Confinement Assembly of Terpolymer-Based Janus Nanoparticles

While the confinement assembly of block copolymers into functional microparticles has been extensively studied, little is known about the behavior of Janus nanoparticles (JNPs) in spherical confinement. Here, the confinement self-assembly of JNPs in drying emulsion droplets is investigated and their behavior compared to their ABC triblock terpolymer precursors. Emulsions of both materials are prepared using Shirasu Porous Glass membranes leading to narrow size distributions of the microparticles with average hydrodynamic radii in the range of R_h  = 250-500 nm (depending on the membrane pore radius, R_pore ). The internal structure of the microparticles is verified with transmission electron microscopy (TEM) on ultrathin cross sections and compared to the corresponding bulk morphologies. While the confinement assembly of terpolymers results in microparticles with ordered inner morphologies, order for JNPs diminishes when the Janus balance deviates from parity.