Colloidal Self-Assembly Driven by Deformability & Near-Critical Phenomena

Abstract

Self-assembly is the spontaneous formation of patterns or structures without human intervention. This thesis aims to increase our understanding of self-assembly. In self-assembly of proteins, the building blocks are very small and complex. Consequently, grasping the basic principles that drive the formation of, for example, viruses is challenging. Colloidal particles, on the other hand, are much larger and can be used as relatively simple model particles. In this thesis, we investigate how deformability and near-critical phenomena can direct self-assembly and the formation of well-defined materials. The results in this thesis show that deformability and near-critical phenomena can take colloidal self-assembly a significant step further. Deformability allows relatively simple building blocks to self-assemble into complex structures. This enabled the first colloidal realisation of self-assembly into microcapsules without a template. Our simple building blocks are mutual attractive, anisotropic and deformable. These characteristics can also be recognized in building blocks of viruses, suggesting that these could be important in the self-assembly of virus microcapsules as well. Near-critical phenomena, on the other hand, allow for externally tunable, directional interactions. Consequently, anisotropic particles thermoreversibly self-assemble into structures that resemble micelles of molecular surfactants. We expect that externally tunable, directional interactions could facilitate self-assembly into other structures that are up till now kinetically inaccessible. Near-critical phenomena also result in thermoreversible attachment of colloids onto the surface of phase-separated droplets. We demonstrate that thermoreversible attachment can be applied to prepare and destabilize emulsions by simply changing the temperature.