Abstract: The aggregation behavior of a series of side-chain azo polyelectrolytes (PPAPE) was studied in aqueous and tetrahydrofuran(THF)/water mixed media. The aggregate process was traced with UV-Vis absorption spectroscopy. The critical aggregate concentration(CAgC) of PPAPEin aqueous solution was determined by measuring the surface tension values of the related solutions with different concentrations. The self-assembled supermolecular structures were characterized with transmission electron microscopy(TEM). The results show that the azo chromophores tethered to PPAPE H-aggregate under a suitable condition and further aggregate into nanoscale structures. Following with the aggregation process, the(max obviously blue-shifts and the photochromic effect of azo chromophores is significantly weakened. Although the pHof aqueous solutions also have a significant effect on the photochromic effect, however, these two kinds of effects have obviously different mechanisms.

Key words: Aggregation, Nanoscale structures, Hydrophobicity, Azo polyelectrolytes