Reversible wettability on polycrystalline diamond films between superhydrophobicity and superhydrophilicity.

Reversible wettability on the polycrystalline diamond film was investigated through the alternation of hydrogen and oxygen plasma treatment. This can be ascribed to the reversible switching of the surface terminal chemical properties between two different states. The water contact angle could be varied between 5.9 degrees and 88.9 degrees when the diamond film was prepared on a flat substrate. When diamond films with multi-scaled roughness were fabricated, the wettability conversion could be amplified, leading to switching between superhydrophobicity and superhydrophilicity.