Preparation of luminescent polystyrene microspheres via surface-modified route with rare earth (Eu³⁺ and Tb³⁺) complexes linked to 2,2′-bipyridine

Luminescent polystyrene microspheres were easily fabricated from poly (styrene-co-methacrylic acid) and aqueous RE(III) chloride solution (RE=Eu, Tb) in the presence of 2,2′-bipyridine as second ligand. The negative charges of carboxyl groups on the surface of microspheres coordinated with rare earth ions at first, such as complexes covalently linked to 2,2′-bipyridine, resulting in strong photoluminescence. Various methods, including transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and fluorescence spectrophotometer, were used to characterize the resultant polystyrene composite microspheres. This work highlights the idea that it is facile to synthesis luminescent microspheres by surface-modified method directly.