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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 58: Fluids and Interfaces II

CPP 58.3: Vortrag

Donnerstag, 23. März 2017, 10:45–11:00, ZEU 255

Deriving interaction potentials to simulate self-assembly of graphene particles at the oil-water interface — •Vikram Reddy Ardham and Frédéric Leroy — Eduard-Zintl-Institut für Anorganische und Physikalische Chemie,TU Darmstadt

High interfacial tension between immiscible liquids can provide necessary driving force for the self-assembly of nano-particles at the interface. Particularly, water-oil interfaces have been exploited to synthesize networks of highly inter-connected graphene flakes of only up to a few layers thick. To simulate and study these systems, we derive coarse-grained (CG) force-fields for particle-liquid interactions. CG potentials derived using the standard approaches often give rise to free energies far from the reference system and might not lead to any self-assembly at the interface, since the entire process is possible only within a narrow window of interfacial free energies determined by the wetting coefficient (ω) [Polym. Bull. 1991, 25 (2), 265-271]. Therefore, we derive CG particle-liquid interaction potentials [J. Chem. Phys. 2015, 143 (24)] to get the right free energy balance and therefore the right 'ω'. The derived coarse-grained potentials provide accelerated dynamics of up to a few orders of magnitude without losing the thermodynamic or much of the structural information. Further, we illustrate the applicability of method by simulating a relatively large water-oil interface with graphene particles forming an inter-connected network using the derived coarse-grain model. The method might find applications in multi-scale modeling of polymer nano-composites where a great deal of solid-liquid interface is to be modelled accurately.