Non-equilibrium properties of complex matter: From hydrodynamics to particle properties
Tuesday, November 19, 2019
3:30PM – 5PM
POB 6.304

Monica E. A. Zakhari

Complex matter form an ideal platform for to the design and control of new material with improved functionality. The versatility to tailor the overall properties via (i) the individual particle properties and (ii) the properties of the suspending media makes them ubiquitous to various biological and industrial applications, e.g. food, cosmetics, paints, and pharmaceuticals. The properties of the constituent particles can vary from hard-elastic- viscoelastic, owing to the internal structure of the particle, while the solvent-mediated interactions modulate their dynamics. In this talk, I will show, using dynamic simulations and multi-scale modeling, how the internal structure of the individual particle and the hydrodynamic interactions with the suspending solvent induce arrested transitions.

I will show the importance of the many-body hydrodynamic interactions and lubrications forces on both the equilibrium and non-equilibrium solidification processes of hard particle suspensions, i.e. crystallization and vitrification, respectively, utilizing large-scale Stokesian dynamics simulation. Jumps from liquid into the solid region are executed via controlled volume-fraction, where the speed of the quench permits toggling between equilibrium and arrested states. The relative influence of many-particle hydrodynamics on aging and crystallization dynamics is studied, and I elucidate the influence of the quenching process on long-time fate of the material. I will also outline the two-scale dynamic model developed to effectively model the size- and shape-dynamics of particles that originate from their internal structure.

Using non-equilibrium thermodynamics, the macroscopic fluid-dynamics and the particle dynamics on the particle level are mutually coupled in a consistent manner, establishing the link between the macroscopic behavior, e.g. stresses, and the dynamics of the microstructure, e.g. particle shape and size. The model is cast into a form that enables modelling particles with both shape-preserving size-changes (e.g. swellable particles) and volume-preserving shape-changes (e.g. incompressible yet deformable particles). The size- shape model distinguishes itself in unifying prior knowledge of purely-shape models with that of purely-size models by appropriate choices of the Helmholtz free energy and the generalized mobility.

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