Cacho-Bailo, FernandoEtxeberría-Benavides, MirenKarvan, OğuzTéllez, CarlosCoronas, Joaquín2017Cacho-Bailo , F , Etxeberría-Benavides , M , Karvan , O , Téllez , C & Coronas , J 2017 , ' Sequential amine functionalization inducing structural transition in aldehyde-containing zeolitic imidazolate framework: application to gas separation membranes : application to gas separation membranes ' , CrystEngComm , vol. 19 , no. 11 , pp. 1545-1554 . https://doi.org/10.1039/C7CE00086C1466-8033researchoutputwizard: 11556/385Publisher Copyright: © The Royal Society of Chemistry.A 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.101246440enginfo:eu-repo/semantics/openAccessjournal article10.1039/C7CE00086CZeolitic imidazolate framework (ZIF)Supported composite hollow fiber membraneZIF-94Gas separationZeolitic imidazolate framework (ZIF)Supported composite hollow fiber membraneZIF-94Gas separationGeneral ChemistryGeneral Materials ScienceCondensed Matter PhysicsFunding InfoFinancial support (MAT2013-40556-R, MAT2016-77290-R) from_x000D_ the Spanish MINECO, the Aragón Government (DGA, T05), the_x000D_ European Social Fund and FEDER is gratefully acknowledged.Financial support (MAT2013-40556-R, MAT2016-77290-R) from_x000D_ the Spanish MINECO, the Aragón Government (DGA, T05), the_x000D_ European Social Fund and FEDER is gratefully acknowledged.http://www.scopus.com/inward/record.url?scp=85014959241&partnerID=8YFLogxK