title: Spinodal fractionation in a polydisperse square-well fluid.
abstract: Using kinetic Monte Carlo simulation, we model gas-liquid spinodal decomposition in a size-polydisperse square well fluid, representing a "near-monodisperse" colloidal dispersion. We find that fractionation (demixing) of particle sizes between the phases begins asserting itself shortly after the onset of phase ordering. Strikingly, the direction of size fractionation can be reversed by a seemingly trivial choice between two interparticle potentials which, in the monodisperse case, are identical--we rationalize this in terms of a perturbative, equilibrium theory of polydispersity. Furthermore, our quantitative results show that kinetic Monte Carlo simulation can provide detailed insight into the role of fractionation in real colloidal systems.
authors.affiliation: Soft Matter Group, School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, England, United Kingdom.
authors.forename: J J
authors.initials: JJ
authors.lastname: Williamson
authors.forename: R M L
authors.initials: RM
authors.lastname: Evans
mesh_terms: D003102:Colloids / Q000737:chemistry*; D003198:Computer Simulation; D005740:Gases / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D009010:Monte Carlo Method; D044367:Phase Transition; D012212:Rheology / Q000379:methods*
chemical_list: D003102:Colloids; D005740:Gases