FIELDS GENERATED BY A ROD ADSORBED ON AN OPPOSITELY CHARGED SURFACE -THE EFFECT OF SURFACE ION MOBILITY AND DIMENSIONALITY ON SCREENING

Motivated by recent interest in the formation of DNA-surface complexes we study the effects of surface and counter-ion charges on the electr ostatic fields of charged rod-like macromolecules adsorbed on opposite ly charged surfaces. We find that the screening of the rod's fields, d ue to counter-ions and mobile surface charges, can be either exponenti al (leading to a finite-range interaction) in the case of weak chargin g or just algebraic in the case of strong surface charging. We test ou r analytical results with Monte Carlo simulations.