Chemically Tailored Multifunctional Asymmetric Isoporous Triblock Terpolymer Membranes for Selective Transport

Abstract

Membrane‐based separation of organic molecules with 1–2 nm lateral dimensions is a demanding but rather underdeveloped technology. The major challenge is to fabricate membranes having distinct nanochannels with desired functionality. Here, a bottom‐up strategy to produce such a membrane using a tailor‐made triblock terpolymer featuring miscible end blocks with two different functional groups is demonstrated. A scalable multifunctional integral asymmetric isoporous membrane is fabricated by the solvent evaporation‐induced self‐assembly of the block copolymer combined with nonsolvent‐induced phase separation. The membrane nanopores are readily functionalized using positively and negatively charged moieties by two straightforward gas–solid reactions. The pores of the post‐functionalized membranes act as target‐specific functional soft nanochannels due to swelling of the polyelectrolyte blocks in a hydrated state. The membranes show unprecedented separation selectivity of small molecules based on size and/or charge which demonstrates the potential of the proposed strategy to prepare next‐generation nanofiltration membranes.

High-performance asymmetric isoporous nanocomposite membranes with chemically-tailored amphiphilic nanochannels

“…50,51 The polyisoprene (PI) block of PS-b-PI was subsequently hydroxylated by a thiol-ene click reaction to obtain the P(HTMB-r-I) with various degrees of hydroxylation (DH) following a reported procedure. 48 Detailed description is shown in the Section 1.2 of expanded experimental part (ESI †).…”

“…Thin lms were prepared via spin-coating of a 2 wt% polymer solution in CHCl 3 on a silicon wafer at 3000 rpm for 1 min. Integral asymmetric isoporous membranes were prepared by using the SNIPS technique following a published procedure, 48 described in the ESI. † Titanium dioxide (TiO 2 ) sol nanoparticles (NPs) as an inorganic additives were in situ prepared by hydrolysis of TiO 2 precursors (titanium(IV) isopropoxide, TTIP) in an aqueous environment, following a reported procedure.…”

“…The membranes were further in situ post-functionalized using 1,3-propane sultone vapor, following our reported procedure. 48 Briey, the sulfonation reaction was accomplished by placing the PS-b-P(HTMB-r-I) derived membranes into a evacuated desiccator with a predetermined amount of 1,3-propane sultone at 50 C for 14 h.…”

“…Antifouling performance was determined by the static adsorption and dynamic ltration using ORÀ and RG6À aqueous solutions as foulants. Adsorption measurements were accomplished following the published procedure 48 (the detailed procedure is reported in the ESI †). The dynamic ltration of 0.1 mM aqueous solutions of the individual foulants was performed using the aforementioned dead-end stirred test cell at a transmembrane pressure of 1 bar at room temperature.…”

“…Recently we reported on a PI-b-PS-b-P4VP triblock terpolymer with partially functionalized PI blocks, which leads to a membrane with multifunctional pores built by the two mixed end blocks. 48 In this study, we prepared a novel tailor-made diblock copolymer, polystyrene-block-poly(4-(2hydroxyethyl-thio)-2-methyl butene-random-4-(2-hydroxyethylthio)-3-methyl butene-random-isoprene) (PS-b-P(HTMB-r-I)). It consists of a hydrophobic major block PS and a minor block P(HTMB-r-I) with randomly distributed isoprene (I), 4-(2hydroxyethyl-thio)-2-methyl butene and 4-(2-hydroxyethyl-thio)-3methyl butene (HTMB) units.…”