Temperature-responsive supramolecular assembly and morphology of arborescent copolymer micelles with a solvophilic core-solvophobic shell structure

This paper describes the supramolecular assembly of arborescent (dendrigraft) copolymers in solution. The dendritic copolymers remained as unimolecular (nonassociated) micelles in toluene at temperatures above the critical self-assembly temperature (est) but aggregated into supramolecular structures with a diameter of a few micrometers below the est. Small-angle neutron scattering (SANS) measurements in toluene revealed that the P2VP shell of the unimolecular micelles was swollen above the est. The supramolecular aggregates obtained below the est had a spherical topology and a relatively uniform size according to electron microscopy analysis. The temperature- responsive self-assembly process was fully reversible. The est varied with the copolymer concentration and shifted to higher temperatures as the length of the P2VP chains in the shell increased. The self-assembly mechanism reported provides a path to new types of "smart" supramolecular structures.