Almost each and every surface open to the elements existing in the ordinary atmosphere goes through water and gas absorption within the molecular bounds. Oxidation processes can also bring about a change in surface conditions. Since exposure leads to the gathering of contaminants on a surface, it is imperative that the surface be treated prior to any kind of adhesion.
The quality of adhesion on a surface depends on the amount of surface energy a material possesses. If the surface energy is low, then the adhesion of coatings or inks is most likely to be unsuccessful. Coating, printing, painting etc. can be done on almost all kinds of surfaces.
But some materials require surface treatment or pretreatment before any actual coating takes place. Surface treatment modifies the surface of a material making it more adherent to the changes that are about to take place. Therefore, solving the adhesion problem becomes quite crucial.
Surface modification is carried out mostly on materials that are too expensive or sensitive for chemical or mechanical treatments. For example, wet chemical techniques create a lot of hassle when it comes to the treatment of surfaces. As many solutions and acids are used in this process to remove the foreign contaminants residing on the surface, the process ends with chemical residue covering the surface.
Hence, another round of cleaning is to be initiated for removing the residue of chemicals that were set to clean that surface in the first place. Other methods or pretreatment include pickling and sandblasting etc. which leave the surfaces more damaged than clean..