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While using a topical lotion based on ethanol, water and propylene glycol, I noticed that it becomes sticky while drying. Propylene glycol is a humectant and is used for this purpose in pharmaceuticals and cosmetics. This made me wonder: Is stickiness a general property of all humectants?

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    $\begingroup$ Hmm, humectants share 2 essential properties: 1/high hydrophilicity 2/ low volatility // Both can be achieved e.g. by many hydrophilic groups like OH ( glycols, glycerol, polyvinylalcohol PVA). Not sure if PVA is sticky as well, but I would guess it may be. // It is quite possible stickiness and water retention are 2 aspects of the same quality here.// What may play role is the type of emultion ( oil in water or water in oil ) $\endgroup$
    – Poutnik
    Commented Aug 11, 2022 at 7:17

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