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Nanotechnology

...using catenanes, rotaxanes and more

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APPLICATIONS OF THIS TECHNOLOGY


Molecular switches


Rotaxanes, as discussed earlier, can act as molecular switches, changing position depending on different factors. Thus specially designed rotaxanes can respond to different environments such as oxidation, reduction, light and pH. Some rotaxanes respond better to different environments eg. Azobenzene based rotaxanes respond well to light, and others can respond to many different influences.
ant
(above) An ant carrying a tiny computer chip!
Ref 4a
Computers in their most basic form are simply lots of switches, or "logic gates", thus potentially, rotaxanes could be used as molecular computers. The advantage of this would be that unlike silicon based computers, the size vs the number of switches would be much better. In fact, it has been suggested that these machines could work 100 billion times faster! They would also use much less power.
In other fields of nanotechnology, carbon nanotubes have been used to carry current and act a molecular wires. DNA has also been suggested as the base for a "biological" computer, and "quantum" computers have also been suggested.





molecular mechanics


propellor
(above) A propellor.
Ref 4b
Using other "mechanically linked" molecules, structures that mimic things such as propellors, pistons and even gears are a possibility. Although we are a long way off from tiny nanomachines, it is does now seem theoretically possible.
Rotors made so far tend to use bulky aromatic groups extended from a central atom, which are able to spin, the alignment of these molecules creates a structure similar to that of a propellor. Gears can be made by using these large, typically flat structures to link with each other, however they much be carefully spaced.
These could, potentially be activated using electron flow, in a similar fashion to rotaxane switches. However, some structures have been made that use catenanes as a "brake", that in the presences of eg a Cu+ ion, join together and stop the mechanism.
Although these structures are still in their infancy, structures have been made using carbon nanotubes that mimic pistons, and also gears, and potentially biological rotors such as ATPase could aslo be utilised.

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