The process of functionalization involves the reaction of plasma generated radicals with the sample surface resulting in the addition of specific chemical functionality to the material surface. For example, amino (NH2) functionality can be added to the surface by utilizing ammonia as a plasma process gas. Other chemistries can yield oxides, hydroxides, and carboxyl groups. Functionalizing the surface with plasma is a common technology used to improve bonding between incompatible materials. It helps facilitate strong chemical bonds between the adhesive and the bonding materials. Functionalization can also allow for the attachment of an anti-coagulant such as heparin and anti-viral or anti-microbial molecules to surfaces. Contact lens treatment is a common functionalization application where the lens surface is oxidized to create a hydrophilic lens surface that is resistant to protein deposition.