The modification of the surface properties of solids by complex fluid coatings is ubiquitous in our modern world. However, many fundamental questions about the solid/coating interface remain to be answered such as: (1) how does the surface quality vary with time, (2) what affects the adhesion between the surfaces. (3) how are the properties of thin complex fluid films influenced by the proximity of a solid interface, and (4) how may we modify these properties for particular functionality. In this paper, we report the results from two separate studies aimed at answering some of these questions. In each case, neutron reflectivity results obtained using the SPEAR reflectometer at the Manuel Lujan Jr. Neutron Scattering Center were used to probe the structure of the solid/complex fluid interface.