A surface modification procedure based on the cold plasma technique has been utilized in order to introduce new functional groups onto muscovite mica surfaces. In the first reaction step mica surfaces are exposed to a water vapor plasma. The interaction between mica surfaces and reactive species in the plasma results in information of surface hydroxyl groups. These groups are reactive toward chlorosilanes in the gas phase, which provides a versatile way to obtain mica surfaces with a variety of different surface chemical groups. For instance, poly(ethylene oxide) chains have been covalently attached to mica surfaces.-In a different surface modification route, mica surfaces have been coated with thin plasma polymer layers. Mechanical and surface properties of plasma polymer films depend, of course, on the type of monomer, but also on the condition used during polymerization (e.g., flow rate, pressure and discharge power). The surface force technique has, together with spectroscopic analyses, provided information about how the adhesion force and mechanical strength of different plasma polymers of acrylic acid depend on the polymer structure.