Fluorescent Copolymers of N-Vinylcarb-Azole and Eu-Complexed Acrylic Acid as Anti-Falsification Packaging MaterialsReport as inadecuate




Fluorescent Copolymers of N-Vinylcarb-Azole and Eu-Complexed Acrylic Acid as Anti-Falsification Packaging Materials - Download this document for free, or read online. Document in PDF available to download.

Europium complexes were excellent chromophores that exhibited intense fluorescence with a narrow spectral bandwidth 5-10 nm. But non-uniform blending or dispersion of complex resulted in phase separation, decomposition and inefficient energy transfer to reduce emission efficiency. The complexes were covalently attached to the main chain of polymers, which improved film quality, thermal stability and solubility. EuTTA2AAphen as europium complex monomer ECM was prepared by Eu3+ coordinating with 1,10-phenanthroline phen, acrylic acid AA and 2-thenoyltrifluoroacetone TTA. Fluorescent Polymer 1 P1, molar ratio for ECM-N-vinylcarbazole, NVK, 1-60 and Polymer 2 P2, 1-30 were synthesized. The emission wavelength of ECM in tetrahydrofuran THF was at 614nm. With the increasing of molar ratio of Eu in polymers, the emission peak of P2 in the 350-500 nm region in either film or THF was lower and one of P2 at about 614 nm was higher compared to P1. Collective states of polymers in both film and THF had less effect on emission wavelength at 614 nm. Glass transition temperatures and thermal decomposition temperatures of ECM, P2 and P1 were observed at 118, 174, 178 ?C and 269, 250, 227?C, respectively, which showed that they were high thermal stabilities. From the differential scanning calorimetry DSC curves of P2 and P1, no noticeable crystallization took place. The atomic force microscope AFM images of copolymers film revealed good film quality to avoid phase separation. The big overlap between emission spectra of carbazole and absorption spectra of Eu complex moieties raised effectively intramolecular energy transfer from carbazole unit to europium ions and improved emission efficiency. It was desirable to prepare fluorescent inks containing P1 and P2 for anti-falsification packaging.

KEYWORDS

Europium complex; Acrylic acid; N-vinylcarbozole; Energy transfer; Fluorescent copolymer.

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Author: Wenguan Zhang, Lian Qin, Shengmin Zhao

Source: http://www.scirp.org/



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