Macromol Rapid Commun. 2021 Nov 9:e2100632. doi: 10.1002/marc.202100632. Online ahead of print.
ABSTRACT
In this work, a block copolymer (BCP) consisting of poly((butyl methacrylate-co-benzophenone methacrylate-co-methyl methacrylate)-block-(2-hydroxyethyl methacrylate)) (P(BMA-co-BPMA-co-MMA)-b-P(HEMA)) was prepared by a two-step atom-transfer radical polymerization (ATRP) procedure. The obtained molecular weight of the BCP was 55100 g mol-1 featuring a poly(HEMA) content of 10 mol-% and about 10 mol-% of the benzophenone methacrylate as UV cross-linker within the statistical copolymer segment. BCP membranes were fabricated applying the self-assembly and non-solvent induced phase separation (SNIPS) process from a ternary solvent mixture of tetrahydrofuran (THF), 1,4-dioxane, and dimethylformamide (DMF); (2:1:1 in mass). The presence of a porous top layer of the integral asymmetric membrane featuring pores of about 30 nm was confirmed via scanning electron microscopy (SEM). UV-mediated cross-linking protocols for the nanoporous membrane were adjusted to maintain the open and isoporous top layer of the stabilized membrane. The swelling capability of the non-cross-linked and cross-linked BCP membranes was investigated in water, water/ethanol mixture (1:1), and pure ethanol using atomic force microscopy (AFM), proving a stabilizing effect of the UV cross-linking on the porous structures. Finally, the influence of the herein described cross-linking protocols on water-flux measurements for the obtained membranes was explored. As a result, an increased swelling resistance for all tested solvents was found, leading to an increased water flux compared to the pristine membrane. The herein established UV-mediated cross-linking protocol is expected to pave the way to a new generation of porous and stabilized membranes within the fields of separation technologies. This article is protected by copyright. All rights reserved.
PMID:34752668 | DOI:10.1002/marc.202100632
