Super-hydrophobic surfaces are of considerable interest as they can reduce friction losses and thus lead to substantial reductions in the energy consumption of water distribution networks. However, super-hydrophobic surfaces are not durable, as they are known to lose their friction-reducing properties rapidly due to loss of small air-pockets in the roughness elements of the surface. This thesis describes the development and testing of a novel porous low-friction surface with recoverable

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... drophobicity for use under fully turbulent water flow conditions. Preliminary experiments carried out as part of this dissertation showed that samples with super-hydrophobic coatings immersed in water lost their super-hydrophobicity quickly due to depletion of trapped air. Furthermore, the loss of particles on the surface that form the surface structure can lead to irreversible loss of super-hydrophobicity. Therefore a durable super-hydrophobic surface was designed and manufactured, using sintered soda-lime glass granules that provided an increased level of particle bonding compared to coatings. The surface of the materials was made hydrophobic through a reaction with one of several surface modifying agents. Combinations of granules of five different particle sizes and three different surface modifying agents (hexamethyldisilazane, trichloro(1H,1H,2H,2H-perfluorooctyl)silane and 1H,1H,2H,2H-perfluorooctyltriethoxysilane) were considered. The hydrophobicity of the materials was analysed by measuring the water contact angle. The best performing material, sample ST, showed a mean water contact angle of 153°. The surface and structure of the best performing samples were characterised using scanning electron microscopy (SEM), x-ray tomography and Fourier Transformed Infra-red (FTIR) spectroscopy. FTIR spectroscopy confirmed the reaction between trichloro- (1H,1H,2H,2H-perfluorooctyl)silane and the soda-lime glass substrate. SEM micrographs showed that samples formed with smaller particle sizes presented 30% less peak areas than [...]