Post-it notes are a classic application of polymer chemistry. Funnily enough, the stickiness in question was discovered when Spencer Silver was trying to produce an incredibly strong adhesive in 1968. Instead, he produced an incredibly weak one, but most discoveries are accidents, so who is going to complain? Perhaps just students like myself as we stick up reminders of our exam dates and assignments. The glue used in Post-it notes is a pressure-sensitive adhesive. This means you only need to apply light pressure to stick the note to something. The bond between the note and the surface is formed through a fine balance between flow and resistance to it. The adhesive can flow just enough to fill tiny crevices on the surface, but will resist flow enough to remain there. This produces the bond between the note and the surface.
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