Studies on growth and architecture of self-assembled multilayers fabricated from side chain azo polyelectrolytes

Growth and architecture of self-assembled multilayers, which were fabricated from four sidechain azo polyelectrolytes by a layer-by-layer adsorption technique, have been studied. The azo chromophore in side chain was employed as a "probe" to investigate chromophore orientation, desorption and nonlinear growth in the multilayer growth process. All azo polyelectrolytes showed a good self-assembling ability, but the multilayer growth processes were different from one to another. Different pH valuse resulted in the difference in multilayer growth and architecture, due to this effect on the ionization degree of the polyelectrolytes. The multilayer growth and architecture depend on the adsorption and desorption equilibrium in the systems. The end groups tethered to the azo chromophores, hydrophilic or hydrophobic, showed a significant influence on the multilayer growth. Nonlinear growth appeared at different stages of multilayer formation were found to be related to the substrates, solution properties and polyelectrolyte structures.