Rubbery Organic Frameworks-Tuning the Gaz-Diffusion through Dynameric Membranes

High permeability whilst keeping a reasonable selectivity is the most important challenge in developing membranes for gas separation. Valuable performances are usually obtained with membranes for which the gas transport is controlled by the gas-diffusivity in glassy polymers and by gas-solubility in rubbery polymers. During the last decade, important advances in this field are related to the molecular control of the gas separation properties. The combination/replacement of classical glassy polymers with metal-organic frameworks (MOFs, ZIFs, zeolites…) embeded in polymeric matrixes provided reasonable permeability through porous free volume network and high selectivity due to so-called “selectivity centers”, specifically interacting with the gas molecules. Despite the impressive progress, important difficulties are observed to get dense mechanically stable thin layer MOFs on various supports. Taking advantage of high permeabilities observed with the dynamic covalent rubbery polymers and to their flexible casting properties, there should be very interesting to build rubbery organic frameworks-ROFs, as alternative for molecularly controlled membranes for gas separation. Here we use low macromolecular amino-functional connectors and aldehyde core centers in order to constitutionally generate such adaptrive dynameric ROFs. Differently to classical rubbery polymeric membranes the ROFs performances depend univocally of diffusionl behaviors of gas molecules through the network. For all gases, a precise molecular composition of linear and star-type macromonomers generates an optimal free volume for a maximal diffusion through the matrix. These results should initiate new interdisciplinary discussions about highly competitive systems for gas separation, constitutionally controlled at the molecular scale.<br/><br/>Y. Zhang, M. Barboiu, <i>Chem. Rev.</i> 2016, <i>116</i>, 809-834<br/>G. Nasr, A. Gilles, T. Macron, C. Charmette, J. Sanchez, M. Barboiu, Israel J. Chem. 2013, 53, 97-101.<br/>G. Nasr, T. Macron, A.Gilles, C. Charmette, J. Sanchez, M.Barboiu, Chem. Commun.,2012, 4, 11546.<br/>G. Nasr, T. Macron, A. Gilles, Z. Mouline, M. Barboiu, Chem. Commun. 2012, 48, 6827-6829.<br/>G. Nasr, T. Macron, A. Gilles, E. Petit, M. Barboiu, Chem. Commun.<b>,</b> 2012, 48, 7398-7400.