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Shin, Dong Won,Lee, So Young,Lee, Chang Hyun,Lee, Kwan-Soo,Park, Chi Hoon,McGrath, James E.,Zhang, Mingqiang,Moore, Robert B.,Lingwood, Mark D.,Madsen, Louis A.,Kim, Young Taek,Hwang, Inchul,Lee, Youn American Chemical Society 2013 Macromolecules Vol.46 No.19
<P>Ordered morphologies in disulfonated poly(arylene sulfide sulfone nitrile) (SPSN) copolymers were generated via thermal annealing followed by multiblock copolymer synthesis. While SPSN random copolymers (R-SPSN) showed featureless morphologies, the SPSN multiblock copolymers (B-SPSN) exhibited cocontinuous lamellar morphologies with a center-to-center interdomain size of up to 40 nm. In spite of the well-ordered, interconnected hydrophilic domains, the water self-diffusion coefficient (e.g., <I>D</I> = (0.7–2.0) × 10<SUP>–10</SUP> m<SUP>2</SUP> s<SUP>–1</SUP>) and proton conductivity (e.g., σ = 0.16–0.20 S cm<SUP>–1</SUP> in deionized water at 30 °C) through B-SPSN were lower than those of the corresponding R-SPSN (e.g., <I>D</I> = (3.5–3.9) × 10<SUP>–10</SUP> m<SUP>2</SUP> s<SUP>–1</SUP> and σ = 0.21 S cm<SUP>–1</SUP>) due to the relatively lower water uptake of the B-SPSN after thermal annealing. The reduced water uptake of B-SPSN was beneficial to reduction of peroxide degradation rate. Thermal annealing produced significant gains in morphological ordering and finer control over desired membrane properties for proton conduction applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2013/mamobx.2013.46.issue-19/ma400889t/production/images/medium/ma-2013-00889t_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma400889t'>ACS Electronic Supporting Info</A></P>
Linear coupling of alignment with transport in a polymer electrolyte membrane
Li, Jing,Park, Jong Keun,Moore, Robert B.,Madsen, Louis A. Nature Publishing Group 2011 NATURE MATERIALS Vol.10 No.7
Polymer electrolyte membranes (PEMs) selectively transport ions and polar molecules in a robust yet formable solid support. Tailored PEMs allow for devices such as solid-state batteries,??artificial muscle?? actuators and reverse-osmosis water purifiers. Understanding how PEM structure and morphology relate to mobile species transport presents a challenge for designing next-generation materials. Material length scales from subnanometre to 1??關m (refs?, ) influence bulk properties such as ion conductivity and water transport. Here we employ multi-axis pulsed-field-gradient NMR (ref.?) to measure diffusion anisotropy, and <SUP>2</SUP>H NMR spectroscopy and synchrotron small-angle X-ray scattering to probe orientational order as a function of water content and of membrane stretching. Strikingly, transport anisotropy linearly depends on the degree of alignment, signifying that membrane stretching affects neither the nanometre-scale channel dimensions nor the defect structure,causing only domain reorientation. The observed reorientation of anisotropic domains without perturbation of the inherent nematic-like domain character parallels the behaviour of nematic elastomers, promises tailored membrane conduction and potentially allows understanding of tunable shape-memory effects in PEM materials. This quantitative understanding will drive PEM design efforts towardsoptimal membrane transport, thus enabling more efficient polymeric batteries, fuel cells, mechanical actuators and water purification.