Diffusion slowdown blockade
When going to larger sizes one faces:
- much lower speeds – typically much below the speed of sound
- much larger distances
- => much much lower random part encounter rates
The encounter rate of small molecule sized parts at the nanoscale due to thermal motion is mindbogglingly high.
To get an intuitive feel about just how much macroscale is at a disadvantage see page: The speed of atoms
This obstacle can be hit when scaling termination control and site addressability in
technologies that use thermally driven self-assembly to rather large scales.
Like e.g. already the casein the higher selfassembly levels of structural DNA nanotechnology.
Why not keep adding small parts to big parts?
One can not just keep small fast diffusing parts to increasingly bigger (and non moving) products as
the addressing space on the surface gets too big eventually.
At last not with additional tricks as one way around the diffusion slowdown blockade.
Delineation to slowdown from finding sparse binding partners
This can lead to severe slowdown.
But this can be easier fixed by switching to other strategies
like going from more self finding to more self folding type of thermally driven self assembly.
- more concretely: templating strands in structural DNA nanotechnology
- more abstractly: increasing effective concentration
The issue is that even with that optimized to the maximum
the diffusion speed blockade still remains.
Related
External links
(wiki-TODO: Add links to videos of macroscale demos of selfassembly of 3D printed virus-shell models with magnets inside.)