1202.3982 (John J. Williamson et al.)

Spinodal fractionation in a polydisperse square well fluid    [PDF]

John J. Williamson, R. Mike L. Evans

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 metastable phases begins asserting itself shortly
after the onset of phase ordering. The direction of fractionation displays a
striking qualitative dependence on a seemingly trivial detail of the
inter-particle potential which, in the monodisperse case, would not even
constitute a distinction - we rationalise this in terms of a perturbative,
equilibrium theory of polydispersity. Furthermore, our quantitative results
show that dynamical simulation can provide detailed insight into the role of
fractionation in real colloidal systems.

View original: http://arxiv.org/abs/1202.3982