The production and use of clean and efficient energy has been a prominent issue of the early 21st century. The rising energy crisis has been prompting social, economic, and scientific debates regarding novel sources and sustainable energy strategies, increasing the global willingness to embrace the delivery of energy through the use hydrogen (H2) as a potential solution. (…) Current separation technologies for hydrogen purification comprise pressure swing adsorption and amine-based solvent systems, which are highly energy intensive and have relatively low capacity . Thus, the development of high performance and cost-effective H2 purification technologies is of vital importance. From both the engineering and the economic perspective, membranes are considered a very promising technology and show clear advantages comparatively to other absorption processes, namely small scale of the equipment, reduced environmental impact, ease of incorporation into existing processes, low energy consumption and operating costs . (…) Throughout this project, a variety of task-specific PILs with different structural features will be synthesized using appropriated synthetic routes. Several techniques will be researched to prepare dense thin films in order to provide membranes with higher gas permeation fluxes. (…) These membranes will be characterized using thermal analysis and advanced spectroscopic and physico-mechanical techniques. Gas permeation and sorption studies will be performed in order to interpret the relationships between PIL structure and gas transport. The determination of gas permeation properties and evaluation of CO2/H2 separation performances under the relevant technological operating conditions are also clear targets.