Functionalization and post-synthetic modification (PSM) of metal-organic frameworks (MOFs) are two important routes to obtain MOFs with full potential in mixed matrix membrane (MMM) fabrication. We synthesized UiO-66 and two derivatives UiO-66-NH 2 and UiO-66-NH-COCH 3 with less than 50 nm particle size. The CO 2 uptakes at 10 bar in the two functionalized UiO-66s were improved by 44% and 58%, respectively, with respect to the pristine solid. The MOF nanoparticles were incorporated into the highly permeable polymer 6FDA-DAM, making MMMs with 5-24 wt% particle loadings. All fillers and membranes were characterized accordingly, and their gas separation performances were evaluated by feeding CO 2 /CH 4 equimolar mixtures at 2 bar pressure difference at 35°C. CO 2 permeability (P CO2) of pristine 6FDA-DAM (P CO2 = 997 ± 48 Barrer, α CO2/CH4 = 29 ± 3) increased by 92% with 20 wt% UiO-66 loading, while maintaining the CO 2 /CH 4 selectivity. Improvements of 23% and 27% were observed for P CO2 with the same 20 wt% loading of UiO-66-NH 2 and UiO-66-NH-COCH 3 , respectively. The α CO2/CH4 was improved up to 16% using both functionalized UiO-66 type MOFs. The best separation performance in this work was obtained with 14 wt% UiO-66 MMM (P CO2 = 1912 ± 115 Barrer, α CO2/CH4 = 31 ± 1), 16 wt% UiO-66-NH 2 MMM (P CO2 = 1223 ± 23 Barrer, α CO2/CH4 = 30 ± 1) and 16 wt% UiO-66-NH-COCH 3 MMM (P CO2 = 1263 ± 42 Barrer, α CO2/CH4 = 33 ± 1) at 2 bar feed pressure difference. The measurement was also conducted with various binary compositions (CO 2 = 10-90%), both at low and high pressures up to 40 bar at 35°C, showing no pressure-related CO 2-induced plasticization. The atomistic modelling for the MOF/polymer interface was consistent with a moderate MOF surface coverage by 6FDA-DAM which did not play a detrimental role in the membrane performance. with improved permeation and selectivity have been described extensively, including the very promising approach of mixed matrix membranes (MMMs) [5]. MMM technology exploits the distinct and complementary properties of both polymer and inorganic materials with different physicochemical properties, selectivity and permeation flux for their selective separation. Various materials, generally porous, such as carbon molecular sieves (CMS) [6,7], zeolites and silicas [7,8], metal oxides [9], carbon nanotubes (CNTs) [10], metal organic frameworks (MOFs) [11-14], graphene [15,16], etc. have been embedded in continuous polymer

The increasing demand for energy efficient separation processes fosters the development of new high performance polymers as selective separation layers for membranes. PIM-1 is the archetypal representative of the class of polymers of intrinsic microporosity (PIM) which are considered most promising in this sector, especially for gas separations. Since their introduction, PIMs stimulated a vast amount of research in this field and meanwhile evolved to the state-of-the-art in membrane technology for gas separation. The major obstacle for extending the practical membrane application is their strong tendency to physical aging. For the first time, investigations by broadband dielectric spectroscopy (BDS) addressing molecular dynamics and conductivity in PIM-1 are presented. As chain packing during film formation from the casting solution and physical aging are key factors determining the separation performance of PIMs as membrane materials, characterization of the molecular mobility in such materials as revealed by BDS will provide valuable information for further development and optimization.

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The interest in (micro)porous systems is greater than ever before with microporous polymers finding application in areas such as gas storage/separation and catalysis. In contrast to the vast majority of publications on microporous polymers seeking ever higher values for surface area or uptake capacity for a particular gas, this work presents a means to render a microporous system responsive to electromagnetic stimuli. The incorporation of a diarylethene (DAE) derivative in the backbone of a polymer of intrinsic microporosity (PIM) produces a microporous system that exhibits photochromism as proven by UV−vis absorption and NMR studies. In the resulting DAE-PIM, surface area is not a fixed unalterable property but can be influenced by the external and nondestructive stimulus light in a reversible manner. Furthermore, in combination with Matrimid, free-standing membranes can be produced that display light-switchable diffusivity and permeability for carbon dioxide and oxygen. In this way, material scientists are offered the potential to employ only one system that can assume several states with different properties for each.

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