Adhesion is the tendency of certain dissimilar molecules to cling together due to attractive forces. In contrast, cohesion takes place between similar molecules. Mechanisms of adhesion Five mechanisms of adhesion have been proposed to explain why one material sticks to another: Mechanical adhesion Adhesive materials fill the voids or pores of the surfaces and hold surfaces together by interlocking. Sewing forms a large scale mechanical bond, velcro forms one on a medium scale, and some textile… (More on Adhesion)