Adjustable Fluorescent Material of Terbium Hybrid in Poly (Methyl Methacrylate)—SiO₂ Copolymer Host

Abstract

In this work, the ternary copolymer of methyl methacrylate (MMA) and quadruple copolymer of MST-PEG (MSTE) were synthesized by sol-gel method. And their trivalent terbium complexes were prepared through hybrid strategy. FT-IR data confirmed that the cross-linked network of either ternary copolymer MST or quadruple copolymer of MSTE was formed by Si‒O‒Si, Si‒O‒C and Si-C bonding with molecular framework of poly (MMA-MSPMA). Trivalent terbium cooperates with ether characteristic groups of Si‒O‒Si, Si‒O‒C and C‒O‒C. The thermal behavior study of these samples by DSC indicated that MST, MST-Tb³⁺ and MSTE-Tb³⁺ behave a critical transition temperature (T_Tr) to accelerate the rate of sol-gel reactions while the PEG in MSTE- Tb³⁺ mitigates acceleration. The terbium-containing samples with or without PEG can emit sharp fluorescence at 548 nm and the fluorescent strength increases with the content of PEG. However, the emitting peak at 417 nm shows a maximum value at critical concentration of PEG. Based on the observations of microscopy and thermal history, this strength change goes with the domain conglomeration of silica crystalline.

Keywords:

• Fluorescent
• poly (methyl methacrylate)
• silica
• hybrid
• sol–gel
• lanthanide

Acknowledgments

Authors appreciate the financial supports of (1) Natural Scientific Foundation of Shandong Province through contract# Y2008B06; (2) Program of Qingdao Science & Technology, Bureau to Tackle Key Problem in Key Technology (2009-2011); and (3) International Collaborative Program of Qingdao Science & Technology Bureau, grant# 10-1-4-97-hz; (4) Shandong Province Project: Tackle Key Problem in Key Technology, #2010GGX10327) (2011-2012).