Polymeric pH-sensitive membranes—A review

Significant progress has been achieved in recent years in the field of pH-sensitive membranes. In many cases, pH-sensitive membranes are systems for which the flux, membrane pore size, and solute rejection ratio may be manipulated by changing the pH. This review summarizes recent developments covering the preparation, pH-responsive properties, and applications in various disciplines. The pH-sensitive groups and the evaluation parameters for pH-sensitive membranes are reviewed and discussed. A variety of preparation methodologies, including blending, pore-filling, surface-grafting, and surface-coating techniques are described, and some of their salient features are highlighted. The flat-sheet form and hollow-fiber form pH-sensitive membranes are reviewed. Membrane pore size change and electroviscous effect are discussed. Furthermore, future perspectives of pH-sensitive membranes are discussed.