Fabrication of a polymeric coating layer with unique micro-spherical structure on water treatment membranes

The fabrication of stable, non-leachable spherical polymers on solid surfaces, particularly on water treatment membranes, has the advantage of high surface area and high permeability, which is beneficial for anti-fouling coatings of water treatment membranes. We describe a straight, one-step generation of spherical polymeric coatings on nanofiltration membrane surface which was performed by emulsion co-polymerization of styrene and polyethylene glycol methacrylate (PEGMA) in water. The chemical characterization of the membrane surface and its coating layer was done by Fourier transform infrared spectroscopy (FTIR). Microscopic images showed micelles of 30 - 120 μm size. PEGMA with molecular weight of 526 g/mole was found to have a critical micelle concentration (CMC) value of 0.05 M, which is much lower than its concentration in the polymerization mixture. Hence, in the copolymerization reaction PEGMA-526 created stable micelles and also acted as a surfactant in respect to the styrene. The produced poly(PEGMA) may also act as a surfactant due to its amphiphilic nature. A homogeneous surface morphology on the NF membrane was achieved, with spherical polymeric micelles that have a large surface area.