Polymer Micelles Composed of Molecular-Bottlebrush-Based Surfactants: Precisely Controlling Aggregation Number Corresponding to Polyhedral Structures.

Over the past few decades, there has been remarkable progress in the construction of self-assemblies in the field of supramolecular chemistry, such as micelles with precisely controlled and refined structures. One promising approach represents the previously proposed concept of Platonic micelles, in which the aggregation number (Nagg ) is discretized in accordance with vertexes of regular polyhedra (i.e., Platonic solids), i.e., 4, 6, 8, 12, and 20 units. Herein, attempt is made to construct Platonic polymer micelles using rigid and persistent architecture of molecular-bottlebrush-based surfactant (MBS). The structure of MBS micelles is carefully elucidated using small-angle X-ray and light scattering and analytical centrifugation measurements. This study shows that the Nagg of MBS micelles is consistent with one of the Platonic numbers when Nagg is intentionally set in the range of 4-20. In addition, some of the MBS micelles demonstrate a discontinuous change in Nagg , when the salt concentration is changed, which is an important factor in controlling micellar Nagg . This is one of the characteristic aggregation behaviors of Platonic micelles in surfactant systems, which strongly indicates the formation of Platonic micelles from macromolecular surfactants.