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N-isopropylacrylamide (NIPAAM) modified cellulose acetate ultrafiltration membranes

Gorey, Colleen, Escobar, Isabel C.
Journal of membrane science 2011 v.383 no.1-2 pp. 272-279
adsorption, ammonium nitrate, artificial membranes, cellulose acetate, ceric ammonium nitrate, desorption, fouling, hydrophilicity, hydrophobicity, phase transition, polymers, temperature, ultrafiltration
A potentially low fouling membrane was developed by attaching a stimuli-responsive polymer layer on the surface, which offered the potential to collapse or expand the polymer layer with change in temperature. The phase change arose from the existence of a lower critical solution temperature (LCST) such that the polymer precipitated from solution as the temperature was increased. This capability was exploited to control adsorption/desorption on a cellulose acetate membrane. A temperature decrease caused the layer to expand into a rough hydrophilic state while a temperature increase caused a collapse into a smooth hydrophobic state. By cycling the temperature of the modified membrane above and below the LCST, a dynamic surface was created with the potential to reduced fouling.I n this study, N-isopropylacrylamide (NIPAAM) was used as the temperature-responsive polymer; it has an LCST of 32°C, and was grafted to a cellulose acetate ultrafiltration membrane surface using cerium ammonium nitrate as an initiator. While surface activation was observed at the nano-scale level, no improvements in fouling control were observed during operation.