Fundamentals of Adhesion

So why does the wax behave differently than the paint in terms of preventing the water to “wet out”? The answer is due to an intrinsic property of every material called surface energy, which is measured by the strength of bonding energies at the surface of any material. A simplified explanation of surface energy is that “unhappy” molecules at the surface do not have a full complement of molecules around them to balance out their attractive forces. These surface molecules therefore exhibit increased adhesive affinity to different molecules that touch the surface. Surface energy can be directly measured for every substance as a function of force per unit length.