[HealthTeacher (OP)]

Once pealed from the note pad, how long will sticky notes stay sticky?  What causes them to loose their "stickyness" if they do?

[evan_au]

They can stay sticky in the pad for years.

Once peeled from the pad, they stick to all sorts of dirt, dust and skin oils.
Only a small area of glue remains exposed - and that can't make good contact because of the thickness of dust and hairs etc that is already coating the sticky surface.

[ohlala]

It depends on the environment the sticky note is in once it's been peeled from the pad. If there's a lot of dust then it won't stay sticky for long. The more you stick and un-stick it from surfaces, the less sticky they will become eventually

[HealthTeacher (OP)]

Over time would the adhesive ever dry out.......releasing all the "stuff" stuck to it?  I know many things as mentioned stick to the sticky notes, but does the sticky note leave anything behind when it is stuck to things?  Ex. desk, wall

[chris]

What actually is the adhesive used on post-it notes that has those quite special characteristics of being peelable and not too sticky?

[evan_au]

What actually is the adhesive used on post-it notes

This has often been quoted as a discovery that "failed" in its intended application as an adhesive, but eventually created a niche of its own...