Browsing by Author "Jamieson, SA"

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    Small angle neutron scattering (SANS) studies on the structural evolution of pyromellitamide self-assembled gels
    (ACS Publications, 2014-10-31) Jamieson, SA; Tong, KWK; Hamilton, WA; He, L; James, M; Thordarson, P
    The kinetics of aggregation of two pyromellitamide gelators, tetrabutyl- (C4) and tetrahexyl-pyromellitamide (C6), in deuterated cyclohexane has been investigated by small angle neutron scattering (SANS) for up to 6 days. The purpose of this study was to improve our understanding of how self-assembled gels are formed. Short-term (< 3 h) time scales revealed multiple phases with the data for the tetrabutylpyromellitamide C4, indicating one-dimensional stacking and aggregation corresponding to a multifiber braided cluster arrangement that is about 35 Å in diameter. The corresponding tetrahexylpyromellitamide C6 data suggest that the C6 also forms one-dimensional stacks but that these aggregate to a thicker multifiber braided cluster that has a diameter of about 62 Å. Over a longer period of time, the radius, persistence length, and contour length all continue to increase in 6 days after cooling. These data suggest that structural changes in self-assembled gels occur over a period exceeding several days and that fairly subtle changes in the structure (e.g., tail-length) can influence the packing of molecules in self-assembled gels on the single-to-few fiber bundle stage © 2014, American Chemical Society.
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    Synthesis of per-deuterated alkyl amines for the preparation of deuterated organic pyromellitamide gelators
    (Pergamon-Elsevier Science Ltd, 2013-05-15) Yepuri, NR; Jamieson, SA; Darwish, TA; Rawal, A; Hook, JM; Thordarson, P; Holden, PJ; James, M
    A general, direct and scalable synthesis of per-deuterated alkyl amines is reported, together with their incorporation into pyromellitamides, which form self-assembled gels in cyclohexane. The deuterium labelling of these gelators allows the study of the dynamic intermolecular interactions in these materials using solid-state 2H NMR spectroscopy.© 2013, Elsevier Ltd.