Synthesis and spectroscopic characterization of Eu3+-doped poly(acrylic acid)

Eu3+-doped poly(acrylic acid) was synthesized by polymerization in aqueous solution of the monomer partially neutralized with different amounts of Eu2O3 (0.5-5.0 mol% of Eu3+) using potassium persulfate as initiator. The C-13-NMR, Fourier transform infrared (FT-IR) and luminescent Eu3+-doped polymer was characterized by H-1- and spectroscopy. The NMR and FT-IR results show clear evidence of the coordination between Eu3+ cations and the carboxylate anions which result of the partial neutralization of the monomer prior to polymerization. On the other hand, the polymer phosphorescence intensity was observed to decrease with the increasing of the Eu3+ concentration due to the complex formation. Additionally, the homogeneous broadening and the relative intensity of the D-5(0) --> F-7(1,2) transitions indicate that the dopant ions are uniformly distributed in low symmetry coordination sites. (C) 1999 Elsevier Science B.V. All rights reserved.