Polyelectrolyte multilayer formation: Electrostatics and short-range interactions
School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 69978, Tel Aviv, Israel
Published online: 21 February 2006
Abstract.: We investigate the phenomenon of multilayer formation via layer-by-layer deposition of alternating charged polyelectrolytes. Using mean-field theory, we find that a strong short-range attraction between the two types of polymer chains is essential for the formation of multilayers. For strong enough short-range attraction, the adsorbed amount per layer increases (after an initial decrease), and finally it stabilizes in the form of a polyelectrolyte multilayer that can be repeated hundreds of times. For weak short-range attraction between any two adjacent layers, the adsorbed amount (per added layer) decays as the distance from the surface increases, until the chains stop adsorbing altogether. The dependence of the threshold value of the short-range attraction as function of the polymer charge fraction and salt concentration is calculated.
PACS: 82.35.Gh Polymers on surfaces; adhesion – / 82.35.Rs Polyelectrolytes – / 61.41.+e Polymers, elastomers, and plastics –
© EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2006