Patterns in 2D core-softened systems: From sphere to dumbbell colloids

TPO Nogueira and JR Bordin, PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS, 605, 128048 (2022).

DOI: 10.1016/j.physa.2022.128048

In this paper we analyze the structural behavior of two species of core- softened colloids: spherical and dumbbell shaped molecules with distinct separations from almost complete overlap to no-overlap. Using NPT Molecular Dynamics simulations, we identified that spherical colloids can show ordered structures as a Low Density Triangular phase, Stripes, a Kagome lattice and a High Density Triangular phase. For dumbbells colloids the structures are strongly affected by the anisotropy. For dimers with low intramolecular distance we identified the Low Density Triangular phase, a cluster phase and side -to-side Stripes, while for the cases with intermediate distance we identified the Low Density Triangular, and stripes with distinct orientational patterns. When there is no overlap between the monomers in a dumbbell, a behavior similar to the spherical symmetric case is recovered. We show that the myriad of stripes patterns that arises by introducing anisotropy into the system adds extra competition beyond the existing competition given by the core-softened interaction potential. Our results shed some light in the complex behavior of colloids assembly and show how we can use the dumbbell anisotropy to control the assembly patterns. (C) 2022 Elsevier B.V. All rights reserved.

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