Smart covalent organic networks (CONs) with "on-off-on" light-switchable pores for molecular separation

Jiangtao Liu; Shaofei Wang; Tiefan Huang; Priyanka Manchanda; Edy Abou-Hamad; Suzana P Nunes

doi:10.1126/sciadv.abb3188

Smart covalent organic networks (CONs) with "on-off-on" light-switchable pores for molecular separation

Sci Adv. 2020 Aug 19;6(34):eabb3188. doi: 10.1126/sciadv.abb3188. eCollection 2020 Aug.

Authors

Jiangtao Liu¹, Shaofei Wang¹, Tiefan Huang¹, Priyanka Manchanda¹, Edy Abou-Hamad², Suzana P Nunes¹

Affiliations

¹ Biological and Environmental Science and Engineering Division (BESE), Advanced Membranes and Porous Materials Center (AMPM), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
² Core Labs, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia.

Abstract

Development of the new-generation membranes for tunable molecular separation requires materials with abilities beyond strict separation. Stimuli response could remotely adjust the membrane selectivity. Azobenzene derivatives can be photo-switched between trans and cis isomers under ultraviolet or visible light. Here, the azobenzenes were implanted as light switches to bridge the flexible cyclen building blocks. The smart covalent organic network membranes fold and unfold as origami that can be photo-switched between on-state (large) and off-state (small) pores. The cis membranes with off state under ultraviolet (UV) light have higher dye rejection than trans membranes with on-state channels. By controlling the trans-to-cis azobenzene isomerization via UV/Vis light, the pore size can be remotely controlled at the molecular level and the solvent permeance and dye rejection can be dynamically tuned.

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