Improvement of Antifouling Properties of Polyvinylidene Fluoride Hollow Fiber Membranes by Simple Dip Coating of Phosphorylcholine Copolymer via Hydrophobic Interactions

We present a simple surface modification method for improving the antifouling properties of polyvinylidene fluoride (PVDF) hollow fiber membranes for water treatment. Membranes were dip coated in a block copolymer of 2-methacryloyloxyethyl phosphorylcholine (MPC) and butyl methacrylate (BMA) (poly(MPC-co-BMA)) aqueous solution. Membranes coated with poly(MPC-co-BMA) at various coating concentrations exhibited higher antifouling properties than bare and MPC homopolymer-coated membranes, while showing higher water permeabilities after fouling. Fluorescence observation revealed the effect of coating concentration on poly(MPC-co-BMA) distribution within the hollow fiber membranes. The results of quartz crystal microbalance measurements showed that almost no bovine serum albumin was adsorbed onto the poly(MPC-co-BMA) coating, whereas it was highly adsorbed onto bare and MPC homopolymer coatings. We quantified the amount of poly(MPC-co-BMA) on the membrane before and after cleaning, using fluorescence microscopy. The poly(MPC-co-BMA) coating layer used in the hydrophobic interaction between BMA moieties and the PVDF membrane surface was quite stable.