Supracolloidal self-assembly
Our aim is to synthesize and analyze organic nanoparticles with defined shapes and surfaces in terms of chemical patterns (patches) and 3D surface asperities (topography). We develop concepts to design such nanoparticles and seek to understand how shape and surface pattern affect interparticle interaction, their recognition at interfaces, and their ability to assemble into supracolloidal lattices.
To form patchy and topographic nanoparticles, we synthesize block copolymers with predefined chemistry and length, and self-assemble these polymers into multicompartment nano- or microparticles. Janus nanoparticles are the simplest case of patchy particle where the surface is strictly separated into two hemispheres with different chemistry (by choice of the polymer blocks). These particles show directional interactions and are studied for their assembly into supracolloidal clusters and monolayers at interfaces (colloidal surfactant). We developed a method for the synthesis of a variety of new Janus shapes including Janus rings, cups, and discs. Topographic patterns are the 3D extension of directional surface patterns and provide specific anchoring sites to attach luminescent bioprobes and biomolecules or receptors for recognition, and find application as platform technology for nanomedicine. We seek to realize high specificity on the nanoparticle surface, which requires precision patterning with few-nanometer resolution. We currently investigate this concept of lock and key nanoparticles for the formation of colloidal lattices with defined porosity, and ultimately, photonic band gaps.
