Initial Nanotech Base
From Wise Nano
The base material initially utilized will have strong effects on nanotechnology's development, what it'll be able to do - and what it won't. Below is a list of commonly discussed substrates.
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Carbon
(temperature stability versus heat load, biocompatibility of fragments, crystalline fracture planes, etc)
The most common material usually mentioned in regards to nanotechnology is carbon. Carbon can produce diamond, graphite, and buckminsterfullerine (in the form of spheres, onions, tubes, horns, rolls...), each of which have some incredibly useful structual properties (high hardness for diamond, 'doped' diamond capable of becoming transistors, very high tensile strength for buckminsterfullerine tubes, with excellent lubrication properties for graphite and buckminsterfullerine spheres, among others).
There is some question regarding carbon materials' flammability - perhaps even fuel-air explosive (FAE) or grain-elevator type explosive flammability. However, building small water tanks into a carbon structure would greatly reduce flammability, first by increasing thermal mass, then by evaporative cooling if the thing ever gets that hot. Small water tanks may be useful for another reason: a pressurized tank is a very material-efficient structural member.
The extremely high thermal conductivity of diamond can be very useful for some applications, but may have drawbacks as well. Some buckytubes may have very low thermal conductivity due to defects reflecting the phonons sideways. Alumina may be a good alternative thermal barrier.
It is also important to figure out how to eliminate diamond waste. It is as non-biodegradable as a substance gets. It seems to be more or less biocompatible. Surfaces with nanoscale features may react differently than those with mere micro-scaled features. But chemical vapor deposition (CVD) diamond is what biocompatibility has been tested on, and its features are small and random. Fullerenes may also be a concern; preliminary experiments have shown that their toxicity depends heavily (orders of magnitude) on their surface coating.
Silicon
(lack of structual capacity, etc) Silicon Nanotechnology, from Intel.
Alumina (sapphire)
A ceramic, alumina is completely non-flammable. It is somewhat weaker than diamond. It conducts a lot less heat at room temperature, though interestingly its heat conductivity rises near liquid nitrogen temperatures. (See Vasculoid paper).
Iron
(oxidation concerns, inductance/magnetic concerns, etc)
Iron appears to be more relevant to regarding nanomaterials than nanomachines. Any references regarding iron nanomachines would be welcome.
Biopolymers (DNA and protein)
DNA as a construction material, from the 5th Foresight conference.
(other - carborundumoid? TiC?)
Any pointers would be highly appreciated.
