Nanotechnology Basics: For Students and Other Learners
"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
- Common Questions on Nanotechnology
- CRN Student Research Project
- Nanotechnology Education Group
- Student Pugwash Nanotech Page
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Nanotechnology is the engineering of tiny machines — the projected ability to build things from the bottom up inside personal nanofactories (PNs), using techniques and tools being developed today to make complete, highly advanced products. Ultimately, nanotechnology will enable control of matter at the nanometer scale, using mechanochemistry. 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.
A nanometer is one billionth of a meter, roughly the width of three or four atoms. The average human hair is about 25,000 nanometers wide.
It’s a proposed new appliance, something that might sit on a countertop in your home. To build a personal nanofactory (PN), you need to start with a working fabricator, a nanoscale device that can combine individual molecules into useful shapes. A fabricator could build a very small nanofactory, which then could build another one twice as big, and so on. Within a period of weeks, you have a tabletop model.
Products made by a PN will be assembled from nanoblocks, which will be fabricated within the nanofactory. Computer aided design (CAD) programs will make it possible to create state-of-the-art products simply by specifying a pattern of predesigned nanoblocks. The question of when we will see a flood of nano-built products boils down to the question of how quickly the first fabricator can be designed and built.
MOVIE TIME: A short film called Productive Nanosystems: from Molecules to Superproducts depicts an animated view of a nanofactory and demonstrates key steps in the sample process that converts basic molecules into a billion-CPU laptop computer. The 4-minute streaming video is online here.
|Lifesaving medical robots or untraceable weapons of mass destruction.|
|Networked computers for everyone in the world or networked cameras so governments can watch our every move.|
|Trillions of dollars of abundance or a vicious scramble to own everything.|
|Rapid invention of wondrous products or weapons development fast enough to destabilize any arms race.|
It’s a bit like enzymes (if you know your chemistry): you fix onto a molecule or two, then twist or pull or push in a precise way until a chemical reaction happens right where you want it. This happens in a vacuum, so you don’t have water molecules bumping around. It’s a lot more controllable that way.
So, if you want to add an atom to a surface, you start with that atom bound to a molecule called a “tool tip” at the end of a mechanical manipulator. You move the atom to the point where you want it to end up. You move the atom next to the surface, and make sure that it has a weaker bond to the tool tip than to the surface. When you bring them close enough, the bond will transfer. This is ordinary chemistry: an atom moving from one molecule to another when they come close enough to each other, and when the movement is energetically favorable. What’s different about mechanochemistry is that the tool tip molecule can be positioned by direct computer control, so you can do this one reaction at a wide variety of sites on the surface. Just a few reactions give you a lot of flexibility in what you make.
MECHANOSYNTHETIC REACTIONS Based on quantum chemistry by Walch and Merkle [Nanotechnology, 9, 285 (1998)], to deposit carbon, a device moves a vinylidenecarbene along a barrier-free path to bond to a diamond (100) surface dimer, twists 90° to break a pi bond, and then pulls to cleave the remaining sigma bond.
The whole concept of advanced nanotechnology — molecular manufacturing (MM) — is so complex and unfamiliar, and so staggering in its implications, that a few scientists, engineers, and other pundits have flatly declared it to be impossible. The debate is further confused by science-fictional hype and media misconceptions.
It should be noted that none of those who dismiss MM are experts in the field. They may work in chemistry, biotechnology, or other nanoscale sciences or technologies, but are not sufficiently familiar with MM theory to critique it meaningfully.
Many of the objections, including those of the late Richard Smalley, do not address the actual published proposals for MM. The rest are unfounded and incorrect assertions, contradicted by detailed calculations based on the relevant physical laws.
Nanotechnology offers great potential for benefit to humankind, and also brings severe dangers. While it is appropriate to examine carefully the risks and possible toxicity of nanoparticles and other products of nanoscale technology, the greatest hazards are posed by malicious or unwise use of molecular manufacturing. CRN’s focus is on designing and promoting mechanisms for safe development and effective administration of MM.
Viewed with pessimism, molecular manufacturing could appear far too risky to be allowed to develop to anywhere near its full potential. However, a naive approach to limiting R&D, such as relinquishment, is flawed for at least two reasons. First, it will almost certainly be impossible to prevent the development of MM somewhere in the world. China, Japan, and other Asian nations have thriving nanotechnology programs, and the rapid advance of enabling technologies such as biotechnology, MEMS, and scanning-probe microscopy ensures that R&D efforts will be far easier in the near future than they are today. Second, MM will provide benefits that are simply too good to pass up, including environmental repair; clean, cheap, and efficient manufacturing; medical breakthroughs; immensely powerful computers; and easier access to space.
The dangers of self-replicating nanobots — the so-called grey goo — have been widely discussed, and it is generally perceived that molecular manufacturing is uncomfortably close to grey goo. However, the proposed production system that CRN supports does not involve free-floating assemblers or nanobots, but much larger factories with all the nanoscale machinery fastened down and inert without external control. As far as we know, a self-replicating mechanochemical nanobot is not excluded by the laws of physics, but such a thing would be extremely difficult to design and build even with a full molecular manufacturing capability. Fiction like Michael Crichton’s Prey might be good entertainment, but it’s not very good science.
Based on our studies, CRN believes that molecular manufacturing could be successfully developed within the next ten years, and almost certainly will be developed within twenty years. For more, see our Timeline page.
We should do both! Development and application of molecular manufacturing clearly can have a positive impact on solving many of today’s most urgent problems. But it’s equally clear than MM can exacerbate many of society’s ills. Knowing that it may be developed within the next decade or two (which is not “far future”), makes preparation for MM an urgent priority.