How does a sharpie evaporate?

Answer 1

What happens when the cap is left off a "magic marker" is that the solvent or "carrier fluid" for the pigment (both of which comprise the ink) vaporizes and "goes away" leaving the marker dry and unusable. It should be noted that the ink in the marker is composed of two main parts: pigment and a carrier. The carrier is used to make the pigment "flow" onto the surface being marked, and then it goes away. If the cap is not put on tightly, the carrier doesn't know it isn't time to go away and it does, and this leaves the marker dry and ineffective. The liquid part of the ink containes toluene or xylene (or a combination of the two), both of which are highly volatile. There is also a flock of other things in there (in small quantities) to optimize the performance of the ink and help deposit the pigment or dye more effectively. Trying to "revive" the pen isn't worth the effort, because making a mixturte of the chemicals is difficult, expensive, and dangerous. It is more cost effective to replace the marker - and replace the cap when you're finished using it so it won't go the way of the first marker.

Answer 2

A Sharpie contains volatile solvents that evaporate over time when the cap is left off, causing the ink to dry out. This process is accelerated by exposure to air and heat, leading to evaporation of the liquid components and leaving behind the solid ink on surfaces.