COLLOID STABILIZATION WITH GRAFTED POLYELECTROLYTES

We consider the structure of a surface with a fairly dense array of polyelectrolytes end-grafted to it. A simple theory for the scaling properties of the corona thickness, counterion distribution, and disjoining pressure between opposing layers in presented, which makes contact with previous numerical studies. We show that by distributing the charges on a macromolecule the interlayer force is considerably less sensitive to Debye screening by added electrolytes. This provides the physical basis for the importance of polyelectrolytes in colloid control in polar solvents. The flat layer studies are extended to the case of small (spherical) colloidal particles. Finally some speculations are made concerning the role of grafted polyelectrolytes on contributing to the bending energies of flexible membranes.