Manufacturing and characterisation of water repellent surfaces

The leaves of some natural plants show a micro structure that gives them the capacity of being cleaned from any undesired particles on them by rainfall. A thorough study of the physical laws that lay behind this phenomenon, known as the lotus effect was conducted in order to obtain a set of useful design criteria for such surfaces. The problem of adapting this behaviour to artificially roughened surfaces is addressed by providing design criteria for superhydrophobic, water-repellent and self-cleaning surfaces according to the concrete performance desired for them. Different kind of manufacturing techniques are investigated and the production of patterned micro structured surfaces following two different manufacturing techniques is reported. The first is a combination of laser manufacturing and hot embossing on polystyrene. To compare geometry and functionality a non-silicon based lithography technique using copper laminated epoxy is described as a second approach. Hydrophobization of some surfaces was attempted. Results of characterisation and drop deposition tests of obtained surfaces are discussed.