http://dx.doi.org/10.1021/nn1014006…
Block-Copolymer-Derived Water Purification Membranes
Providing access to clean water is a global challenge that will ultimately require improvements in the current state of water filtration systems.(13) Improvements in the technology of filtration systems could provide more affordable clean water for all through industrial, municipal, or small-scale filtrations. Ultrafiltration is just one of the current technologies that could realize significant improvements in separation efficacy from the incorporation of nanoporous membranes prepared using block copolymers.
Typical UF membranes are either quite permeable and not very selective, as in the case of phase-inversion-type membranes, or selective and not that permeable, as in the case of track-etched membranes.(14) To compete successfully in the UF arena, four main criteria are typically needed: high selectivity, high permeability, mechanical integrity, and resistance to fouling.(15) Nanoporous membranes derived from block copolymers have tremendous promise to fulfill all four of those requirements due to their narrow pore size distributions (high selectivity), high porosity (high permeability), and tunable chemical and physical properties, yet research in the science and engineering of such membranes is needed to combine all of these attributes into practical systems. Because flux is inversely proportional to thickness and costs are directly related to amount of material used, separation membranes containing thin, selective block copolymer layers are most desirable.(16) Creative strategies, such as that demonstrated by Yang et al., are needed to produce selective membranes that are mechanically stable and compatible with application-specific chemical, thermal, and biological environments. Furthermore, fabrication hurdles such as achieving proper pore alignment and scalable fabrication steps must also be overcome.(3) We highlight recent progress made toward other block-copolymer-derived nanoporous separation membranes and some of the obstacles that still remain.
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