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Preparing AEMs with robust mechanical properties, high ionic conductivity and excellent chemical stability is challenging. Here, cross-linked/aggregated AEMs are prepared by incorporating hydrophilic Jeffamine cross-linkers and hydrophobic side chains into the rigid quaternized poly (vinyl benzyl chloride). Jeffamine's flexibility ensures high elongation at break of the cross-linked/aggregated membranes (125.0–199.8%). The hydrophobic side chain limits excessive water absorption and facilitates self-aggregation of hydrophilic and hydrophobic domains, enhancing tensile strength (5.08–7.40 Mpa in wet state) and improving ionic conductivity of the AEMs (73.8–110.4 mS cm−1 at 80 °C). Alkali-resistant PVB, restricted dimensionality, and ordered micro-phase separation morphology contribute to outstanding chemical stability of the AEMs. Degradation of both backbones and cations is <20% after treatment in 1 M NaOH solution at 80 °C for 30 days. Based on the membrane, a peak power density of 354.4 mW cm−2 at 60 °C is yielded. PVB based AEMs of c (Je) a Cx-QAPVB exhibit excellent flexibility, outstanding alkali-resistant and high hydroxide ion conductivity. [Display omitted] • Highly flexible and transparent poly (vinyl benzyl chloride) based anion exchange membranes are prepared. • Anion exchange membranes exhibit improved ionic conductivity and robust stability. • A peak power density of 354.4 mW cm−2 is presented. [ABSTRACT FROM AUTHOR]

Electrolyzing water is an environmentally friendly and renewable way to obtain high purity hydrogen. Ruthenium has strong water dissociation ability and suitable hydrogen adsorption energy, so it is considered as one of the candidates of excellent electrocatalysts for hydrogen evolution in alkaline solution. The dynamic hydrogen bubble template (DHBT) is a good electrodeposition technology, which can obtain the 3D metal foams. However, as far as we know, there is no report on the preparation of Ru electrocatalyst by the DBHT method. In this work, the trumpet-shaped Ru on amorphous cobalt support (T-Ru/a-Co) is prepared by the DHBT electrodeposition for the first time. The defect locations are uniformly distributed on the surface of amorphous cobalt (a-Co), which can effectively lead to the formation of nano-bubble template in the DHBT process. However, this special morphology cannot be obtained on the surface of crystalline Co (c-Co). In addition, the electronic structure of T-Ru/a-Co has also been obviously modified, in which the proportion of Ru4+/Ru0 in T-Ru/a-Co has increased, accompanied by the change of binding energy of Ru. It only needs an overpotential of 49 mV to obtain a current density of 10 mA cm−2 for the T-Ru/a-Co. The specific activity (SA), turnover frequency (TOF) and mass activity (MA) of T-Ru/a-Co are 0.23 mA cm−2, 0.48 s−1 and 0.24 A mg−1, which are both higher than those of Pt/C, the disk-shaped Ru on the c-Co support (D-Ru/c-Co) and Ru/C, respectively. • The trumpet-shaped Ru is prepared by the dynamic hydrogen bubble template (DHBT) electrodeposition for the first time. • The amorphous Co can form nano-bubble template in DHBT process, but it can't be realized on the surface of crystalline Co. • The electronic structure of trumpet-shaped Ru has also been obviously modified. • The specific activity, turnover frequency and mass activity of trumpet-shaped Ru are both higher than those of Pt/C. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, dynamic mechanical analysis (DMA), dielectric spectroscopy (DS) and positron annihilation lifetime spectroscopy (PALS) were used to study chlorinated butyl rubber (CIIR), in order to shed light on its unique relaxation behaviors. The dynamic mechanical loss tangent of CIIR reveals an asymmetrical broad structure with a maximum peak on the high-temperature side and a shoulder peak on the low-temperature side. DS clarifies that the shoulder peak, which exactly corresponds to the ɛ″ peak, is the α process originating from the local segmental motion. While the maximum peak is assigned to the slow process arising from the motion of longer chain segments. The slow process exhibits stronger frequency dependence than the α process. The PALS analysis also shows the two processes; moreover, it suggests that CIIR exhibits very effective chain packing. It is due to the effective chain packing that the motion of longer chain segments is retarded and separates from the local segmental motion in time scale. This effect is another reason for the two-peak structure of CIIR, besides the low intermolecular co-operativity. [Copyright &y& Elsevier]

In order to achieve a better trade-off among ionic conductivity, mechanical strength and chemical stability, a series of novel aggregated and ionic cross-linked anion exchange membranes (AEMs) are recommended, namely, ac S 6 QAPSF, ac S 8 QAPSF and ac S 10 QAPSF. Cross-linked network shoulders the responsibility to toughen the ac S x QAPSF. Appropriate micro-morphology is responsible for facilitating the conduction of OH− and improving the alkaline stability of the ac S x QAPSF. Compared with the original QAPSF, ac S x QAPSF membranes exhibit much better properties. Specifically, for ac S 8 QAPSF, a high OH− conductivity of 90.5 mS cm−1 is achieved at 80 °C, with the swelling degree of 10.0%. The tensile strength and elongation at break of wet ac S 8 QAPSF at 25 °C are 23.9 Mpa and 21.1%, respectively. After testing in 1 M NaOH at 80 °C for 30 days, the weight loss of ac S 8 QAPSF is 8.0%, with the losses of tensile strength and elongation at break of 13.8% and 13.3%, respectively. Its IEC and IC retentions are 92.0% and 90.5%, respectively. For ac S 8 QAPSF, a fuel cell peak power density of 0.612 W cm−2 is obtained at 60 °C. While for QAPSF, its fuel cell peak power density is only 0.101 W cm−2, and the film is cracked after the 30 days stability test. The unique ac S x QAPSF membrane can alleviate the tradeoff among ionic conductivity, mechanical strength and chemical stability. Image 1 • Novel aggregated and ionic cross-linked AEMs based on PSF are synthesized. • An important insight into the design of AEMs with high performance is provided. • The fuel cell of ac S 8 QAPSF achieved a peak power density of 612 mW cm−2 at 60 °C. [ABSTRACT FROM AUTHOR]