Influence of fluorine/carbon atomic ratio on superhydrophobic behavior of carbon nanofiber arrays

The present study has demonstrated the influence of the fluorine/carbon (F/C) ratio on superhydrophobicity of carbon nanofibers (CNFs) prepared by a template-assisted synthesis. An approach to coat fluorocarbon on the surface of nanofibers is introduced via a thermal chemical vapor method, using perfluorohexane as the precursor. The resulting CNFs exhibit good water-repellent behavior owing to hydrophobic surface groups including -CF2 and -CF3 groups. Experiments indicate that the F/C atomic ratio is the key factor for obtaining the hydrophobic properties. The surface contact angle increases with increasing F/C ratio. Contact angles of the fluorinated CNFs as high as 161 degrees can be achieved. The interfacial phenomenon between the water droplet and the solid surface is also analyzed by the Cassie-Baxter models. (c) 2006 American Vacuum Society.