Design of an outstanding super-hydrophobic surface by electro-spinning

A duel-layer super-hydrophobic surface, comprising polyvinylidene fluoride (PVDF) and fluorinated silane molecules (FSM), was engineered using electro-spinning a coating onto the glass. Scanning electron microscopy was used to confirm that, by reducing the percentage of PVDF in the spraying solution, the aspect ratio of the nano-beads could be changed and a sharp bead profile obtained. Energy dispersive spectroscopy was employed to ensure the maximum amount of FSM was present on the surface, which assists in achieving a high Water Contact Angle. Using a two-step process, involving PVDF and FSM, nano-beads, with high aspect ratio, were formed on a rough surface which produced a super-hydrophobic surface with a Water Contact Angle of 170.2 degrees and a very low Water Roll-off Angle (<1 degrees). Such a coating facilitates the speedy run-off of water drops from a surface and has many potential applications in buildings and other areas. (C) 2011 Elsevier B.V. All rights reserved.