Fabrication of size controllable polymeric hollow nanospheres containing azo functional groups via ionic self-assembly

Abstract

Fabrication of size controllable polymeric hollow nanospheres with azo functional groups is of great interest for applications in biomedical engineering, electronics, optics, and diagnostics. We report here a facile and economic way of fabricating polymeric hollow nanospheres with azo functional groups using ionic self-assembly of random copolymers poly(acrylonitrile)-stat-poly(4-vinyl-pyridine) and azobenzene dye metanil yellow (MY). The size of the hollow nanospheres is homogeneous and can be conveniently controlled by varying molar ratios of the copolymers to MY and molar ratios of monomers of the copolymers. The composition of the polymeric nanospheres and the self-assembly behaviors were characterized by 1H-NMR, FTIR, UV-Vis spectrophotometry, TEM, dynamic light scattering and elemental analysis. The formation process of hollow nanospheres was considered based on the results from UV-Vis spectrophotometry and TEM. Finally, the effects of azo complex composition on the morphology of the nanospheres were discussed, and the formation mechanism of polymeric hollow nanospheres was proposed.