When you write with permanent marker it’s meant to be permanent, *obviously.* It doesn’t usually rub off of most surfaces, especially whiteboards. But if you write on a whiteboard with permanent marker, and then write over it with whiteboard marker, you can rub off parts the second marker touched. Why is this?
In: Chemistry
Marker ink is composed of a pigment dissolved in a volatile solvent. When you write with one, it goes on wet, then as the solvent evaporates, it leaves the pigment behind.
White board and permanent markers use the same solvents, the difference is in the pigment. Permanent markers have much smaller particles which bind to surfaces much more securely than white board markers, which have large and flaky particles.
When you write over permanent marker with a dry erase marker, the permanent pigment dissolves in the solvent and can be wiped away
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