Research Focus
What are Colloids?
Our research is centered around colloids. In our daily life, colloids are an always-present but invisible companion. We will find them in what we eat (butter, mayonnaise, salad dressings, ice cream), in what we drink (milk, foam on beer or coffee), on what we wear (textiles, shoes), on what we sit or sleep (chairs, sofas, mattresses), in our cosmetic products (creams, toothpaste, body lotions, hair - spray), as paints on our walls, and on the paper on which we wish to w rite or print our ideas. Colloids include nanoparticles, gels, sols, emulsions, aerosols, and foams. Colloidal objects have dimensions in a range between 1 nm and 1000 nm: That's why they do not settle; they diffuse through the media, which keeps them in dispersion. They strongly scatter light. It is for this reason that milk or clouds look opaque. Due to their fascinating properties and the wide range of practical applications, colloid chemists are the key to success in diverse industries, including global chemical companies, the food industry and papermaking industry, just to name a few. A fundamental understanding of colloids, their fabrication, stabilization, modification and handling is thus highly relevant.
What we do with Colloids
Our ambition is to further extend the range of colloids by fabricating new tailored-made colloidal structures. In this context, we are working on assemblies of colloidal particles (either polymer colloids or inorganic nanoparticles). The concept behind our projects is to build structures that are not accessible by conventional protocols. Minimization of surface tension, for example, favors the formation of spherical shapes. Packing colloidal particles into clusters of a small number of individual particles can result in a variety of non -spherical geometries. This class of supraparticles is often referred to as "colloidal molecules" because they exhibit symmetries that are reminiscent to true molecules. Due to their complex but defined geometries, "colloidal molecules" are ideal model systems to study properties of particles with complex shapes (e.g. Brownian diffusion). Moreover, exciting physical properties may emerge by packing nanoparticles into supraparticles. One example is the formation of intense plasmonic hotspots in clusters of gold nanoparticles. Efforts with regard to a fabrication of "colloidal molecules" in sufficient scales are still necessary to exploit their full potential. Apart from the actual preparation, this is equally valid for the subsequent fractionation of the supracolloids. "Colloidal molecules" are particularly promising with regard to innovative applications that demand materials with specific symmetries or functionality. The anisotropic nature may enable their directed assembly into the next higher level of hierarchically organized materials.
Please visit our project pages for further information.