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arXiv · 1612.01180

Molecular organization in the twist-bend nematic phase by resonant X-ray scattering at the Se K-edge and by SAXS, WAXS and GIXRD

W. D. Stevenson·Z. Ahmed·X. B. Zeng·C. Welch·G. Ungar·G. H. Mehl
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Abstract

Using a novel Se-labelled dimer mixed with DTC5C7 aligned by magnetic field, the twist-bend nematic phase (Ntb) in dimers was studied by hard X-ray resonant scattering and by small and wide angle X-ray scattering (SAXS, WAXS). Resonant diffraction spots indicated a helix with a 9-12 nm pitch in the Ntb phase. Unprecedentedly high helix orien-tation enabled deconvolution of global and local order parameters. This, combined with simultaneous resonant and non-resonant SAXS and WAXS data, allowed us to construct a modified model of the Ntb phase matching twisted molecular conformations and the local heliconical director field.

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W. D. Stevenson, Z. Ahmed, X. B. Zeng, C. Welch, G. Ungar, G. H. Mehl. 2016-12-04. Molecular organization in the twist-bend nematic phase by resonant X-ray scattering at the Se K-edge and by SAXS, WAXS and GIXRD. https://doi.org/10.1039/c7cp01404j

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