A novel photoluminescent nanohybrid of poly(ε-caprolactone) grafted Mg/Al layered double hydroxides and Tb³⁺ ions: Synthesis and characterization

다국어 초록 (Multilingual Abstract)

This paper demonstrates a systematic study of the synthesis and characterization of the hybrid of Mg-Al layer double hydroxides (LDHs), poly(ε-caprolactone) (PCL), and terbium ions (Tb<SUP>3+</SUP>). The hybrid LDH-g-PCL-Tb<SUP>3+</SUP>-1,10-phenanthroline (Phen) was prepared by the combination of ring opening polymerization (ROP), click chemistry, and coordination chemistry. First, LDHs with a molar ratio of Mg/Al=2 were prepared by the co-precipitation method, which was subsequently functionalized with (3-chloropropyl) trimethoxysilane in order to introduce azide groups through the reaction of chlorine with sodium azide. Meanwhile, the acetylene functionalized PCL was prepared by ROP of ε-CL, followed by esterification of the hydroxyl groups using succinic anhydride. The click reaction of alkyne-PCL and N<SUB>3</SUB>-LDHs successfully afforded LDH-g-PCL, which was coordinated with Tb<SUP>3+</SUP> ions in the presence of Phen. The structure and properties of the nanohybrids were investigated by FT-IR, XPS, EDS, SEM, and TGA analyses. The data indicate the coordination of Tb<SUP>3+</SUP> ions with LDH-g-PCL nanohybrids. The content of Tb<SUP>3+</SUP> ions in the LDH-g-PCL-Tb<SUP>3+</SUP>-Phen complex was calculated to be 8.7% (w/w). The LDH-g-PCL-Tb<SUP>3+</SUP>-Phen complexes showed four emission bands with high fluorescence intensity centered at 489nm (<SUP>5</SUP>D<SUB>4</SUB>→<SUP>7</SUP>F<SUB>6</SUB>), 546nm (<SUP>5</SUP>D<SUB>4</SUB>→<SUP>7</SUP>F<SUB>5</SUB>), 586nm (<SUP>5</SUP>D<SUB>4</SUB>→<SUP>7</SUP>F<SUB>4</SUB>) and 623nm (<SUP>5</SUP>D<SUB>4</SUB>→<SUP>7</SUP>F<SUB>3</SUB>) with excitation at 328nm (<SUP>3</SUP>F<SUB>6</SUB>→<SUP>5</SUP>G<SUB>6</SUB>). The stability of LDH-g-PCL-Tb<SUP>3+</SUP>-Phen complexes under UV irradiation was high, and no leaching effect was observed.