High Morphological Order in a Nearly Precise Acid-Containing Polymer and Ionomer

Linear polyethylenes with functional groups at precise intervals along the backbone possess a number of remarkable properties, but the current synthetic methods that produce these precise polymers are difficult to scale up beyond the laboratory setting. When evaluating alternative synthetic routes, a critical question is how precise must the polymer microstructure be to achieve the properties of interest? As a first step in answering this question, we present morphological characterization of a <i>nearly</i> precise polymerthat is, an acid-containing polymer wherein the acid groups are separated by either <i>n</i> or <i>n</i> + 1 methylene groups. We find that the size scale and uniformity of the amorphous morphologies of the nearly precise acid-containing polymer and its sodium-neutralized ionomer are essentially indistinguishable from the precise polymers based on X-ray scattering. Meanwhile, the nearly precise polymer is strikingly distinct from a pseudorandom copolymer with similar average composition. This result suggests that the properties of nearly precise polymers could likewise be quite similar to truly precise polymers and beckons future work to explore their properties.