Linear coupling of spherical block copolymer micelles induced by gradually depositing an insoluble component onto the core–shell interface†

As an emerging cutting-edge area, the anisotropic assembly of isotropic nanoparticles provides not only a unique but also a convenient pathway for constructing materials with novel structures and functions. However, examples of the anisotropic assembly of isotropic nanoparticles are still limited. In particular, methods that can delicately control the assembly of isotropic nanoparticles for the preparation of highly regular superstructures are seldom reported. Here, we report that, in a suspension of block copolymer micelles, gradually depositing an insoluble component to the core–shell interface of the micelles can increase the size of the insoluble core, leading to core–core coupling. When a certain amount of a common solvent is added into the suspension to make the core flexible, the core–core coupling can lead to the linear coupling of the micelles. In this case, only the two opposite ends of the core can be coupled; each micelle behaves like a monomer with two functionalities. Furthermore, the deposition can result in the ‘‘branched polymerization’’ of the same micelles and the ‘‘copolymerization’’ of different micelles. The redistribution of the shell-forming chains during the core–core coupling enhanced the protection of the uncoupled surface of the core, resulting in an anisotropic interaction between the micelles.