This question popped up in my mind when I was going through the explanations of coffee ring effect. Almost all of the explanations state that “the outer rim of the drop evaporates faster”, but unfortunately I couldn’t find any explanation WHY it dries faster than the inner part. Is it something to do with height? area? surface tension being stronger/weaker on the edge? temperature?
Edit:
Sorry for not adding any image, but what I actually meant was this:
[uneven evaporation of drop](https://www.ds.mpg.de/3208834/original-1559025408.jpg?t=eyJ3aWR0aCI6ODAwLCJoZWlnaHQiOjYwMCwib2JqX2lkIjozMjA4ODM0fQ==–01a65b684acafba312604a11b22490739a711d36)
As you can see from the image, the arrows indicating the magnitude of evaporation are stronger on the edges in 2D cross section. I was wondering why it is stronger there, rather than being even on crest and on the flanks of the drop
In: Chemistry
The inner portion has water molecules all around him to keep him insulated.
The portions on the outside edges would have half of their body exposed to the outside temperature.
It’s like if you were chilling on your living room couch as opposed to chilling at your front door with it open and half of your body sticking outside of the door. The outside temperature would affect you more.
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