Cohesive and Adhesive Liquids

Cohesion and adhesion are the result of attractive intermolecular forces acting between either two adjacent parts of the same substance (cohesion), or two different substances (adhesion), typically involving solids or liquids. These forces primarily arise because of electrical interactions between molecules. When molecules are very close, they repel each other, while at greater distances, they attract. At an optimal intermediate distance, the potential energy between them is minimized, and work is required to either bring them closer or pull them apart. Consequently, work is necessary to separate two objects in close contact, whether they are composed of the same or different materials.