Quaternization cross-linking of hyperbranched polyethylene-graft-poly (diethylaminoethyl methacrylate) as antimicrobial separation layer of molecular sieving membrane

Positively charged composite membranes with polyethylene-based antimicrobial separation layers are conve-niently developed herein for precise molecular sieving. Quaternization cross-linking between hyperbranched polyethylene-graft-poly(diethylaminoethyl methacrylate) and 1,2-dibromoethane constructs porous networks with abundant quaternary ammonium groups. Modified membranes exhibit different interception capabilities for anions, cations, and neutral molecules. We explain the possible sieving mechanisms with respect to size exclu-sion, the Donnan effect, and the intrapore energy barrier. A strongly positively charged separation layer in-troduces the electrostatic interaction which has different effects on cationic, anionic, and neutral molecules during filtration. Membranes prepared by the simple quaternization cross-linking strategy can efficiently sepa-rate molecular mixtures with different dimensions or charges. Moreover, the plentiful quaternary ammonium groups endow the membranes with favorable antimicrobial activity against Gram-positive E. coli and Gram -negative S. aureus.