Structure and mechanism of formation of polyelectrolyte multilayers

The mechanism of formation and structure of polyelectrolyte multilayers deposited from salt free solutions on a charged substrate was investigated using MD simulation. The minimum energy configuration of the system was investigated by varying the temperature of deposition and lowering the charge of monomers in the polyelectrolyte chains. The PE molecules in the multilayers were found to be kinetically trapped under influence of strong electrostatic interactions. The multilayered structure composed of seven double layers contained many voids and imperfections resulting from freezing of the structure. Simulation results also show that the resulting structure is truly layered and that the layer thickness is not very different from the thermodynamic equilibrium layer thickness. The structure of the layers is fuzzy in nature and molecules show a high level of interpenetration and disorder.