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Self-assembly of colloidal particles has emerged as the most promising route to create complex structures on the nano- and micron-scale. The key elements to the successful bottom-up construction of complex materials are believed to be colloids with anisotropic shapes and directional interactions. Experimental examples of self-assembling anisotropic colloids are, however, still scarce and the influence of their anisotropic shape on, for example, Brownian motion or rheology is not well understood.
In this talk, I will first present a novel approach for creating such anisotropic patchy particles by reconfiguring random aggregates of colloidal spheres. We achieve the reconfiguration into uniform configurations by swelling the polymer spheres with an apolar solvent, which enables reorganisation through minimisation of the interfacial energy. I will demonstrate that we can obtain a wide variety of anisotropic colloids by tuning the parameters of the reconfiguration. In the second part of the talk, I will discuss how the anisotropic particle shape affects the Brownian motion. We observed a wide variety of anisotropic colloidal particles with confocal microscopy and calculated the hydrodynamic friction matrix from the particle trajectories. We found that symmetries in the particle shape are well-reflected in the entries of the friction matrix. We compare our experimentally obtained results with numerical simulations and theoretical predictions.
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