CHARLA IFLYSIB VIRTUAL Viernes 29/04 · Alina Ciach · «Self-assembly in mixtures with competing interactions»

Título: Self-assembly in mixtures with competing interactions

Expositora: Alina Ciach. Institute of Physical Chemistry of the Polish Academy of Sciences (Warsaw, Poland)

Fecha: Viernes 29/04/2022 – 10:30 hs

Resumen:

A binary mixture of particles interacting with spherically-symmetrical potentials leading to microsegregation is studied by theory and molecular dynamics (MD) simulations. We consider spherical particles with equal diameters and volume fractions. Motivated by the mixture of oppositely charged particles with different adsorption preferences immersed in a near-critical binary solvent, we assume short-range attraction long-range repulsion for the interaction between like particles and short-range repulsion long-range attraction for the interaction between different ones. Both theory and MD simulations show coexistence of a low-density disordered phase with a high-density phase with alternating layers rich in the first and second components. In these layers, crystalline structure is present in the solid and absent in the liquid crystals that are stable at lower and higher temperature, respectively. At the phase coexistence of the disordered and ordered phases, the density and the degree of order of the ordered phase decrease with increasing temperature, up to a temperature where the theory predicts a narrow two-phase region with increasing density of both phases for increasing temperature. MD simulations show that monocrystals of the solid and liquid crystals have a prolate shape with the axis parallel to the direction of concentration oscillations, and the deviation from the spherical shape increases with increasing periodic order.

Ref.: Oksana Patsahan, Marek Litniewski and Alina Ciach. «Self-assembly in mixtures with competing interactions.» Soft Matter 17.10 (2021): 2883-2899.

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