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

Abstract

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 ° can be achieved. The interfacial phenomenon between the water droplet and the solid surface is also analyzed by the Cassie-Baxter models.