Self-organization of anisotropic and binary colloids in thermo-switchable 1D microconfinement

Abstract

Anisotropic and binary colloids self-assemble into a variety of novel supracolloidal structures within the thermo-switchable confinement of molecular microtubes, achieving structuring at multiple length scales and dimensionalities. The multistage self-assembly strategy involving hard colloidal particles and a soft supramolecular template is generic for colloids with different geometries and materials as well as their binary mixtures. The colloidal architectures can be controlled by colloid shape, size, and concentration. Colloidal cubes align in chains with face-to-face arrangement, whereas rod-like colloids predominantly self-organize in end-to-end configurations with their long axis parallel with the long axis of the microtubes. The 1D microconfinement imposed on binary mixtures of anisotropic and isotropic colloids further increases the diversity of colloid-in-tube structures. In cube-sphere mixtures, cubes may act as additional confiners, locking in colloidal sphere chains, while a "colloidal Morse code" is generated where rods and spheres alternate in the case of rod-sphere mixtures. The versatile confined colloidal superstructures including their thermoresponsive assembly and disassembly are relevant for the development of stimulus-responsive materials where controlled release and encapsulation are desired. The hierarchical self-assembly of shape-anisotropic colloids and their binary mixtures with isotropic colloids in 1D microconfinement yields a rich variety of novel supracolloidal architectures. The thermo-switchable co-assembly of molecular microtubes and colloidal superstructures is generic for colloids with different geometries, materials, and sizes and may open new routes for controlled release, encapsulation, and data storage applications.