POLYELECTROLYTE SOLUTIONS BETWEEN CHARGED SURFACES

The effect of electrostatic interactions on the distribution of polyme rs in a good solvent is investigated for semi-dilute solutions contain ing charged polymers (polyelectrolytes) and small ions. A mean field a pproach is used to derive two coupled differential equations: a modifi ed Poisson-Boltzmann equation for the electrostatic potential, and a s elf-consistent field equation for the polymer order parameter. We comp are several monomer charge distributions; smeared, annealed and quench ed. The polymers are confined between two charged surfaces, and are in contact with a reservoir of polymers and electrolyte. This makes the annealed and quenched cases equivalent. Non-monotonous profiles are ob tained for the case of competing surface interactions: electrostatic a dsorption vs. short-range desorption.