Fouling-resistant properties of a surface-modified poly(ether sulfone) ultrafiltration membrane grafted with poly(ethylene glycol)-amide binary monomers

Abstract

Poly(ether sulfone) (PES) membrane surfaces were modified by grafting poly(ethylene glycol) methyl ether methacrylate (PEG) with vinylamides including N-vinylformamide (NVF), N-vinylacetamide (NVA) or N-methyl-N-vinylacetamide (MVA) via a photo-induced graft polymerization (PGP) method coupled with a recently developed high throughput platform (HTP) technology. Synergistic fouling reduction by grafting PEG with a vinylamide was observed. Fouling was orchestrated using 1 mg mL −1 bovine serum albumin (BSA) as a model foulant. The optimum composition for grafting each PEG–vinylamide pair in terms of fouling reduction, permeation resistance and protein sieving was sought. Fouling index, ℜ, was used to quantify the intensity of fouling. The degree of grafting (DG) of PEG and vinylamides were analyzed using FTIR–ATR spectroscopy. Lower fouling (reduced ℜ value) was observed with mixed monomer as compared with single monomer grafts. The lowest fouling index (ℜ = − 0.56 ± 0.29) was obtained by grafting 0.06 mol L −1 PEG and 0.14 mol L −1 NVA. This also gave a higher permeability as compared with that before BSA fouling. Using a Hansen solubility analysis with degree of grafting, the data suggests pore-narrowing by grafting during the surface modification process.