(439g) Effect of pH On the Luminescence Properties of CMC/Tb Nanocomposites

the carboxymethyl cellulose (CMC) and rare earth metal Tb( III)   Nanocomposites (CMC/Tb) were successfully synthesized over a pH range of 7-12 under water bath. The structure,surface topography and luminance were characterized by FT-IR,SEM and fluorescence spectrum. Emission and excitation spectra were obtained for the CMC/Tb Nanocomposites. And the fluorescence intensities at 544 nm of these Nanocomposites were measured under an excitation wavelength of 285 nm. It was learned that the sizes of CMC/Tb nanocomposites were from 100 to 500nm and the fluorescence intensities of Tb( III) ⁵D₄→⁷F₅ at 544 nm selective emission spectra showed that the fluorescence intensities were much stronger at pH7 and pH9 but weaker at pH10. Therefore, the pH had a great effect on the luminescence properties of CMC/Tb Nanocomposites and the results indicated that Tb( III) forming complexes with carboxymethyl cellulose were also influenced by pH.

Acknowledgments: We gratefully acknowledge the financial support provided by the National 973 project (2010CB732201), the National Natural Foundation of China (project 31270617) and the Opening Project of State Key Laboratory of Polymer Materials Engineering (Sichuan University, KF201301).