A random copolymer poly(4-vinylpyridine-co-acrylonitrle) (designated as P4VP-r-AN) was synthesized by solution polymerization, and characterized by the average viscosity molecular weight measurement, along with ¹H NMR, ¹³C NMR, DSC, and FTIR spectroscopy. The viscosity-average molecular weight of the P4VP-r-AN is 1.06×10⁴ g/mol, and the mass content of P4VP is about 87.1%. A new method based on ionic self-assembly technology was provided for design of side chain azocomplex (P4VP-r-AN/MY) from the protonated P4VP-r-AN (P4VP^＋-r-AN) and azobenzene dye metanil yellow (MY) in aqueous solution. The self-assembly behaviors and morphologies of P4VP-r-AN/MY were investigated by means of ¹H NMR, FTIR, DSC, UV-vis, SEM, TEM and High-resolution transmission electron microscopes and X-ray energy dispersion spectrometer (HRTEM&EDS). It was found that azobenzene complex P4VP-r-AN/MY could be self-assembled and aggregated in aqueous solution, and the aggregations shown to be solid polymeric nanospheres on the sizes of 10～200 nm in diameters. The molar ratio of MY and P4VP-r-AN in P4VP-r-AN/MY was measured at about 0.575. HRTEM&EDS were used to study the morphology and composition of the organic nanospheres. The EDS elemental analysis indicated that the spherical organic nanoparticles are indeed composed of MY dye molecules.

Key words: ionic self-assembly, polyelectrolyte, metanil yellow, azocomplex, spherical nano-aggregation