Surface modification of polymers is a process that involves altering the surface properties of a polymer material to improve its adhesion properties with other materials. This can be achieved through various techniques such as chemical treatments, plasma treatments, or physical methods like abrasion or etching. The modification can result in changes to the surface chemistry, topography, and energy, which in turn affect the adhesion properties of the polymer.There are several underlying chemical factors responsible for the change in adhesion properties after surface modification:1. Surface chemistry: Surface modification can introduce new functional groups or alter the existing ones on the polymer surface. These functional groups can interact with the other material through various bonding mechanisms such as hydrogen bonding, van der Waals forces, or covalent bonding. The presence of these new functional groups can enhance the compatibility and adhesion between the polymer and the other material.2. Surface energy: Surface modification can change the surface energy of the polymer, which is a measure of the thermodynamic state of the surface. A higher surface energy indicates a more reactive surface, which can improve the wetting and adhesion properties of the polymer with other materials. This is because a higher surface energy promotes better spreading of the adhesive or other material on the polymer surface, leading to a larger contact area and stronger adhesion.3. Surface topography: Surface modification can also change the surface topography of the polymer by creating roughness or patterns on the surface. This can increase the mechanical interlocking between the polymer and the other material, leading to improved adhesion. The increased surface area due to roughness can also enhance the chemical interactions between the polymer and the other material, further improving adhesion.4. Crosslinking: Some surface modification techniques, such as plasma treatment or UV irradiation, can induce crosslinking on the polymer surface. Crosslinking can increase the rigidity and stability of the polymer surface, which can improve its adhesion properties with other materials. Additionally, crosslinked surfaces can have higher surface energies, which can further enhance adhesion.5. Removal of surface contaminants: Surface modification can remove contaminants such as oils, dust, or low molecular weight species from the polymer surface. These contaminants can act as barriers to adhesion, so their removal can improve the adhesion properties of the polymer with other materials.In summary, surface modification of polymers can affect their adhesion properties with other materials by altering the surface chemistry, energy, topography, and crosslinking. These changes can lead to improved compatibility, wetting, and mechanical interlocking between the polymer and the other material, resulting in stronger adhesion.