title: Phase diagram of a reentrant gel of patchy particles.
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.
authors.affiliation: Department of Physics, Sapienza, Università di Roma, Piazzale Aldo Moro 2, I-00185 Roma, Italy.
authors.forename: Sándalo
authors.initials: S
authors.lastname: Roldán-Vargas
authors.affiliation: Department of Physics, Sapienza, Università di Roma, Piazzale Aldo Moro 2, I-00185 Roma, Italy.
authors.forename: Frank
authors.initials: F
authors.lastname: Smallenburg
authors.affiliation: Laboratoire Charles Coulomb, UMR 5221, CNRS and Université Montpellier 2, 34095 Montpellier, France.
authors.forename: Walter
authors.initials: W
authors.lastname: Kob
authors.affiliation: Department of Physics, Sapienza, Università di Roma, Piazzale Aldo Moro 2, I-00185 Roma, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Sciortino