 
Summary: Adsorption and depletion of polyelectrolytes from charged surfaces
Adi Shafira)
and David Andelmanb)
School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences,
Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
Roland R. Netzc)
Sektion Physik, LudwigMaximiliansUniversitašt, Theresienstr. 37, 80333 Munich, Germany
Received 9 January 2003; accepted 17 April 2003
Meanfield theory and scaling arguments are presented to model polyelectrolyte adsorption from
semidilute solutions onto charged surfaces. Using numerical solutions of the meanfield equations,
we show that adsorption exists only for highly charged polyelectrolytes in low salt solutions. Simple
scaling laws for the width of the adsorbed layer and the amount of adsorbed polyelectrolyte are
obtained. In other situations the polyelectrolyte chains will deplete from the surface. For fixed
surface potential conditions, the salt concentration at the adsorptiondepletion crossover scales as
the product of the charged fraction of the polyelectrolyte f and the surface potential, while for a
fixed surface charge density, , it scales as 2/3
f2/3
, in agreement with singlechain results. © 2003
American Institute of Physics. DOI: 10.1063/1.1580798
I. INTRODUCTION
