Photo-irradiation for preparation, modification and stimulation of polymeric membranes

Abstract

The recent developments in combining photo-irradiation-base d and membrane technolo-gies are analyze d i n this review. It is emphasize d that the ef fects o f photo-initiate d reactions onto properties of polymeric membranes will largely depend on the nature of the mem-brane’s barrier (i.e., porous vs. non-porous, uncharge d vs. charge d, or involving affinity interactions). For de novo preparation of membranes from low molar mass or soluble pre-cursors, photo-initiate d polymerization and photo-cross-linking are the main pathways, while photo-degradation for pore formation is only rarely applie d. Membrane functional-ization (modification) is describ e d with many examples, organize d into photo-cross-linking of membranes and photo-graf ting of membrane surfaces, either via "grafting-to" or via "grafting-from"€ routes. Photo-stimulation of barrier properties is an attractive concept to create stimuli-responsive membranes, and various ways to use photo-chromicmoieties for that purpose are discusse d. Overall, photo-irradiation-base d methods can be very versatile enabling te chnologies to improve the performance of polymeric membranes in technical separations (e.g., in gas separation, pervaporation, ultra- and microfiltration or as membrane adsorbers) and other processes (e.g., for controlled release or in sensor systems), and they will definitely also contribute to the development of entirely novel membrane-base d materials.