The modifications of the surface wettability of amorphous carbon films

Stable and easily controllable wettability of a solid surface is of great significance in many applications. In the present studies, a-C films with special nano-structured surfaces were deposited on silicon and glass substrates with magnetron sputtering method. The morphologies of the surfaces vary with the deposition parameters. Therefore, these a-C surfaces can be controlled to exhibit different wettability in a wide range from the hydrophilicity to the super-hydrophobicity. The studies also prove that the CF4 plasma treatment will remarkably enhance the hydrophobicity of the a-C films. And the fluorinated a-C surfaces show an excellent super-hydrophobic property for all the pH values of the aqueous solution. Moreover, a super-hydrophobic surface of the non-fluorinated a-C film can be reversed to being very hydrophilic by the plasma treatment of H2 or N2, while the fluorinated super-hydrophobic a-C films show a good stability.