Stepwise self-assembly of bottlebrush random copolymers into uniform cylindrical structures

Controllable self-assembly of copolymers in solutions offers an effective tool for constructing functional nanostructures. However, achieving the stepwise assembly of copolymers in solutions remains challenging. In this study, we report the fabrication of cylindrical microstructures through the stepwise self-assembly of bottlebrush random copolymers (BBRPs) in solutions. The BBRPs were synthesized via a combination of “grafting-through” and “grafting-from” strategies. The assembly of BBRPs yielded spherical micelles in a mixture of dioxane and water, which further transformed into uniform cylindrical microstructures by dialyzing the solution against water. The cylinders could be obtained within a relatively large range of parameters, such as length ratios of hydrophilic/hydrophobic blocks, volume fractions of water, and copolymer concentrations. This work provides new insights into the assembly behavior of BBRPs and the preparation of cylindrical structures for applications in such as templated synthesis of hybrid materials.