Precise Associating Polymers Exhibit New Morphologies and Promising Properties.

Acid- and ion-containing polymers have specific interactions that produce both acid- or ion-rich aggregates arranged in hierarchical nanoscale morphologies and remarkable bulk properties. Untangling the correlations between the primary structure of such associating polymers and their morphologies and properties has long been a challenge in polymer physics, because most acid- and ion-containing polymers have random sequences of polar and non-polar monomeric units. New synthetic methods increasingly produce polymers with greater molecular precision that provide greater uniformity of and control over the hierarchical morphologies and even yield new morphologies. Specifically, we have studied a series of precise polyethylenes synthesized by acyclic diene metathesis (ADMET) chemistry that have functional groups evenly spaced along linear polyethylenes. We have established design rules connecting these precise polymers to particular hierarchical morphologies and have discovered a variety of new morphologies. This talk will discuss the mechanical properties of precise acid- and ion-containing polyethylenes, particularly the morphological transformations that correlated with strain hardening during tensile deformation. In addition, this talk will highlight a precise sulfonated polyethylene that exhibits well-controlled chain folding to produce a highly uniform morphology with high proton conductivity. Above 65% relative humidity at 40°C the proton conductivity through these layers is on par with Nafion 117. Finally, the talk will include comparisons between precise, nearly precise and random polymers to assess the impact of polymer microstructure.