AZOCHROMOPHORE-FUNCTIONALIZED POLYELECTROLYTES - 2 - ACENTRIC SELF-ASSEMBLY THROUGH A LAYER-BY-LAYER DEPOSITION PROCESS

We have developed epoxy-based, water-soluble azo polymers containing i onizable groups in the azobenzene functionality. We describe a novel a pproach of the noncentrosymmetric self-assembly of azobenzene chromoph ores in these polymers through a layer-by-layer deposition technique. The polymers in solution function as polyelectrolytes and were assembl ed into multilayers by alternately depositing the ionic azobenzene pol ymers and commercially available polyelectrolytes of the opposite char ge on glass substrates. The chromophores in the multilayer film self-a ssemble into a noncentrosymmetric order requisite for exhibiting secon d-order NLO property. NLO coefficients are comparable to the poled, sp in-coated films of the same polymer. The self-organization of the chro mophores was further verified using transmission electron microscopic (TEM) and electroabsorption spectroscopic studies.