Eli5: What makes things “sticky” like tape or any kind of adhesive? How do they stick on to smooth surfaces instead of coming off?
In: Chemistry
There’s a few things going on here at once.
1. Smooth surfaces aren’t actually “smooth” the tapes’ adhesive adheres to the tape because the tape has a rough side and a smooth side. The adhesive can’t come off the tape but will peel off “smooth” surfaces. Such as itself when unrolled
2. Smooth surfaces aren’t actually smooth. Microscopically the surface is just rough but on a smaller scale. Even glass is not smooth when looked at closely. Your adhesive is actually sticking by a force called cohesion to the microscopic cracks on a surface, you just can’t see it. When ripped off the cohesion force peels off the surface but only because the same forces of cohesion are stronger in the sticky adhesive bonds at the molecular lever.
Tape is stronger than the surface it’s stuck on. Its sticking to microscopic cracks that the adhesive fills in, making the adhesive surface area far greater than you can see. So it’s a combination of surface area with cohesion forces and the tape being stronger than the adhesion to the surface it’s applied.
Regarding surface area. Ever thought why glue works ? Its just non peelable tape with strong cohesion and more surface area contact because it’s wet when applied. PVA glue dried, then peeled off your skin is a fun experiment regarding what’s being said. 😛
Latest Answers