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Title: Phase diagram of a reentrant gel of patchy particles

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.
Authors:
; ;  [1] ;  [2]
  1. Department of Physics, Sapienza, Università di Roma, Piazzale Aldo Moro 2, I-00185 Roma (Italy)
  2. Laboratoire Charles Coulomb, UMR 5221, CNRS and Université Montpellier 2, 34095 Montpellier (France)
Publication Date:
OSTI Identifier:
22253242
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 24; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BINARY MIXTURES; DENSITY; FLUIDS; GELS; MOLECULAR DYNAMICS METHOD; MONTE CARLO METHOD; PHASE DIAGRAMS; RELAXATION; SIMULATION; STABILITY; TEMPERATURE DEPENDENCE; THERMODYNAMICS