How can chemical reactions at a surface create an adhesive bond?

Chemical reactions at a surface create an adhesive bond through a mechanism known as adsorption and surface reaction. In this process, adhesive molecules adsorb onto a solid surface and undergo a chemical reaction with it, forming a bond that is distinct from simple physical adsorption.1

While some researchers categorize this as part of a broader adsorption process, it is often distinguished because the chemical interaction creates specific, strong bonds between the adhesive and the adherend. This mechanism is one of several ways adhesion is achieved, alongside others such as mechanical interlocking, interdiffusion, and electrostatic attraction.1

For an adhesive bond to form effectively, the adhesive must first wet and spread across the surface to ensure intimate molecular contact. In many synthetic adhesives, such as epoxy resins, this bond formation can occur simultaneously with a curing step, where polymerization takes place to solidify the joint. The resulting interphase—a transitional zone between the adhesive and the surface—is critical, as its composition largely determines the strength and durability of the bond.12