Polymeric micelles induced by interpolymer complexation.

The self-assembly of amphiphilic diblock copolymers in block selective solvents is well documented in the scientific literature. It gives rise to micelles in which the insoluble blocks form a core, which is surrounded by a corona that contains the soluble blocks. Another method to trigger micellization consists in introducing additional non-covalent interactions such as electrostatic interactions or hydrogen bonding in an initially soluble block copolymer. The non-covalent complexes that result from these interactions should be insoluble in order to induce micellization. Such insoluble complexes can be generated by mixing, in a non-selective solvent for all the individual blocks, two block copolymers or a block copolymer and a homopolymer, that contain mutually interacting blocks. This mixing process may, therefore, lead to insoluble non-covalent complexes, which further aggregate into micellar cores stabilized by the uncomplexed blocks. Such a strategy has been successfully implemented in both aqueous and non-aqueous solvents to create interesting stimuli-responsive systems, mainly using ionic interactions and hydrogen bonding. This feature article will summarize these approaches.