Wang, Ying Gao, Jianwei Dingemans, Theo J. Madsen, Louis A. Molecular Alignment and Ion Transport in Rigid Rod Polyelectrolyte Solutions Combining molecular alignment with selective ion transport can increase the freedom to design ion-conducting polymeric materials and thus enhance applications such as battery electrolytes, fuel cells, and water purification. Here we employ pulsed-field-gradient (PFG) NMR diffusometry, <sup>2</sup>H NMR spectroscopy, polarized optical microscopy, and small-angle X-ray scattering to determine relations between counterion transport, dynamic coupling of water, and molecular alignment in aqueous solutions of a rigid rod sulfonated-aramid polyelectrolyte: poly­(2,2′-disulfonyl-4,4′-benzidine terephthalamide) (PBDT). <sup>23</sup>Na PFG NMR on PBDT solutions and simple sodium salt solutions shows significantly slower Na<sup>+</sup> counterion diffusion in PBDT, providing agreement between counterion condensation theory and quantitative transport information. Strikingly, from <sup>2</sup>H NMR spectroscopy we observe that the orientational order parameter of partially aligned solvent D<sub>2</sub>O molecules increases linearly with polymer weight percentage over a large concentration range (1.4 to 20 wt %), while the polymer chains possess essentially a large and fixed order parameter <i>S</i><sub>matrix</sub> = 0.76 as observed using both SAXS and <sup>2</sup>H NMR on labeled polymers. Finally, we apply a two-state model of water dynamics and a physical lattice model to quantitatively relate D<sub>2</sub>O spectral splittings and nematic rod–rod distance. These studies promise to open new pathways to understand a range of anisotropic polymer systems including aligned polymer electrolyte membranes, wood composites, aligned hydrogels, liquid crystals, and stretched elastomers. counterion transport;transport information;fuel cells;alignment;D 2O;counterion diffusion;anisotropic polymer systems;2 H NMR spectroscopy;battery electrolytes;lattice model;23 Na PFG NMR;NMR diffusometry;wood composites;2 H NMR;SAXS;order parameter Smatrix;orientational order parameter;PBDT solutions;polymer electrolyte membranes;studies promise;ion transport;counterion condensation theory;polymer weight percentage;water purification;D 2O molecules increases;Ion Transport;Molecular Alignment;Rigid Rod Polyelectrolyte SolutionsCombining;water dynamics;sodium salt solutions;polymer chains 2014-05-13
    https://acs.figshare.com/articles/journal_contribution/Molecular_Alignment_and_Ion_Transport_in_Rigid_Rod_Polyelectrolyte_Solutions/2298202
10.1021/ma500364t.s001