doi:10.1039/c7ce00086cengCacho-Bailo, FernandoEtxeberría-Benavides, MirenKarvan, OguzTéllez, CarlosCoronas, JoaquínSequential amine functionalization inducing structural transition in an aldehyde-containing zeolitic imidazolate framework: Application to gas separation membranesART-2017-98452A modification in the gas separation performance of zeolitic imidazolate framework (ZIF)-supported hollow fiber (HF) membranes by means of an imine-condensation functionalization reaction carried out by microfluidics is reported. The accommodation of voluminous amine molecules in the SIM-1, Zn(4-methyl-5-imidazolecarboxaldehyde)2, also known as ZIF-94, sod structure during the functionalization reaction caused the ZIF atoms to be rearranged in a less dense rho structure, with a wider pore diameter and a diminished CO2 affinity. These changes had effects on the membrane performance, resulting in an enhanced CO2 permeance while maintaining a good permeance-selectivity balance. ZIF aldehyde-containing SIM-1 membranes were earlier prepared on the inner side of polymeric P84® HF using a microfluidic approach. The SIM-1 membranes displayed very interesting results in the separation of gas mixtures of great relevance to the natural gas field. High selectivities in the separation of He/CH4 (160), H2/CH4 (136) and CO2/CH4 (38) mixtures were achieved, and these are the first SIM-1 membranes with such a high separation performance to the best of our knowledge. These SIM-1 membranes were in situ stepwise functionalized with long-chain amine solutions, namely, hexyl- and nonylamine. Microfluidics allowed the easy sequential implementation of this post-reaction step in the membrane fabrication procedure. An imine-condensation reaction took place between the aldehyde groups in the 4-methyl-5-imidazolecarboxaldehyde ligand forming SIM-1 and the corresponding amines. The extent of the reaction was analyzed by FTIR, TGA and XRD, together with the changes in the textural properties and the adsorption capacities.2017http://zaguan.unizar.es/record/7069310.1039/c7ce00086chttp://zaguan.unizar.es/record/70693oai:zaguan.unizar.es:70693info:eu-repo/grantAgreement/ES/DGA/T05info:eu-repo/grantAgreement/ES/MINECO/MAT2013-40566-Rinfo:eu-repo/grantAgreement/ES/MINECO/MAT2016-77290-RCRYSTENGCOMM 19 (2017), [20 pp.]All rights reservedhttp://www.europeana.eu/rights/rr-f/info:eu-repo/semantics/openAccess