The surface energy of a polymer plays a crucial role in determining its adhesion properties to different substrates. Surface energy is the excess energy at the surface of a material compared to the bulk material, and it is a measure of the strength of the intermolecular forces near the surface. In the context of adhesion, surface energy affects the wetting, spreading, and interfacial interactions between the polymer and the substrate.1. Wetting: Wetting is the ability of a liquid in this case, the polymer to maintain contact with a solid surface the substrate . The degree of wetting depends on the surface energies of both the polymer and the substrate. A higher surface energy polymer will have better wetting properties on a substrate with a similar or higher surface energy. This is because the attractive forces between the polymer and the substrate are stronger, leading to better contact and adhesion.2. Spreading: Spreading refers to the ability of a liquid the polymer to spread over a solid surface the substrate and is influenced by the surface energies of both materials. A polymer with a higher surface energy will tend to spread more easily on a substrate with a similar or higher surface energy, resulting in a larger contact area and better adhesion.3. Interfacial interactions: The strength of the adhesion between a polymer and a substrate is influenced by the interfacial interactions that occur at their boundary. These interactions can be physical e.g., van der Waals forces, hydrogen bonding or chemical e.g., covalent bonding, ionic bonding . A higher surface energy polymer will generally have stronger interfacial interactions with a substrate, leading to better adhesion.In summary, the surface energy of a polymer affects its adhesion properties to different substrates by influencing the wetting, spreading, and interfacial interactions between the two materials. A higher surface energy polymer will generally have better adhesion properties on substrates with similar or higher surface energies. To improve adhesion between a polymer and a substrate, one can modify the surface energy of either material e.g., through surface treatments, adding adhesion promoters, or changing the polymer formulation to enhance their compatibility and promote stronger interfacial interactions.