Layered polyelectrolyte complexes:: physics of formation and molecular properties

Multilayers of charged polymers can be formed by the alternating adsorption of polyanions and polycations. By this so-called layer-by-layer self-assembly method, planar surfaces or colloidal templates can be coated. This method is reviewed here with respect to the basic physical principles governing multilayer formation. Particular emphasis is put on the adsorption process of a single polyelectrolyte layer to a multilayer surface as the process controlling the charge complexation and the local molecular structure. Then, the implications for the properties of the multilayer assembly are discussed. In particular, molecular properties such as the internal stoichiometry, the local interactions, and the conformation on a molecular scale are reviewed.