It is planned to investigate the aqueous interface of smooth hydrophobic polymer-coated substrates by neutron reflectivity. The water density profile determination will allow the hydrophobic water gap to be characterized both in terms of spatial extent and of nature (a dewetted region, a depleted region with water reduced density, or a precursor gas region?). In particular the effects of dissolved gasses (inert or non polar such as Ar, N2, CO2, or polar such as CO) in the water will allow insights to be gained.