Intercrystolecular forces
Contents
Van der Waals force / London dispersion forces
Hydrogen passivated crystolecules should stick together nicely and firmly due to the van der Waals force.
Omnidirectionally.
Stronger polar forces
But for other types of nanoscale passivations there are also partly polar interactions
that may be 10x stronger than these vdW forces. Both attractive and repulsive. Examples:
- Attractive: R-H~O=R & R-H~N≡R &
- Repulsive: R=O~O=R & R≡N~N≡R & R=O~N≡R
Similar for 3rd period elements.
Analogies from biological systems can only be drawn from the attractive case as in the repulsive case
the atoms can just turn away due to being anchored on a floppy free floating/swimming molecule.
And even for the attractive case attractive case there are significant differences as
dipoles usually don't come in a forced parallel array.
Dipoles are shorter range than (locally) lone standing charges.
A full nitroxy nanoscale passivation should act like a closed shell of dipoles
all facing normal to the crystolecules surface.
This may reduce the range of the forces even further.
Dative electron deficit bonds – Transition to covalent
Dative bonds aka electron deficit bonds can be very strongly attractive.
- Prototypical near covalent example: -R-N~B-R-
This is most certainly not suitable for sliding interfaces.
Bonds like these should be considered
– intracrystolecule forces rather than
– intercrystolecule forces.
Related: Boron nitrogen dative bond interfaces
Irrelevance of gravity
Note that gravity is many many orders of magnitude smaller that all these forces.
So attraction and repulsion balancing each other out exactly over a larger space such that gravity matters can't everhappen.
Nonlinearity of forces ensures that.
- Either crystolecules stick together like hell
- Or crystoleculed shoot apart like hell
- No gravity fall-off ever. (wiki-TODO: Calculate 1nm cube HUGE acceleration level needed for overpowering vdW force)
If for whatever reasons getting crystolecules into free space and slowing them down such that gravity can be observed acting on them is likely a nontrivial challenge. Well a single charged one in a large optical trap should be easy as we even do that wth elemental particles today (2014). Many neutral crystolecules floating in small nanoscale spaces, that should be hard.
