(195b) Improving Poly(ethylene glycol) Protein-Resistance for New UF Membranes: A High Throughput Co-Solvent Approach

Membrane filtration operations inherently involve fouling and subsequent loss of performance. Poly(ether sulfone) (PES) is a membrane filtration material widely used in biotechnology because of its stability, ease of casting and low cost. However it binds proteins and exhibits fairly intense fouling during filtration of fluids containing biological molecules such as proteins. Poly(ethylene glycol) (PEG) is known as protein-resistant and harnessing it in membrane technologies has been suggested. Our patented photo-induced graft polymerization (PGP) approach can be used to graft poly(ethylene glycol) methyl ether methacrylate (PEG) without the presence of a photoinitiator. Here, we combine PGP with a newly developed high throughput platform (HTP), to graft PEG onto a PES membrane. The approach is fast, inexpensive and enables a large parameter space to be investigated with sound statistical validity. In an effort to maximize protein resistance by grafted PEG, four different co-solvent additives (dimethyl chloride (DCM), dimethylene formamide (DMF), dimethylene sulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP)) were added to grafting solution and examined for best filtration performance. Co-solvent effects were investigated using a fouling index and correlated with the degree of grafting calculated from FTIR-ATR spectra. The lowest fouling index was achieved (Fouling_Index = 0.03 +- 0.04) by mixing 0.2 mol/L PEG and 0.15 mol/L DCM in equal volume as compared with the Fouling_Index = 1.00 +- 0.05 for the unmodified as-received PES membrane. Hansen solubility paramters are used as a measure of affinity between to co-solvents and the PES surface.