Low-biofouling membranes prepared by liquid-induced phase separation of the PVDF/polystyrene-b-poly (ethylene glycol) methacrylate blend

Abstract

In the present work, the focus is laid on the formation, and low-biofouling properties of polyvinylidene fluoride (PVDF) membranes modified using an amphiphilic copolymer additive: polystyrene-b-poly (ethylene glycol) methacrylate (PS-b-PEGMA). PVDF was blended with PS-b-PEGMA and membranes were prepared by liquid-induced phase separation. The additive played a significant role on membrane formation, slightly decreasing surface porosity, reducing the shrinkage during phase separation, and increasing both the size and porosity of macrovoids. Owing to its numerous hydrophilic moieties, the copolymer was believed to promote solvent and nonsolvent exchanges during phase inversion. In addition, it significantly enhanced surface hydrophilicity and matrix hydration capability. Indeed, water was easily trapped by the PEGylated chains spread onto the surface and within the matrix, and then stored in the larger macrovoids. It led to an important reduction of protein adsorption, including bovine serum albumin (65%) and lysozyme (89%). Bacterial attachment tests revealed that adhesion of Escherichia coli and Staphylococcus epidermidis was almost totally prevented (over 99% reduction of attachment), which demonstrates the excellent efficiency of PS-b-PEGMA copolymer to provide PVDF membranes with low-biofouling properties.

NOM fouling behavior during ultrafiltration: Effect of membrane hydrophilicity

“…Among these materials, PEO-like polymers have attracted much attention due to their superior antifouling ability [37]. Although the kinetic and thermodynamic reasons for the protein resistance of PEO are still controversial, many researchers have attempted to mix the various PEO-containing amphiphilic copolymers with the usually used membrane materials to prepare the antifouling membranes [10][11][12][13][14][15][16][17][18][19][20][21]. The results confirmed that PEO chain had a trend to enrich on the membrane surface, which imparted good hydrophilicity to the hydrophobic membranes.…”

“…It is generally accepted that improving the intrinsic hydrophobic character of membranes is the most common method to avoid the non-specific adsorption between membrane and solute. Several hydrophilic materials were used to enhance antifouling ability of the conventional hydrophobic membranes, including PEO-like polymers [10][11][12][13][14][15][16][17][18][19][20][21][22], zwitterionic polymer [23][24][25], phospholipid polymer [26,27], heparin [28,29], zirconium oxide [30], titanium oxide [31], zeolite [32], silica [33], carbon nanotubes [34], graphene oxide [35], and their mixture [36]. Among these materials, PEO-like polymers have attracted much attention due to their superior antifouling ability [37].…”

Design of near-superhydrophobic/superoleophilic PVDF and PP membranes for the gravity-driven breaking of water-in-oil emulsions

“…Oppositely, immersing the polymer system would have directly led to the formation of a finger-like structure with a dense and smooth skin (WCA of about 85 ° [35] ). Therefore, the role of methanol is critical.…”

“…It also presented a tensile strength at break in the same range as that reported by Peng et al . ( < 1 MPa) [35] , which is rather low, but still enabled them to apply the membranes in membrane distillation. Therefore, it was believed that mechanical properties of the as-prepared membrane would be good enough to sustain a gravity-driven filtration process without being damaged.…”

Coating of reverse osmosis membranes with amphiphilic copolymers for biofouling control

“…Many studies showed that compared to uncoated membranes, less fouling was observed when membranes surfaces had a hydrophilic coating [10][11][12][13][14][15].…”