A Perfectly Hydrophobic Surface (θA/θR = 180°/180°)

A perfectly hydrophobic surface with both advancing and receding water contact angles of 180° was prepared using a facile method on a silicon wafer. Phase separation of a toluene-swollen covalently attached methylsilicone results in a nanoscale network structure that is responsible for the superhydrophobicity. A method for testing extreme hydrophobicity was devised to distinguish between surfaces exhibiting contact angles of 180 and 179°.