Colloidal Control via Micellar Solutions

Mesoscale colloids composed of polyoctahedral silsesquioxanes (POSS) are promising candidates for the self-assembly of hierarchical structures as a continuum of size and morphology can be readily synthesized. However, there are substantial challenges in creating customized colloids that exhibit specific structural features, programmable binding, and stimuli responsiveness. Here, we explore a novel route to gain structural and directable control of these colloids by pairing them with thermoresponsive, polymeric micelles. These polymeric micelles cannot only swell the interstices of oligomeric colloidal droplets with the accuracy provided by the well-defined polymer micellization transition, but also act as absorbable colloidal depletants—a new class of depletants unrecognized by researchers until now—that can direct orientation and position. This dual functionality relies solely on the parameters of temperature and concentration, allowing for simplistic methods of control. Additionally, by selectively tuning other entropic forces at play, new opportunities to direct the transport of molecules for applications in physical and life sciences emerge.