Near-superhydrophobic behavior of multi-walled carbon nanotube thin films

Thin films of multi-walled carbon nanotubes created by standard drop and dry methodology are reported here to give water contact angles of ~ 138° accessing an intermediate region between smooth, apolar materials and superhydrophobic surfaces. Their near-superhydrophobic nature is attributed to hierarchical nanoscale roughness leading to the formation of Cassie–Baxter interfaces. While complete quantitative determination of surface energy parameters was prevented due to the porous nature of the films, the dispersive component of nanotube surface energy was found to be in the range of 39.1–47.8 mJ/m2.

► Multi-walled carbon nanotube films show near-superhydrophobic behavior.
► Hierarchical nanoscale roughness of nanotube film leads to Cassie–Baxter interface.
► Carbon nanotubes possess dispersive surface energy component between 39.1 and 47.8 mJ/m2.