Superhydrophobic Carbon Nanotube Forests Kenneth K. S. Lau (*,1), José Bico (2), Kenneth B. K. Teo (3), Manish Chhowalla (4), Gehan A. J. Amaratunga (3), William I. Milne (3), Gareth H. McKinley (2) and Karen K. Gleason (1) (1) Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. (2) Department of Mechanical Engineering, Massachusetts Institute of Technology,Cambridge, Massachusetts 02139, USA. (3) Engineering Department, University of Cambridge, Cambridge CB2 1PZ, United Kingdom. (4) Department of Ceramics and Materials Engineering, Rutgers University, Piscataway, New Jersey 08854, USA. (*) e-mail: klau@mit.edu Abstract: The present study demonstrates the creation of a stable, superhydrophobic surface using the nano-scale roughness inherent in a vertically aligned carbon nanotube forest together with a thin, conformal hydrophobic polytetrafluoroethylene (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.