Supported ionic liquid phase (SILP) catalysts are an extremely promising class of materials that combine advantageous concepts from both homogeneous and heterogeneous catalysis. Optimized SILP catalysts should exhibit a thin, homogeneous, and continuous film of the ionic liquid (IL) to avoid pore blocking and to ensure a good accessibility of the catalyst. Yet, the interactions between the IL and the support, which determine the formation of such a film, are still poorly understood. We investigate here in a systematic way the deposition of three imidazolium-based ILs on silica supports with different surface areas and morphologies using 1 H magic angle spinning solidstate nuclear magnetic resonance spectroscopy. We demonstrate that the point of complete surface wetting can be determined by the disappearance of the 1 H resonance of isolated silanol groups and that this point depends both on the textural properties of the support material and the chemical properties of the IL. 1 H chemical shifts also provide valuable insight into hydrogen bonding interactions within the IL and between the IL and the support. They indicate cleavage of the anion−cation hydrogen bonds upon IL deposition and the formation of new hydrogen bonds with the silica surface.