Modular Synthesis of Functional Block Copolymers by Thiol–Maleimide “Click” Chemistry for Porous Membrane Formation

Abstract

In this work, a modular strategy for the synthesis of block copolymers (BCPs) is presented using the quantitative reaction of a maleimide with a thiol. For this purpose, anionic polymerization and atom transfer radical polymerization were used to generate end-functionalized homopolymers. For proof of concept, polystyrene-b-poly(2-hydroxyethyl methacrylate) (PS-b-PHEMA) BCPs with different molecular weights and segment ratios were synthesized, leading to high molecular weights of 128 kg mol −1 with a polydispersity index of 1.18. Additionally, the synthesis of polystyrene-b-poly(2-aminoethyl methacrylate) and polystyrene-b-poly(2-hydroxyethyl methacrylate)-b-poly(2,2,2-trifluoroethyl methacrylate) terpolymer was investigated. The access of PS-b-PHEMA to isoporous integral membranes by the self-assembly and non-solvent-induced phase separation (SNIPS) process was confirmed by scanning electron microscopy. The produced SNIPS membranes featured a maximum water flux of 608 L bar −1 h −1 m −2 and a maximum transmembrane pressure of 2.7 bar. This modular synthesis system demonstrates the utility of scalable SNIPS membrane formation for biomedical and water filtration applications.

Polyacrylonitrile-containing amphiphilic block copolymers: self-assembly and porous membrane formation

“…5,19,21 For example, the introduction of PHEMA as hydrophilic block bearing accessible hydroxy-moieties by Schöttner et al 22 paved the way to multiple post-modification possibilites. 23–26…”

“…5,19,21 For example, the introduction of PHEMA as hydrophilic block bearing accessible hydroxy-moieties by Schöttner et al 22 paved the way to multiple post-modification possibilites. [23][24][25][26] The formation of a membrane via the SNIPS process includes three essential steps: preparing a semi-concentrated solution of the BCP in a solvent mixture, casting the membrane solution by doctor blading and, after an appropriate evaporation time, freezing the membrane in its non-equilibrium state by immersion in a precipitation bath. The process itself is complex and many parameters have to be considered, whilst being strongly dependent on each other, when introducing a new BCP.…”

Efficient end-group functionalization and diblock copolymer synthesis via Au(iii) polymer reagents

“…One method to alleviate these synthetic concerns is to use ''click''-type reactions due to their enhanced kinetics and chemoselectivity. 4 Effective examples of using ''click''-type reactions for the construction of diblock copolymers include thiol-ene reactions, 5,6 Cu(I)-catalyzed azidealkyne cycloadditions (CuAAC), [7][8][9] Diels-Alder cycloadditions, 10,11 and more recently developed selective routes such as Sulfur(VI) fluoride exchange (SuFEx) reactions. 12 Thus, ''click''-type chemistry allows for the facile synthesis of these diblock copolymers that otherwise would be synthetically inaccessible.…”

An anchor for help: a cross-linking moiety for block copolymer membrane stabilization for ultrafiltration applications in water

“…For HEMA-containing polymer systems, mole fractions of around 10% have been found to enable porous cylinder formation. 15,30 For the SNIPS process, the polymer was dissolved in a mixture of THF, DMF and 1,4-dioxane (2 : 1 : 1 by weight) in a semi-concentrated solution featuring 0.5% of CuCl 2 to enhance micellization and processability through coordination, similar to previous work published 22 and 5% BP was added. This polymer solution was cast on a PE/PP nonwoven with a doctor blade with a blade gap of 200 mm.…”