Molecular Dynamics Simulations of Multilayer Polyelectrolyte Films:  Effect of Electrostatic and Short-Range Interactions

Abstract

The effect of the strength of electrostatic and short-range interactions on the multilayer assembly of oppositely charged polyelectrolytes at a charged substrate was studied by molecular dynamics simulations. The multilayer buildup was achieved through sequential adsorption of charged polymers in a layer-by-layer fashion from dilute polyelectrolyte solutions. The strong electrostatic attraction between oppositely charged polyelectrolytes at each deposition step is a driving force behind the multilayer growth. Our simulations have shown that a charge reversal after each deposition step is critical for steady multilayer growth and that there is a linear increase in polymer surface coverage after the first few deposition steps. Furthermore, there is substantial intermixing between chains adsorbed during different deposition steps. We show that the polymer surface coverage and multilayer structure are each strongly influenced by the strength of electrostatic and short-range interactions.

Electrostatics in soft matter

“…Later Panchagnula et al performed similar computer simulations [137], where the dynamical aspect was more emphasized. Several types of substrate geometry were considered, from spherical particles [91,137,138] to planar substrates [139,140] via cylindrical ones [141]. Relevant simulation findings for spherical [91] and planar substrates [139] are going to be described.…”

“…5.3.2. Planar substrates PE multilayering onto planar substrates were investigated in [139,142,140]. The zero-curvature case differs qualitatively from the spherical one.…”

Novel food grade dispersants: Review of recent progress

“…In the last ten years or so there have also been several attempts to study the kinetics of multilayer films, as they are built up and then evolve further, by using molecular dynamic simulations [28,29]. Some of these studies show clear evidence that the boundaries between different sublayers become increasingly more "fuzzy" as different biopolymers diffuse and interpenetrate each other with time.…”

“…Fig. 2 forces need to be assumed a priori and be included in order to generate stacks of sublayers on top of each other [29]. Without them the simulation will not produce more than two sublayers.…”

Interactions between casein layers adsorbed on hydrophobic surfaces from self consistent field theory: κ-casein versus para-κ-casein

“…The study also provided an explanation of the reversal of the interfacial charge during the deposition of polysaccharide, in absence of any specific short ranged interactions between protein and polysaccharide, hitherto thought to be essential in formation of such multi-layers (Patel, Jeon, Mather, & Dobrynin, 2006). Self consistent field calculations have also been applied to non-food related proteins such as neurofilament proteins (Zhulina & Leermakers, 2007).…”