I have yet to see an example of a molecule that's both polar and hydrophobic or that's both non-polar an hydrophilic. If no such molecule exists, why use the terms "hydrophilic" and "hydrophobic" at all if we can just refer to them as being polar or non-polar? If there are such molecules, what are some examples and why do they exhibit non-polarity and hydrophilicty, or polarity and hydrophobicity?


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Hydrophilicity/hydrophobicity/lipophilicity/lipophobicity and polarity/non-polarity are terms that overlap to a great extent in simple substances, but which are not strictly equal. The former terms can have a much more involved explanation depending on several factors, even if polarity is usually the largest by far.

Philicity and phobicity are determined by contact angles between substances. It is possible to vary how a same substance gets wetted by exploiting surface patterning, which fiddles with the surface tension between the substances in contact.

Another interesting example I can think of is that some large perfluorocarbons are non-polar, but they are also lipophobic. It is possible to mix water, oil and a perfluorinated solvent, shake, and then watch as three clearly distinct phases separate.

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    $\begingroup$ So if I understand you right, a molecule's polarity can be a contributing explanation for its observed hydrophobicity, but saying the reverse (hydrophobicity explaining polarity) wouldn't make much sense. I'll have to check out those wikipedia pages as well. $\endgroup$
    – Tyler
    Commented Nov 30, 2013 at 22:55

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