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The document is a contents list for the Journal of Materials Chemistry A, a publication by the Royal Society of Chemistry. The journal focuses on materials with applications in energy and sustainability. It includes information about the articles featured in the current issue, as well as details about the editorial staff and subscription information. The document also provides information for authors interested in submitting material for publication, including details on how to submit manuscripts and the types of submissions the journal welcomes. It lists the titles and authors of various papers and reviews that have been published in the journal, covering topics such as flexible nanocellulose films, electrochemical measurements, battery technologies, photocatalysts, and sensors. Additionally, it includes a correction for a previous paper on nickel carbonate as an electrocatalyst. [Extracted from the article]

A proton exchange membrane (PEM) is a crucial component for the effective and stable operation of energy conversion and storage devices, such as fuel cells, water electrolyzers, and redox flow batteries. However, perfluorinated sulfonic acid (PFSA) membranes—the most widely used PEM—have ultimate limitations of low proton selectivity to other active species because of their wide and randomly connected proton channels. Many attempts have been made to enhance the ion selectivity through morphology control, but it is still necessary to achieve significant improvement to overcome the permeability–selectivity trade-off. In this study, we demonstrate an ultrathin (∼30 nm) PFSA membrane with highly ordered hydrophilic domains. The well-controlled nanostructures are generated from the pre-aligned PFSA ionomers on the aqueous substrate, and further morphology development in the size and orientation of domains, and crystallinity, is finely adjusted via thermal annealing. Through this bottom-up morphology control, the ultrathin membrane has highly aligned ion channels with 55% crystallinity, resulting in about 800 times higher proton selectivity and 2 orders of magnitude lower areal resistance compared to 25 μm-thick PFSA membranes (Nafion 211). Furthermore, when the ultrathin membrane is applied to a vanadium redox flow battery (VRFB), the cell shows higher energy efficiency (∼76%) than a cell with a commercial Nafion membrane at the current density of 200 mA cm−2. [ABSTRACT FROM AUTHOR]

We report a systematic rheological analysis of perfluorosulfonic acid (PFSA) ionomer monolayers at the air/water interface. Equipped with a custom-designed double wall knife-edge interfacial rheometer, we measure both the linear and nonlinear viscoelasticity of various PFSA ionomer monolayers. Based on rheological measurements along with other static measurements, we find that the rheological properties of the PFSA ionomer monolayers mainly originate from the electrostatic interaction of negatively charged groups (SO3−) rather than direct interactions between backbones, as is typical of other polymeric monolayers. Although the rheological properties mainly come from the SO3− groups, equivalent weight (EW) and length of the side chain affect the rheological properties as well: (1) surface activity increases with EW, thereby a larger EW tends to have stiffer interfaces; (2) PFSA ionomer with longer side chains also has larger shear moduli at the same surface pressure (Π), presumably because the longer side chain has larger configurational entropy, thus leading to better closed packing. Moreover, it is found from Π dependent measurements that both the elastic and viscous moduli exhibit unusually weak dependence on Π compared with typical polymeric and surfactant monolayers. The weak Π dependence can be explained in terms of charged colloids with long-range repulsive interactions, as they are susceptible to shear stress but resistive to compressional stress. This rheology of ionomers and their underlying morphology at the interface are expected to provide useful information for various membrane applications where ultrathin membranes can be helpful, such as ion exchange membranes and fuel cell/flow battery membranes. [ABSTRACT FROM AUTHOR]

This article presents a strategy to develop the porous fabric‐hydrogel composite membranes (PFHCMs) with high nitrate ion (NO3−, a source of a main nutrient, nitrogen) permeability and sufficient mechanical strength required for microalgal cultivation in the ocean. The porous structure in the PFHCMs is generated by using three different types of porogens: water‐soluble macromolecules, surfactant micelles, and CaCO3 microparticles. Various PFHCMs, composed mainly of poly(hydroxyethyl methacrylate) hydrogels and cotton fabric, are prepared with varying the content of monomer, initiator, and crosslinker and the type and content of porogen. Their morphological, physical, and mechanical properties are characterized for variables. Among three porogens, the surfactant micelles with a large enough amount produce the optimal PFHCMs with NO3− ion permeability coefficient (5.49 × 10−8 m2 min−1, approximately 5 and 20 times higher than those of the fabric‐hydrogel composite membranes, synthesized without any porogen in a previous work, and the commercial cellulose acetate membranes, respectively). Their mechanical strength (i.e., the ultimate stress is 9.37 MPa) is high enough for practical uses. Therefore, these PFHCMs are good candidate membranes in microalgal cultivation for biorefinery and other biomedical applications, including wound dressings. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48324. [ABSTRACT FROM AUTHOR]