(697d) A Unified Morphological Model for Ionomers with Ordered Aggregate Structures

This talk describes what the author believes to be the underlying structural makeup of ionomers with an ordered (i.e. where the anions and cations have a regular repeating structure) aggregate structure. The author presents evidence from a variety of techniques, primarily his own EXAFS work and the electron microscopy work of Winey et.al., suggesting that the fundamental structure of aggregates is planar, and that these planes can show curvature and therefore adopt morphologies that are tubular or even spherical in appearance. The key consideration of any model is that an allowance must be made for the placement of polymer chains, and a planar model is a straightforward accomplishment of that. Curvature can allow for a significant reduction of the number of atoms at edges; and edge atoms are expected to be extremely energetically unfavorable. How such a model is consistent with observations from scattering will also be discussed, and how polar plasticizers (e.g. water) can affect this structure. Finally, the author will briefly speculate about characteristics of ionomers with unordered aggregate structures.