Self-assembly of photo-responsive azo polyelectrolytes

Three azo polyelectrolytes were successfully fabricated into self-assembled multilayers through a layer-by-layer dipping technique, The surface morpho logy and its variation with the bilayer growth were investigated with atomi c force microscopy(AFM). The cis-trans isomerization of the self-assembled thin films was studied with UV-Vis spectroscopy and compared with the spin- coated films, PEAPE/PDAC and PPAPE/PDAC multilayers show significant photoc hromic effect upon UV light irradiation. In dark condition, the rates of ci s-to-trans isomerization depend on the chromophore structure. For polyelect rolytes containing the same chromophores, the azo dyes in self-assembled mu ltilayer recover much faster from cis to trans isomer than those in spin-co ated films.