Fig. 1: Synthesis strategies for DHTA-Hz and DHTA-Hz-15C5 membranes.

a In–situ growth of DHTA-Hz selective layer on AAO support via interfacial polymerization. Crown ether 15C5 was introduced into the one–dimensional channel of the selective layer to form the DHTA-Hz-15C5 membrane. b SEM image of the surface of DHTA-Hz membrane. c SEM cross–sectional image of DHTA-Hz membrane. d Solid–state 13C CP/MAS NMR spectrum of DHTA-Hz membrane. e ACTEM image of DHTA-Hz membrane. f SEM image of the surface of DHTA-Hz-15C5 membrane. g Photograph of the DHTA-Hz membrane.