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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 51: Complex Fluids and Soft Matter (joint session DY/CPP)

CPP 51.8: Talk

Friday, March 22, 2024, 11:30–11:45, BH-N 243

Thermofluidic Non-equilibrium assembly of Functional Structures — •Desmond Quinn, Diptabrata Paul, and Frank Cichos — Molecular Nanophotonics Group, Peter Debye Institute for Soft Matter Physics, Leipzig University, 04103 Leipzig

Assembly in equilibrium is dictated by static energy landscapes. Non-equilibrium assembly on the other hand is driven by fluxes that can be controlled by external energy inputs, enabling reconfigurable structures. The non-equilibrium assembly of colloids was explored here, which was mediated by optically driven heat dissipation. The heat dissipated leads to thermofluidic flows and osmotic pressures that drive the colloidal particle towards the heated regions and lead to the formation of ordered structures.

The mechanisms of assembly were disentangled, and the growth dynamics of the structures was modeled. 3D structures were found to assembly in a matter of a few minutes, and the growth dynamics was found to be dependent on the particle fluxes. Analysis of the structure revealed its crystallinity. The emergent photonic properties of such colloidal crystal structures were investigated. A photonic stopband was observed and fit well with theoretical expectations. Furthermore, the photonic property could be modulated by modulating the assembled structure. This shows that non-equilibrium processes could be useful in assembly of reconfigurable functional materials. The manipulation of bacteria was also explored, which is useful to study bacterial interactions.

Keywords: Non-equilibrium assembly; Hydrodynamics; Depletion; Photonic crystals; Bacteria