Self-Assembly of block copolymers into internally ordered microparticles

Block copolymer (BCP) self-assembly is one of the most versatile concepts for the bottom-up design of functional nanostructures in materials science, nanomedicine and nanotechnology. While BCPs have been extensively studied regarding their microphase separation in bulk and the self-assembly in solution, only recently BCPs were investigated for their ability to form internally ordered microparticles. In this review, we discuss two emerging concepts: (i) the microphase separation of BCPs in the spherical confinement of evaporating emulsion droplets and (ii) the self-assembly of highly asymmetric BCPs under concentrated conditions. While the first concept yields solid and compact multicompartment microparticles suited for the synthesis of shape-anisotropic nanoparticles, photonic colloids, and actuators, the latter produces highly regular porous microparticles with exceptional interfacial area (BCP cubosomes and hexosomes). Despite distinct differences in the origin of both fields, commonalities in shape and morphology suggest an underlying formation mechanism that may link both research directions.