Hybrid "organic-inorganic" membranes are synthesized by growing a functionalized mesoporous "sol-gel"-derived SiO2 network into a hydrophobic fluorinated polymer. Processing guidelines are proposed to optimize the porosity at the macro-, meso- and micro-scales by templating the surface of the membrane through a modification of the thermal processing at 30-80 degrees C in air. Such a hierarchical design exploits the benefits of the facile water retention of the breath figure to produce membranes with high proton conductivity (50 mS cm(-1) at 70 degrees C) under 100% relative humidity and develops the surface area and the interfacial area between the hydrophobic and hydrophilic domains.