Superhydrophobic Carbon Nanotube Forests

Abstract

The present study demonstrates the creation of a stable, superhydrophobic surface using the nanoscale roughness inherent in a vertically aligned carbon nanotube forest together with a thin, conformal hydrophobic poly(tetrafluoroethylene) (PTFE) coating on the surface of the nanotubes. Superhydrophobicity is achieved down to the microscopic level where essentially spherical, micrometer-sized water droplets can be suspended on top of the nanotube forest. Since their discovery in 1991,1 carbon nanotubes continue to be a subject of unabated scientific research and develop-ment. Their extraordinary properties2-4 make them highly attractive as technology enablers in a host of different applications, ranging from fillers in polymer nanocomposites to conductors in molecular electronics.5 Carbon nanotubes can be single-walled (SWNTs) or multiwalled (MWNTs), metallic or semiconducting, and isolated or attached to a substrate. The ability to grow nanotubes directly on a substrate using various chemical vapor deposition techniques