  A new potential of mean force is proposed for colloidal dispersions, which is
obtained from coarse grained, pair interactions between colloidal particles
formed by the explicit grouping of particles that are themselves groups of
atoms and molecules. Using numerical simulations, we start by constructing
colloidal particles made up of 250 mesoscopic particles joined by springs and
interacting with each other through short range forces. Afterward we proceed to
model several colloidal concentrations and obtain the colloidal particles pair
correlation function, from which we derive the potential of mean force. In our
second case study, we add linear polymer chains of the same length that attach
by one of their ends to the colloids, at a fixed colloidal concentration, and
carry out numerical simulations at increasing concentrations of polymer chains,
from which we obtain the potential of mean force once again following the same
procedure as in the previous case. For the last case study we fixed both the
colloids and the polymer chains concentration, while increasing the length of
the polymer chains and obtain again the potential of mean force. In all of
these simulations, the solvent particles are included explicitly. Using these
data we propose a new effective potential of interaction for colloidal
dispersion whose parameters can be obtained from mesoscopic scale parameters
and carry out standard molecular dynamics simulations with this new potential,
thereby providing a route for more fundamentally obtained, coarse grained
approaches to model colloidal dispersions.
