Polyelectrolyte multilayer formation: Electrostatics and short-range interactions

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.

Dynamic Aspects of Films Prepared by a Sequential Deposition of Species: Perspectives for Smart and Responsive Materials

“…Following these authors, their model does not apply to the low ionic strength situation where the range of the Coulombic forces is too large. Shafir and Andelman described the importance to reach sufficiently strong short range interactions between the oppositely charged polymers to obtain a regular growth of the LBL film 69…”

Theory and simulations of charged polymers: From solution properties to polymeric nanomaterials

“…The numerical solutions of the self-consistent field equations describing multilayer assembly have been recently presented by Wang [138,139] and by Shafir and Andelman [140] These calculations have shown that the sufficiently strong short-range attraction between oppositely charged polymers is essential for the formation of multilayers. The limitation of the used approach is that after completion of each deposition step the polymer density distribution of polyelectrolytes adsorbed during this deposition step was fixed for the remaining duration of the film growth process.…”

Solvent effects in polyelectrolyte adsorption: Computer simulations with explicit and implicit solvent

“…There is a large body of theoretical and computational work [16][17][18][19][20][21][22][23][24][25][26] on the adsorption of charged polymers to surfaces ͑the literature is reviewed elsewhere 9 ͒. There have been very few simulations that have focused on the effect of solvent quality on adsorption.…”