CO2 laser treatment for stabilization of the superhydrophobicity of carbon nanotube surfaces

In this work, the authors demonstrate the formation of stable superhydrophobic vertically aligned multiwalled carbon nanotube (VACNT) surfaces through CO2 laser irradiance, in which the contact angle value reached 161 degrees. VACNT arrays were synthesized by microwave plasma chemical vapor deposition using N-2/H-2/CH4 [10/90/14 SCCM (SCCM denotes cubic centimeter per minute at STP)]. CO2 laser technique was applied on VACNT surfaces with irradiance at different laser powers to promote the great stability of superhydrophobic surfaces. Contact angle measurement reveals that irradiated VACNT surface is superhydrophobic at all irradiances tested. Unlike as-grown VACNT, the samples treated with CO2 laser show no sign of water seepage even after a prolonged period of time (similar to 24 h). This characteristic is very interesting and has various possible functional applications in micro- and nanomaterials and devices. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3502024]