Interfacial properties play an increasingly important role in gas/liquid devices as the characteristic dimensions become smaller. This contribution describes the application of microstructured devices to gas/liquid systems being studied at the Institute for Micro Process Engineering. In microstructured reactors, good wettability is desired to maximize the gas/liquid interfacial area. In this work, the material wettability is demonstrated to impact the flow pattern as well as reaction conversion. Using a membrane to stabilize a gas/liquid interface for the purpose of gas/liquid separation requires a robust and poorly wettable membrane. A Gore PTFE membrane is able to achieve a stable interface and separate CO2 from water. Since the material wettability has a decisive impact on the operation of gas/liquid reactors and separators, controlling this property could improve the performance of microstructured devices. Thin films of silicon and carbon have been deposited with PECVD. The films demonstrate a promising method to alter and control surface properties.