There's a bit of stuff like that in carbohydrate chemistry: polysaccharides that gel depending on temperature or pH changes, or on dilution - one of the reasons why we were doing molecular modelling/dynamics studies on carrageenans, for example, back in the early nineties.
But yeah, cyclodextrins are weird even by carbohydrate chemistry standards: I spent the first six months of my PhD looking at cyclodextrins as artificial enzymes (the idea had been to modify the hydroxyl groups around the primary face to carry functionality that could be used to react with guest molecules trapped in the hydrophobic cavity), and we could track changes in the hydrogen-bonding patterns by nmr.
Or you could take a litre of fairly strong cyclodextrin solution, and a litre of similarly concentrated straight-chain amylose oligomer and pour a couple of moles of benzene (or toluene or other hydrophobic aromatic)) into each, and with a little warming and shaking, the aromatic layer would dissolve into the cyclodextrin solution but not the other one.
Bloody hell -- that is quite cunning stuff. Very freaky. I admit I had thought that impossible -- neglected the possibility of two substances bonding with each other.
I can offer a far simpler answer to her conundrum.
This stuff is fine until lightly heated by a large scale four flame Bunsen (a standard gas hob will do.) At which point it forms a gel-like solid which resists all attempts to return it to its liquid state.
I speak of the solution Devalmont's HydroxyBistocene.
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Date: 2004-09-26 02:18 am (UTC)But yeah, cyclodextrins are weird even by carbohydrate chemistry standards: I spent the first six months of my PhD looking at cyclodextrins as artificial enzymes (the idea had been to modify the hydroxyl groups around the primary face to carry functionality that could be used to react with guest molecules trapped in the hydrophobic cavity), and we could track changes in the hydrogen-bonding patterns by nmr.
Or you could take a litre of fairly strong cyclodextrin solution, and a litre of similarly concentrated straight-chain amylose oligomer and pour a couple of moles of benzene (or toluene or other hydrophobic aromatic)) into each, and with a little warming and shaking, the aromatic layer would dissolve into the cyclodextrin solution but not the other one.
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Date: 2004-09-26 02:26 am (UTC)no subject
Date: 2004-09-26 02:47 am (UTC)no subject
Date: 2004-09-26 02:55 am (UTC)no subject
Date: 2004-09-26 04:32 am (UTC)My grip on relaity :)
Fascinating!
Date: 2004-09-26 09:11 am (UTC)Re: Fascinating!
Date: 2004-09-26 09:17 am (UTC)no subject
Date: 2004-09-26 10:51 am (UTC)This stuff is fine until lightly heated by a large scale four flame Bunsen (a standard gas hob will do.) At which point it forms a gel-like solid which resists all attempts to return it to its liquid state.
I speak of the solution Devalmont's HydroxyBistocene.
Also known as My Gravy.
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Date: 2004-09-27 01:24 am (UTC)The stuff they use in hand warmers.
Not quite the same I know but still an interesting property.
http://thermo-pad.com/how.htm
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Date: 2004-09-27 04:20 am (UTC)seth
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Date: 2004-10-02 08:12 am (UTC)