Growth of a cup-stacked carbon nanotube carpet with a superhydrophobic surface

A carpet structure composed of high purity cup-stacked carbon nanotubes (CSCNTs) was synthesized by a catalytic chemical vapor deposition method. In a 15-min growth time, the CSCNT carpet with a height up to ∼300 μm and carbon purity above 99.9 wt% was prepared. Transmission electron microscopy observations indicated that the CSCNTs with diameters ranging from 80 nm to 230 nm consist of truncated conical graphene layers. Based on the experimental results, a possible “base growth” mechanism was proposed for the CSCNTs. The CSCNT carpet is highly flexible and superhydrophobic, showing a contact angle of ∼155o. It can be easily harvested from the original growth substrate and be transferred to target substrates. It may therefore find applications as a water-proof and self-cleaning coating layer.