Structural properties and surface wettability of Cu-containing diamond-like carbon films prepared by a hybrid linear ion beam deposition technique

• Cu-containing diamond-like carbon (DLC) films were deposited by a hybrid ion beam system.
• Cu-containing DLC films exhibited a wide range of water contact angle.
• The water contact angles vary with the surface energies and surface roughness.

Cu-containing diamond-like carbon (Cu-DLC) films were deposited on Si/glass substrate by a hybrid ion beam deposition system. The Cu concentration (0.1–39.7 at.%) in the film was controlled by varying the sputtering current. The microstructure and composition of Cu-DLC films were investigated systematically. The surface topography, roughness and surface wettability of the films were also studied. Results indicated that with increasing the Cu concentration, the water contact angle of the films changed from 66.8° for pure carbon film to more than 104.4° for Cu-DLC films with Cu concentration larger than 24.4 at.%. In the hydrophilic region, the polar surface energy decreased from 30.54 mJ/m2 for pure carbon film to 2.48 mJ/m2 for the film with Cu 7.0 at.%.