Adhesion

Adhesion is the molecular attraction exerted between bodies in contact. It is of particular interest to engineers who wish to stick objects together and to biologists to understand the workings of cells.
The strength of the adhesion between two materials depends on which of the above mechanisms occur between the two materials, and the surface area over which the two materials contact. Materials that wet against each other tend to have a larger contact area than those that don't. Wetting depends on the surface energy of the materials.