Ultrafiltration (UF) membrane fouling remains as one of the major operational difficulties in this membrane separations technology. In this regard surface nano-structuring via atmospheric pressure plasma-induced graft polymerization (APPIGP) is a promising technology for imparting anti-fouling propensities to membrane surfaces by generating high density of surface active sites on membrane surfaces, from which vinyl monomers are graft polymerized to create dense, terminally and covalently-bonded polymer brush layers. In the present study, the APPIGP approach was applied, using acrylic acid and 2-hydroxyethyl methacrylate monomers, to nano-structuring polysulfone (PSf) surrogate membrane surfaces and its effectiveness was investigated with respect to plasma treatment conditions (i.e., reactive plasma gas species, radio frequency (RF) power, and plasma exposure time) and grafting conditions (i.e., initial monomer concentration, reaction temperature, and grafting time). The resulting modified substrate properties (chemistry and topography of polymer brush layers) were characterized by atomic force microscopy (AFM), contact angle measurement, and X-ray photoelectron spectroscopy (XPS). The results showed that significant reduction of surface wettability was achieved upon graft polymerization. Moreover, surface hydrophilicity and roughness of polysulfone substrates can tuned by varying plasma and grafting conditions, indicating that the APPIGP methodology could be beneficial for surface modification of commercial polysulfone UF membranes for improving the surface hydrophilicity and hence fouling mitigation.

Surface nano-structuring with polymer brush layers for fouling resistant ultrafiltration (UF) membranes

248th National Meeting (2014)

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