Chemistry of pressure-sensitive adhesives

Let's imagine you have a piece of tape that you use to stick things together. The glue on the tape is called a pressure-sensitive adhesive (PSA).

Now, PSA is like a really sticky bubble gum. When you want to stick two things together, you need to apply a little bit of pressure, like chewing the bubble gum, to make it stick. The more pressure you apply, the stickier the PSA becomes.

The chemistry of PSA is very interesting because it is a mix of different materials. Some of these materials include polymers that make the PSA stretchy and sticky, and tackifiers that make it stickier than bubble gum.

When you press the tape onto a surface, the sticky molecules on the tape's surface stick to the surface's molecules. This creates an attractive force between the two surfaces, just like a magnet. This force keeps the tape and the surface together.

The molecules in the PSA are also flexible enough to bend and twist, allowing the tape to conform to different surfaces like a curved edge or a bumpy surface. This is why you can use tape to stick things together, even if they are not perfectly flat.

In summary, PSA is a special kind of glue that becomes stickier when pressure is applied. It is made of different materials that make it stretchy and flexible, allowing it to stick to different surfaces. The chemistry behind PSA is fascinating and important for making everyday items like tape and sticky notes.