Long-lasting Hydrophilicity on Nanostructured Si-incorporated Diamond-like Carbon Films

Jin Woo Yi, Myoung-Woon Moon, Sk. Faruque Ahmed, Haeri Kim, Tae-Gon Cha, Ho-Young Kim, Seock-Sam Kim and Kwang-Ryeol Lee

The long-lasting hydrophilic behavior of a Si-incorporated diamond-like carbon (Si-DLC) film was investigated by varying the Si fraction in DLC matrix through oxygen and nitrogen plasma surface treatments. The wetting behavior of the water droplets on the pure DLC and Si-DLC with the nitrogen or oxygen plasma treatment revealed that the Si element in the oxygen plasma treated Si-DLC films played a major role in maintaining a hydrophilic wetting angle less than 10° for 20 days in ambient air. The nanostructured patterns with a roughness about 10 nm evolved due to the selective etching of the carbon matrix by the oxygen plasma in the Si-DLC film, where the chemical component of the Si-Ox bond was enriched on the top of the nano-patterns and remained for over 20 days.