Soft colloids are characterized by weak interactions of the order of the thermal energy. Their 3D-structure, assembly and properties therefore delicately depends on temperature, pressure and concentration, as well as on external forces mediated by flow, tension, electric and magnetic fields. We investigate the assembly of polymers and soft colloids into micellar, membrane, crystalline and quasi-crystalline structures.
Soft colloids most often posses a spatially well-defined core with a soft or diffuse corona. The density, volume and chemical makeup of this corona is the most important factor when it comes to structure formation. We found that spherical block copolymer micelles as well as one component nanocomposites in aqueous and non aquaous solvent with different chemical make-up but similar corona to core volume ratios can form quasi-crystalline structures upon shearing. We are investigating the principles behind the formation of these extraordinary structures and try to formulate a general theory as to why these structures develop. This in turn will enable us to willfully produce materials that form quasicrystals as opposed to the present where it often is pure chance. These investigations are mainly done with (Rheo-)SANS and (Rheo-)SAXS on samples and materials that are synthesized at the institute. To aid in our understanding and find the interesting regions in a very complex phase-space we utilize Molecular Dynamics simulation for 2D and 3D systems. The simulations are done under the premise that colloids, even if made up of hundreds or thousands of molecules, are behaving like single entities like atoms and so their interaction can be mimiced using simple pair potentials.
- S. Fischer, A. Exner, K. Zielske, J. Perlich, S. Deloudi, W. Steurer, P. Lindner, and S. Förster
Colloidal quasicrystals with 12-fold and 18-fold diffraction symmetry Proceedings of the National Academy of Sciences
Feb 2011, 108 (5) 1810-1814; DOI: 10.1073/pnas.1008695108
- H.Schoberth, H.Emmerich, M.Holzingen, M.Dulle, S. Förster, T.Gruhn,
Moleculan dynamics study of colloidal quasicrystals, Proceedings of the National Academy of Sciences Feb 2011, 108 (5) 1810-1814; Soft Matter, 2016, 12, 7644-7654