(540e) Morphological Trends in Precise Acid- and Ion-Containing Polymers

Acyclic diene metathesis (ADMET) polymerization has produced the first family of linear, high molecular weight polyethylenes precisely functionalized with acid or ionic groups. The evolutions in morphology as a function of substituent (acrylic acid, phosphonic acid, imidazolium bromide), level of functionalization (substituents every 9^th, 15^th or 21^st carbon) and polymer architecture (single or geminal substitution) is probed here by X-ray scattering at room temperature and at elevated temperatures. All materials were treated carefully to ensure equal thermal history, which is essential for the study of crystallinity. The precise copolymers result in four different morphologies at room temperature: liquid-like, layered, cylindrical and cubic. The layered morphology originates thanks to crystallinity in the linear polyethylene segments. At elevated temperatures, most materials assume a liquid-like morphology, with the morphological parameter depending on the PE spacer length and the volume fraction of pendants. The following factors were found to affect the morphology of precise copolymers: length of the segment of linear polyethylene between pendants, flexibility of the chain, volume fraction of pendants, architecture of the substituents.