Recent Progress on Preparation of Anisotropic Block Copolymer Particles Self-Assembled in 3D Emulsion Droplets

Self-assembly of block copolymers (BCPs) into anisotropic colloidal particles within 3D emulsion droplets has attracted considerable interest since the confined assembly in deformable geometries offers significant potential for designing and constructing specific anisotropic polymer materials for various applications. By precisely controlling the deformation of emulsion droplets, nucleation, and deposition sequence of BCP segments at the oil/water interface, various anisotropic polymer assembly particles with tunable shapes and internal structures can be generated. This review summarizes the recent advancements in the design and formation of anisotropic polymer assembly particles via confined assembly of BCPs, including an overview of emulsification techniques and methods, the regulation of particle shapes and internal structures, as well as the diverse applications of resulting anisotropic particles. Typically, the regulation of anisotropic shapes can be achieved through experimental approaches, such as the volume ratio and interactions between blocks, surfactant selectivity, crystallization-induced deformation, stimuli-responsive additives, evaporation rate, post-annealing, confinement degree, and disassembly of prepared polymer colloids. Finally, the further perspectives and challenges in the construction anisotropic functional polymer materials are discussed.