Article,
On the bulk modulus of the cell model of charged macromolecules suspensions
J. Chem. Phys., (2003)
Abstract
We study theoretically the bulk modulus (inverse of the compressibility)
of a suspension of charged objects (macroions), making use of a cell
model to account for the finite density of macroions. The diffuse
layer of charged microspecies around a macroion is described by a
generic local density functional theory. Within this general framework,
we obtain the condition for a positive bulk modulus, which is fulfilled
by several proposals made in the literature and rules out the possibility
of a critical point. We show that a sufficient condition for a positive
compressibility also ensures that the same theory produces repulsive
effective pair potentials.
