Actually this is going to be a list of interconnected questions. Please bear with me.
Wikipedia article on cyclodextrin (CD) says that it is hydrophobic from inside.
(1) How is it hydrophobic when there are so many hydroxyl groups on the interior surface ?
(2) This image labels the interir cavity as apolar rather than hydrophobic. I guess the apolarity is because of mutual cancellation of the dipole moments. Am I right on this?
In any case I don't understand how the cavity excludes water.
(3) How does this trapping exactly occur ?
(4) Do the hydroxyls play a role in restricting the diffusion of the trapped organic molecules out of the cavity ?
All of this, I started investigating because of a recent news about an alcoholic beverage in powder form- palcohol. Initially I didn't believe it but later I found that alcohol is absorbed in CD to make a dry powder.
(5) What prevents alcohol from adsorbing on the exterior surface and not make the powder sticky ?
(6) Other studies say that there is a 1:1 ratio of trapping but palcohol claims that it is 58% alcohol by weight. Even this old patent says that CD absorbs a lot of alcohol. How does that happen ? In all it seems that CD behaves differently with different molecules.