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arXiv · 1310.3730

Phase Diagram of a Reentrant Gel of Patchy Particles

Sándalo Roldán-Vargas·Frank Smallenburg·Walter Kob·Francesco Sciortino
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Abstract

We study the phase diagram of a binary mixture of patchy particles which has been designed to form a reversible gel. For this we perform Monte Carlo and molecular dynamics simulations to investigate the thermodynamics of such a system and compare our numerical results with predictions based on the analytical parameter-free Wertheim theory. We explore a wide range of the temperature-density-composition space that defines the three-dimensional phase diagram of the system. As a result, we delimit the region of thermodynamic stability of the fluid. We find that for a large region of the phase diagram the Wertheim theory is able to give a quantitative description of the system. For higher densities our simulations show that the system is crystallizing into a BCC structure. Finally we study the relaxation dynamics of the system by means of the density and temperature dependences of the diffusion coefficient. We show that there exists a density range where the system passes reversibly from a gel to a fluid upon both heating and cooling, encountering neither demixing nor phase separation.

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Sándalo Roldán-Vargas, Frank Smallenburg, Walter Kob, Francesco Sciortino. 2013-12-16. Phase Diagram of a Reentrant Gel of Patchy Particles. https://doi.org/10.1063/1.4849115

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