Lewis Adduct Binding-Induced Bond Polarization in Polymer Solutions to Drive Micelle and Vesicle Formation

Driving self-assembly through non-covalent interactions to create nanostructured materials is a key feature of supramolecular chemistry, yet the connection between molecular-level changes and larger-scale organization is still unknown. Here, we propose the concept of Lewis adduct binding-induced bond polarization where the formation of the Lewis adduct leads to a large dipole, significantly altering the intermolecular interactions between different species and inducing self-assembly. Specifically, a diblock copolymer, poly(2-(dimethylamino)ethyl methacrylate)-b-polystyrene (PDMAEMA-b-PS), self-assembles into nanostructured colloidal aggregates (e.g., spherical micelles and vesicles, which is controlled by the poly(Lewis base) block fraction) on addition of the Lewis acid tris(pentafluorophenyl) borane (BCF) while in toluene. The degree of bond polarization of the Lewis adduct was quantified by measuring the dielectric constant of adduct mixtures and was confirmed through density functional theory. Binding-induced bond polarization has far ranging implications in supramolecular systems where the formation if dipoles result from non-covalent, intermolecular interactions.