamond, and they rank among the strongest materials known- not bad for structures that are just a few nanometers across. Several decades from now we may see integrated circuits with components and wires made from nanotubes and may be even buildings that can snap back into shape after an earthquake.

Nanomachines are extremely small machines which are built from individual atoms. During the 1980’s and 1990’s, futurist and visionary K.Eric Drexler popularized the potential of nanomachines. ‘Nanomachines’ include replicas of present day machines(nanogears,nanopumps etcWink as well as new machines that do not have analog in the present world, like the assembler. The assembler is a nanomachine designed to manipulate matter as the atomic level.

M.E.M.S OR Micro Electronic Mechanical Systems, Nano tools, the Biotechnology, Nanotechnology interface, Nanomedicines and Quantum Computing are some of the fields falling close to the above discussed and this paper throws light into these aspects.


In 1991, a Japanese scientist Sumio Iijima used a high-resolution transmission electron microscope to study the soot created in an electrical discharge between two carbon electrodes at the NEC Fundamental Research Laboratory in Tsukuba, Japan. He found that the soot contained structures that consisted of several concentric tubes of carbon, nested inside each like Russian dolls. These were termed as ‘Carbon Nanotubes’.

Later efficient ways of making large quantities of these multiwall nanotubes were developed. Subsequently, 1993, single-wall nanotubes were tens of nanometers across, the typical diameter of a single-wall nanotube was just one or two nanometers. The past decade has seen an explosion of research into both types of nanotube.

Today, nanotubes can be grown efficiently by the catalytic decomposition of a reaction gas that contains carbon, with iron often being used as the catalyst. This process has two main advantages. First, the nanotubes are obtained at much lower temperature, although this is at the cost of lower quality. Second, the catalyst can be grown on a substrate, which allows novel structures, such as ‘nanobrushes’, to be obtained. Currently nanotubes can be grown to lengths exceeding 100 microns, and in various shapes such as ‘nanosprings’.

A nanotube can be considered as a single sheet of graphite that has been rolled up into a tube. The electronic properties of the resulting nanotube depend on the direction in which the sheet was rolled up. Some nanotubes are metals with high electrical conductivity, while others are semiconductors with relatively large band gaps. Nanotubes also have remarkable mechanical properties that cam be exploited to strengthen materials or to act as ‘tips’ in scanning probe microscopes. And since they are composed entirely of carbon, nanotubes also have a low specific weight.


In a sheet of graphite each carbon atom is strongly bonded to three other atoms, which makes graphite very strong in certain directions. However, adjacent sheets are only weakly bound by vander waals forces, so layers of graphite can be easily pealed apart as happens when writing with a pencil. As we shall see, it is not easy to peel a carbon layer from a multiwall nanotube. Carbon fibre is already used to strengthen a wide range of materials, and the special properties of carbon nanotubes mean that they could be the ultimate high strength fibre.

Lieber and his co-workers went on to explore larger forces and deformations and compared carbon nanotubes with nanorods made from silicon carbide, another very strong material. What they found was surprising whereas the silicon-carbide nanorods eventually fractured the multiwall carbon nanotubes buckled, but did not break. This behaviour has since been confirmed in several experiments in which the nanotubes are either bent or compressed along their length.

Carbon nanotubes got a peculiar feature that they first bend over to surprisingly large angles, before they start ripple and buckle, and then finally develop kinds as well. The amazing thing about the carbon nanotubes is that these deformations are elastic- they all disappear completely when the load is removed.

To see how these properties might be useful, imagine owning a BMW car made from carbon nanotubes and being unlucky enough to crash into a wall. Due to high force of the impact, the nanotubes would bend and then buckle, squeezing your BMW into the shape of something like a Volkswagen Beetle. This would happen relatively long distance, which would provide an effective ‘crunch zone’. Moreover, after the crash all the buckles and kinks would unfold and your BMW would ‘reappear’ as if nothing had happened! To be completely safe, however, the nanotubes would have to be combined with energy-absorbing materials, otherwise the collision between the car and the wall would be completely elastic and you would rebound from the wall with the same speed as you hit it! Other, less futuristic applications might include light weight bullet proof vests and earthquake-resistant buildings, while nanotubes tips for scanning probe microscopes are already commercially available.

The high strength of carbon nanotubes makes them promising candidates in reinforcement applications but there are many outstanding problems that must be overcome. First, the properties of the individual tubes must be optimized. Second, the tubes must be efficiently bonded to the material they are reinforcing so that they actually carry the loads. Third, the load must be distributed within the nanotube itself to ensure that the outermost layer does not shear off.



Nanomachines are machines of dimensions in the range of nanometers. They include micro scale replicas of present day machines like the nanogears,nanoarms or the nanorobots as well as futuristic machines which have no present day analogs, like the assembler which can assemble atoms to produce further machines or assembler themselves.

Though there can be analogous of today’s mechanical components, the way in which both these categories are manufactured will be entirely in contrast to each other with regard to what we an call as the direction of manufacturing While today’s machines are manufactured by the top-bottom approach in which they are machined down from larger components or bulk of the component materials , nanomachines will be manufactured by the bottom-top approach where they are built atom by atom, placing the individual atoms precisely at the required positions.

No nanomachines in the true sense have yet been manufactured, although feasibility of producing several of them is confirmed by various means. The main difficulty lies in the inability of today’s handling facilities to account for manipulating such sub atomic particles. Producing them by means of chemical reactions is the most apt one for controlling atomic positions. Scientists have been able to obtain virtual machines by means of computer simulated chemical reactions and this proves their feasibility. The distance from actually making them will be bridged by finding way to control and predict the outcome of chemical reactions more quickly and precisely.






The present generation micromachines which fall in the category of nanomachnes in the sense that they are made by molecular technology are currently synthesized by means of chemical reactions. As of now, chemical synthesis is conducted almost exclusively in solution, where reagent molecules move by diffusion and encounter one another in random positions and orientations.
The prominent synthesizing techniques can be classified as follows-

1. Solution-phase synthesis
2. Enzymatic synthesis
3. Mechanosynthesis
4. Biosynthesis

Solution-phase synthesis poses familiar problems of reaction specificity. Although many small-molecule reactions proceed cleanly and have high yields, large molecules with many functional groups present multiple potential reaction sites and hence, can be converted into multiple products.

Although a spectrum of intermediate cases can be identified, enzymatic synthesis differs significantly from the standard solution-phase model. Enzymatic reactions begin with reagent binding, which places molecules in well-controlled positions and orientations. The resulting high effective concentrations resulting high reaction rates.
Mechanosynthesis differs from enzymatic catalysis, yet many of the same principles apply. One can perform mechanosynthesis by using macroscopic devices, such as scanning tunneling and atomic force microscope (STM and AFM) mechanisms. The first clear example of a mechanically controlled synthesis was the arrangement of 35 Xenon atoms on a nickel crystal to spell ‘IBM’.
Biosynthesis involves synthesize of biological materials.


If scientists manage to build nanomachines that can rearrange atoms, the assemblers, a world of exciting possibilities will open up. Purpose designed nanomachines could be used to provide breakthrough treatments for many diseases. Medical nnaomachines programmed to recognize and disassemble cancerous cells should be injected into the blood stream of cancer suffers, thus providing a quick and effective treatment for all types of cancer. Nanomachines would be used to repair damaged tissues and bones. They could even be used to strengthen bones and muscle tissue by building molecular support structures by reassembling nearby tissue. With the ability to manipulate human cells at the atomic level, medical science will rapidly devise treatments for most human illness. And since nanomachines will be designed to make copies of them, these treatments will be inexpensive and available to the entire population.

Food shortage and starvation will be a thing of the past if nanotechnology is perfected. Nanomachines will be able to turn any material into food, and this food could be used to feel millions of people world wide. Again, since the technology is self replicating, food produced by nanomachines will be low cost and available to all.

As well as food, nanomachines will be able to build other items to satisfy the demands of our growing population of consumers. Clothing, houses, cars, television and computers will be readily available at virtually no cost. Furthermore, there will be no concern about the garbage produced by the new consumerist society because nanomachines will convert it all back into new consumable goods.

Environmental problems such as ozone depletion and global warming could be solved with nanotechnology. Swarms of nanomachines would be released into the upper atmosphere. Once there, they could systematically destroy the ozone depleting chlorofluorocarbons (CFCs) and built new ozone molecules out of water and carbon dioxide. Ozone is built out of 3 oxygen atoms, and since water and carbon dioxide both contain oxygen, the atmosphere contains a plentiful supply of oxygen atoms. While the ozone construction teams are at work in the upper atmosphere, teams of specialized nanomachines would be employed to destroy the excess carbon dioxide in the lower atmosphere. Carbon dioxide is a heat trapping gas, which has been identified as one of the major contributors to global warming. Removing excess carbon dioxide could help halt global warming and bring the planet’s ecosystem back into balance. This will benefit all species on Earth.

The perfection of nanotechnology and the production of nanomachines would herald a new age for humanity. Starvation, illness and environmental problems could quickly come to an end. But how realistic are the goals of nanotechnology? Will it ever be possible to produce machines the size of atoms? And if so, how feasible is it to build nanomachines that can build copies of themselves? Before we get carried away the promises of nanotechnology, we should take a look at some of the problems that are yet to be solved.



An important challenge to overcome is one of engineering. How can we physically build machines out of atoms? Rearranging atoms into new shapes is essentially building new molecules and this is no easy task. Using contemporary technology to rearrange atoms has been said to be analogous to assembling LEGO blocks while wearing boxing gloves. It is virtually impossible to snap individual atoms together. All we can do is crudely push large piles of them together and hope for the best. Scientists hope that once this initial challenge is overcome, nanomachines will usher in a new age of molecular engineering and previous problems will be a thing of the past. The new machine will allow scientists to take off the boxing gloves and accurately snap together individual atoms to build virtually any molecule.

This is nice in principle, but the question of how to build the first nanomachines remains. Nanotechnology thinks that it will be impossible to build the first nanomachine by using large-scale equipment. Although progress is being made in the miniaturization of integrated circuits and in the ultra-fine finishing of high quality optical components, the large-scale technology being used doesn’t let us take off the boxing gloves. There is a limit to how far down these machines can go. Super smooth lens polishing is one thing, but moving individual atoms is something else all together. Nanotechnology need to get the boxing gloves of f before they can build the first nanomachines.

One way to work without boxing gloves is to patiently experiment wit chemical synthesis. The idea is to build molecules of increasing complexity by allowing atoms to assemble to rearrange in natural ways. When molecules are mixed, they naturally form new molecules. Through extensive experimentation, more control can be gained over how molecules are formed. In time, it is conceivable them chemists will be able to position individual atoms using a range of techniques developed in chemical synthesis. Chemical synthesis is promising. In computer simulations, molecularly stable gears and cogs have been formed through chemical synthesis.

If chemist and engineers succeed in building nanomachines the hope is that these machines will be able to build a whole range of new molecules from the atom up. If all goes well, scientists will never have to move atoms round while wearing boxing gloves and the lengthy experimental process of chemical synthesis will no longer be required. But will it be that easy?

In order to make new molecules, a nanomachine has to somehow ‘grab individual atoms with its pincers and move them into new positions or attach them to other molecules. There are serious problems that need to be overcome. Consider, for example, the fact that a nanomachine’s pincers will be made out of several atoms and will therefore be larger than the individual atoms that it needs to move around. This means that the intricacy and accuracy of the nanomachines movement will be severely limited. It will be clumsy. Assembling atoms would be like trying to piece together a mechanical wristwatch with your fingers rather than small tweezers.

Another problem arises from the fact that individual atoms are compelled to ‘attach’ to other atoms. Some atomic bonds can be extremely strong (especially with carbon atoms) so pulling them apart will require large amounts of energy. Furthermore, since carbon atoms attach to just about anything it seems likely that they will bond to nanomachine’s pincers after they have been pried away from their original molecules. The only way to remove them could be to move them to molecules that they are more strongly attracted to. But then there is the possibility that the entire nanomachine will stick to the molecule. The situation is analogous to trying to build a wristwatch with magnetized tweezers and screw drivers. It can’t be done because the individual components stick to the tools. However recent developments indicate that the type of work being done now will hopefully lead to more complex manipulation of atoms, and this could result in the development of tools that successfully ‘pick and place’ carbon atoms. As our technological capacities develop, the promise of nanomachine technology becomes more of a reality. We may one day see the successful creation of nanomachine assemblers. These machines could end hunger and bring in a new age of advancement for humanity. Nanotechnology offers us big promises in a small package. However, the advantages promises do not come for free. They come with some very big risks.

More importantly there is a contrasting possibility that may arise with the advent of neo-nanotech age. It can bring forth revolutionary changes to the whole existence of humanity and the universe. Apart from the technological impacts, it can affect the socio-economic order and more importantly there are problems regarding ethics at stake. Consider for example, the self replicating feature, if incorporated will have far reaching consequences that may prove to be fatal instead of going the other way. Just like a nuclear fission, to lend an example from the yester world, it could be used constructively or destructively as the hands that turn the wheels decide. It won’t take a genius to turn the engines of creation to the engines of destruction.


All the applications mentioned in this paper exhibit a wealth of properties and phenomena. While many of these are understood, others remain controversial, and all these fields are sure to remain an exciting area of science for years to come. The amazing predictions discussed are not in doubt. Like any new technology, however many of these have to outperform current technologies to gain a foothold. All these challenges will keep researchers busy for a long time to come.

While there is many challenging goal, there appear to be no fundamental barriers to achieving it. A proper marriage of physics, chemistry and various engineering fields may be up to the task. Then nanotechnology would undoubtedly spark a series of industrial revolutions that may transform our lives to a far greater extend than any other single field of applied science has ever done in the past. And in science as so often in life, big surprise comes in small packages.


Engines of creation, Machine phase Nanotechnology Dr.K.ERIC DREXLER
Caltech university lecture by – RICHARD FEYNMAN
Unbounding the future: the nanotechnological
revolution- Dr.K.ERIC DREXLER
Nano –And Micro-Electromechanical Systems
fundamentals of Micro-And Nano Engineering- S.E.L.Y.SHEWSKI,CRC
PRESS, 2000
Molecular Engineering, Mechanical Engineering Dr.MIHALI ROCCO
Self Replicating Systems and Molecular Manufacturing RALPH C MERKLE
Journal of the British Interplanetary Society
Little big science GARY STIX

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21-03-2011, 09:45 AM

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A nanomachine, also called a nanite, is a mechanical or electromechanical device whose dimensions are measured in nanometers (millionths of a millimeter, or units of 10-9 meter).
During the 1980’s and 1990’s, K. Eric Drexler popularized the potential for nanomachines..
The ultimate goal of nanomachine technology is to build an “assembler” nanomachine that is designed to manipulate matter at the atomic level.
The “assembler” would be able to rearrange atoms from raw materials in order to produce useful items.
The most important challenge to overcome is one of molecular engineering. Rearranging atoms into new shapes is essentially building new molecules.
Through experimentation, more control could be gained on how molecules are formed.
In time, chemists will be able to position individual atoms by techniques developed in chemical synthesis.

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