Enhanced fluorescence and structural characteristics of carboxymethyl cellulose/Eu(III) nano-complex: Influence of reaction time

CMC/Eu(III) nano-complexes were synthesized by reacting Eu3+ with carboxymethyl cellulose (CMC). The SEM and EDS showed that particle size was less than 100 nm and evenly distributed. FTIR and XPS indicated that the oxygen atoms in -COO-, -OH, and -C-O-C were involved in the complexation with Eu3+, yet, the 0 atoms were involved in different positions on anhydroglucose rings depending on reaction time. It was found that there were good energy matches between energy levels on ground state of CMC and D-5(0) Eu(III). Moreover, the intensities of D-5(0) -> F-7(2) of the nano-complexes were stronger than that of D-5(0) -> F-7(1), which indicated that the Eu(III) was not in the center of symmetry. The optimized reaction time was 35 min, at this reaction time the smallest particle size and uniform distribution was obtained, the coordination structure was advantageous for the energy absorption transfer and emission. (C) 2015 Elsevier Ltd. All rights reserved.