Graft coupling of PEO to mixed cellulose esters microfiltration membranes by UV irradiation

Protein fouling is a critical factor governing membrane performance in various filtration processes. In this study, we report a new surface modification technique to modify 0.22 μm mixed cellulose esters membranes to reduce protein fouling. The first step in this modification process involves coating of the membrane with a monolayer of allyldimethylchlorosilane (ADCS). The silanized membrane is then covalently linked to Pluronic F127, a triblock copolymer of polyethylene oxide and polypropylene oxide (PEO–PPO–PEO) by UV irradiation at wavelengths >215 nm. The presence of PEO groups on the membrane surface increased the wettability of the membrane. Contact angle measurements confirmed that the degree of Pluronic grafting on the silanized membrane was a function of the UV exposure time. The hydraulic permeability and flux decline of the modified membrane during bovine serum albumin (BSA) filtration were nearly identical to the unmodified membrane. The modified membranes exhibited better cleaning characteristics compared to unmodified membranes upon back flushing with saline solution.