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Self-assembled membranes with uniform pore sizes tunable in 0.1-nm steps have been developed for organic solvent nanofiltration. 

Modulation of the luminescent radiation of a GaAs solar cell to transmit information wirelessly is explored. The impulse response is measured to determine the transmission speed of binary symbols using square pulses. 

As wastewater reclamation and reuse technologies become more critical to meeting the growing demand for water, a need has emerged for separation platforms that can be tailored to accommodate the highly varied feed water compositions and treatment demands of these technologies. Nanofiltration (NF) membranes based on copolymer materials are a promising platform in this regard because they can be engineered at the molecular scale to address an array of separation process needs. Here, for example, a resilient NF membrane is developed through the design of a poly(trifluoroethyl methacrylate- co -oligo(ethylene glycol) methyl ether methacrylate- co -glycidyl methacrylate) [P(TFEMA-OEGMA-GMA)] copolymer that can be dip-coated onto hollow fiber supports. By exploiting the microphase separation of the oligomeric ethylene glycol side chains from the copolymer backbone and by elucidating the processing–structure–property relationships for the dip-coating process, membranes with pores 2 nm-in-diameter that exhibit a hydraulic permeability of 15.6 L m −2 h −1 bar −1 were generated. The GMA repeat units were functionalized post-coating with hexamethylene diamine to incorporate positively-charged moieties along the pore walls. This functionality resulted in membranes that rejected 98% of the MgCl 2 from a 1 mM feed solution. Moreover, the reaction with the diamine crosslinked the copolymer such that the membranes operated stably in ethanol, an organic solvent that damaged the unreacted parent membranes irreparably. Finally, the stability of the crosslinked P(TFEMA-OEGMA-GMA) copolymer resulted in membranes that could operate continuously for a 24 hour period in aqueous solutions containing 500 ppm chlorine without exhibiting signs of structural degradation as evidenced by consistent rejection of neutral probe solutes. These results demonstrate how resilient, charge-selective NF membranes can be fabricated from microphase separated copolymers by engineering each of the constituent repeat units for a directed purpose. 

Self-assembled materials are attractive for next-generation membranes. However, the need to align self-assembled nanostructures (e.g. cylinders, lamellae) and the narrow stability windows for ordered bicontinuous systems present serious challenges. We propose and demonstrate a novel approach that circumvents these challenges by exploiting size-selective transport in the water-continuous medium of a nanostructured polymer templated from a self-assembled lyotropic H 1 mesophase. Optimization of the mesophase composition enables high-fidelity retention of the H 1 structure on photoinduced cross-linking. The resulting material is a mechanically robust nanostructured polymer possessing internally and externally cross-linked nanofibrils surrounded by a continuous aqueous medium. Fabricated membranes show size selectivity at the 1- to 2-nm length scale and water permeabilities of ~10 liters m −2 hour −1 bar −1 μm. Moreover, the membranes display excellent antimicrobial properties due to the quaternary ammonium groups on the nanofibril surfaces. These results represent a breakthrough for the potential use of polymerized lyotropic mesophase membranes in practical water purification applications.