Influence of polymer/solvent acid-base interactions on the aggregation of stereoregular PMMA

Stereoregular poly(methyl methacrylate) (PMMA) is able to form aggregates in solution. This aggregates formation depends strongly on the nature of the solvent, and occurs only with complexing solvents. The influence of the solvent type on the aggregate formation is not yet clarified. Apparently, there is no obvious relationship between the solvent polarity and the ability to induce aggregation of PMMA chains. In the present work, based on bibliographic studies, we tend to prove that the formation of aggregates depends, among other parameters, on the development of acid-base interactions between PMMA chains and the solvent molecules. As a matter of fact, the PMMA is considered as a basic polymer, and exchanges strong acid-base interactions with acidic solvents, Like chloroform, which is a non-complexing solvent. Such acid-base links prevent PMMA macromolecular chains to aggregate. On the contrary, complexing solvents exhibit a basic character, like PMMA. Therefore, the probability to develop PMMA/solvent acid-base interactions is strongly reduced. As a consequence, aggregation of PMMA chains is then favoured.