The separation and purification of gases is critical in many applications such as chemical purification and carbon capture and sequestration. Current gas separation processes are highly energy intensive and require large physical footprints. This is because many of these processes rely on “active” separation techniques such as adsorption and absorption systems. Membranes can greatly reduce both the parasitic energy costs and physical footprint, but current membranes are typically polymer-based and suffer from an inherent trade-off between permeability and selectivity thereby limiting their theoretical performance. Hybrid organic/inorganic membranes can offer enhanced avenues for gas transport not attainable in pure polymer or inorganic materials. Our research will focus on the fundamental understanding and development of hybrid membranes, with specific attention devoted towards control of the inorganic phase, to further enhance the performance of hybrid membranes. We will investigate how interfacial interaction, inorganic nanomaterial size, and inorganic porosity effects polymer properties such as morphology and structure as well as unique contributions to gas permeability and selectivity.