The deposition of charged molecules in a layer-by-layer (LbL) fashion was first reported in 1966 [1] and later rediscovered in earlier 1990s. [2] This processing approach, enabled by the long-range electrostatic attraction between oppositely charged macromolecules, is commonly used for fabrication of the molecularly layered (2-10 nm per layer) multicomponent films with a high degree of complexity (see for review [3,4]). The key to successful deposition of multilayered assemblies in a layer-by-layer fashion is the charge inversion and subsequent reconstruction of surface properties. A typical experimental procedure involves immersing a solid substrate into dilute solutions of anionic (or cationic) polyelectrolytes for an optimal period of time, followed by a rinsing step to remove any loosely adsorbed material. Continued film growth is achieved by alternating the deposition of polyanions and polycations from their aqueous solutions. After a few dipping cycles, experiments generally show a linear increase of multilayer thickness or mass, indicating that the system reaches a stationary regime. Despite of the significant progress in optimization of experimental methods utilizing the multilayer assembly the theoretical understanding of this process is still in its infancy. At this stage, molecular simulations offer a very valuable and necessary approach toward understanding the physical mechanisms of multilayer formation.
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