[X] My Assistant

[ngunn]

From 'Science Daily':

http://www.sciencedaily.com/releases/2009/...90825163726.htm

[marsbug]

Why are free bases in general more sticky than the salt forms? Speculating wildly, it could be that the free base amines form relatively weak transient H-bond interactions between the molecules in the solid network. These sloppy intramolecular bonds make the intramolecular arrangments less ordered. But protonate them up under acidic conditions, and you force a local cationic charge that can set up a more defined and orderly network of cation-counterion <and solvent> couples. A more ordered network makes a more solid matrix.

But that's about the limit of my knowledge of atomic-level surface science....

Thats well above my level of organic chemistry! But from working on putting down nitride and oxide coatings there will very likely be an intermediate layer between any two grains. In fact it's bloody hard to get rid of, even under high vacuum conditions most things have a layer of oxides that need ion etching off. Depending on the exact conditions on earth it's almost always water plus greater or lesser amounts of what else is in the atmosphere. From there a lot depends on how the surface reacts with water and the atmospheric gasses, so as a total shot in the dark I'd suggest that the free bases have a better affinity for atmospheric water, or more likely something they make as a layer on reacting with air ( oxygen content a likely suspect?) has a better affinity. On titan the grains would (I imagine) be most likely to condense monolayers of simple organics to start with. More wild speculation: Is there any chance polymers could form and each grain could have a tangle of polymers around it, acting like very tiny velcro?