Lanthanide complex/polymer composite optical resin with intense narrow band emission, high transparency and good mechanical performance

Novel composite resins possessing good luminescent properties have been synthesized through a free radical copolymerization of styrene, alpha-methylacrylic acid and the binary or ternary complexes of lanthanide ions (Eu3+ and Tb3+). These polymer-based composite resins not only possess good transparency and mechanical performance but also exhibit an intense narrow band emission of lanthanide complexes under UV excitation. We characterized the molecular structure, physical and mechanical performance, and luminescent properties of the composite resins. Spectra investigations indicate that alpha-methyl-acrylic acid act as both solubilizer and ligand. Photoluminescence measurements indicate that the lanthanide complexes show superior emission lines and higher intensities in the resin matrix than in the corresponding pure complex powders, which can be attributed to the restriction of molecular motion of complexes by the polymer chain networks and the exclusion of water molecules from the complex. We also found that the luminescence intensity decreased with increasing content of alpha-methylacrylic acid in the copolymer system. The lifetime of the lanthanide complexes also lengthened when they were incorporated in the polymer matrix. In addition, we found that the relationships between emission intensity and Tb (Eu) content exhibit some extent of concentration quenching.

Multi-color long-lasting phosphorescence of rare earth ions in CdSiO3 matrix

A series of rare earth ions doped CdSiO3:RE3+(RE=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) multi-color long-lasting phosphorescence phosphors are prepared by the conventional high-temperature solid-state method. The results of XRD measurement indicate that the products fired under 1050degreesC for 3 h have a good crystallization without any detectable amount of impurity phase. Rare earth ions doped CdSiO3 phosphors possess excellent luminescence properties. When rare earth ions such as Y3+, La3+, Gd3+, Lu3+, Ce3+, Nd3+, Ho3+, Er3+, Tm3+ and Yb3+ are introduced into the CdSiO3 host, one broadband centered at about 420 nm resulting from traps can be observed. In the case of other earth ions such as Pr3+, Sm3+, Eu3+, Tb3+ and Dy3+, their characteristic line emitting as well as the similar to420 nm broadband luminescence can be obtained. The mixture of their characteristic line emitting with the similar to420 nm broadband luminescence results in various afterglow color.

Rheology and morphology of reactively compatibilized PP/PA6 blends

This work aims to use the Palierne emulsion type model to describe the relationship between the rheological response to small amplitude oscillatory deformation and morphology of polypropylene/polyamide 6 (PP/PA6) blends compatibilized with maleic anhydride grafted polypropylene (PP-g-MAH). It was found that the Palierne emulsion type model could describe very well the linear viscoelastic responses of binary uncompatibilized PP/PA6 blends and failed to describe the ternary compatibilized PP/PP-g-MAH/PA6 blends. These features could be attributed to the fact that the morphology of the ternary blends was not of the emulsion type with the PA6 particles dispersed in the PP matrix but of an emulsion-in-emulsion type, i.e., PA6 particles dispersed in the PP matrix themselves contained PP or PP-g-MAH inclusions. By consideration of PP-in-PA6 particles as pure PA6 particles, where the volume fraction of the PA6 phase was increased accordingly, the Palierne emulsion type model could work very well for a ternary blending system. Preshear at low frequencies modified the morphology of both binary and ternary blends. The particles of the dispersed phase (PA6) became more uniform. These results suggested that the Palierne emulsion type model could be used to extract information on rheological properties and interfacial tension of polymer blends from known morphology and vice versa.

Preparation and luminescence properties of hybrid materials containing europium(III) complexes covalently bonded to a silica matrix

A new kind of luminescent organic-inorganic hybrid material (denoted Hybrid I) consisting of europium 1,10-phenanthroline complexes covalently attached to a silica-based network was prepared by a sol-gel process. 1,10-Phenanthroline grafted to 3-(triethoxysilyl)propyl isocyanate was used as one of the precursors for the preparation of an organic-inorganic hybrid materials. For comparison purposes, the hybrid material (denoted Hybrid II) in which phenanthroline was not grafted onto the silica backbone of the frameworks was also prepared. Elemental analysis; NMR, FT-IR, UV/vis absorption, and luminescence spectroscopies, and luminescence decay analysis were used to characterize the obtained hybrid materials. It is shown that the homogeneity of Hybrid I is superior to that of Hybrid II, and a higher concentration europium can be incorporated into Hybrid I than Hybrid II. Excitation at the ligand absorption wavelength (283 nm) resulted in the strong emission of the Eu3+ D-5(0)-F-7(J) (J = 0-4) transition lines as a result of the efficient energy transfer from the ligands to the EU3+ in Hybrid I. The number of water molecules coordinated to the europium ion was estimated, and the structure of the as-synthesized Hybrid I was predicted on the basis of the experimental results.

Rapid molecular weight determination of recombinant hirudin by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The molecular weight of recombinant hirudin ( rHV-2) was determined rapidly by matrix-assisted laser desorption/ionization time of fight mass spectrometry (MALDI-TOF-MS). The effects of the three types of matrixes were compared and discussed, alpha-cynao-4-hydroxycinnamic acid was proved to be the best matrix. It showed that MALDI-TOF-MS was superior to the traditional method of molecular weight determination of the biological macromolecules. The mass spectrum data proved that the primary structure of rHV-2 was correct and there was no amino acid deletion, mutation and modification in its expression, refolding and purification.

A novel way to enhance electroluminescence performance based on soluble binary and ternary europium 1,1,1-trifluoroacetylacetonate

Five rare earth complexes (Gd(acae)(3), Gd(TFacaC)(3), Eu(acaC)(3), Eu(TFacaC)(3) and Eu(TFacaC)(3)bipy; acac, acetylacetone; TFacac, 1,1,1-trifluoroacetylacetone; bipy, 2,2'-bipyridyl) were synthesized. By comparing the phosphorescence spectra of Gd(acac)(3) and Gd(TFacac)(3) the effect of the replacement of hydrogen by fluorine was examined. Organic light-emitting devices (OLEDs) based on the corresponding europium complexes as emissive layers were also fabricated by the spin-coating method. The triple-layer-type device with the structure glass substrate/ITO (indium-tin oxide)/PVK [poly(N-vinylcarbazole)]/(PVKEu)-Eu-.(TFacac)(3)bipy:PBD[2-(4-bibipyyl)-5-(4-t-butylbipyl-1,3,4-oxadiazole)]/PBD/Al (aluminum) exhibits a brighter red luminescence than those devices with Eu(acac)(3) and Eu(TFacac)(3) complexes as emissive centers upon applying a d.c. voltage.

Study of electron transfer across the liquid/ice-like matrix interface by scanning electrochemical microscopy

In this work, we report the findings of a study on scanning electrochemical microscopy (SECM) to investigate the interfacial electron-transfer (ET) reaction between the 7,7,8,8-tetracyanoquinodimethane radical anion (TCNQ(.-)) in 1,2-dichloroethane and ferricyanide in an ice-like matrix (a mixture of insulting ice and conductive liquid) under low temperatures. Experimental results indicate that the formed liquid/ice-like matrix interface is superficially similar in electrochemical characteristics to a liquid/liquid interface at temperatures above -20 degreesC. Furthermore, imaging data show that the surface of the ice-like matrix is microscopically flat and physically stable and can be applied as either a conductive or an insulting substrate for SECM studies. Perchlorate ion was selected as the common ion in both phases, the concentrations of which controlled the interfacial potential difference. The effect of perchlorate concentration in the DCE phase on interfacial reactions has been studied in detail. The apparent heterogeneous rate constants for TCNQ(.-) oxidation by Fe(CN)(6)(3-) in another phase under different temperatures have been calculated by a best-fit analysis, where the experimental approach curves are compared with the theoretically derived relationships. Reaction rate data obey Butler-Volmer formulation before and after the freezing point, which is similar to most other known cases of ET reactions at liquid/liquid interfaces. However, there is a sharp change observed for heterogeneous rate constants around the freezing point of the aqueous phase, which reflects the phase transition. At temperatures below -20 degreesC, surface-confined voltammograms for the reduction of ferricyanide were obtained, and the ice-like matrix became an insulating one, which indicates that the aqueous phase is really a frozen phase.

Novel trichromatic phosphor codoped with two rare earth ions in a single matrix

The luminescence properties of CaBPO5: Eu, Tb phosphor and the sensitization of Ce3+ were investigated. The CaBPO5: Eu, Tb phosphors were synthesized in the ambient air and the emission spectra of Eu3+, Tb3+ and Eu2+ were Observed in the phosphor. The result shows that there is electron transfer between conjugate rare earth ions. Sensitization of Ce3+ can improve the intensity of emission of Tb3+ and Eu2+. A novel trichromatic lamp phosphor codoped with Eu3+-Tb3+ in matrix CaBPO5 is then predicted.

Matrix effects in flow injection-inductively coupled plasma mass spectrometry

Matrix effects in now injection (FI) inductively coupled plasma mass spectrometry has been studied,and the results have been compared with those of continuous nebulization. The matrix element As and nu with higher ionization potential ( > 9eV) have enhancement effect on the analyte signal,and the heavier the analyte mass, the smaller the enhancement effects by Fl. The matrix elements Cu, In, Li, Na and Pb with lower ionization potential have suppression effect on the analyte signal. The heavier the matrix element mass, the more severe the suppression effects. The heavier the analyte mass, the smaller the suppression effects. The higher ionization potential of analyte, the more severe the suppression effects. Compared with continuous nebulization, the degree of suppression effect is smaller and the degree of the enhancement effect is larger by Fl.

Luminescence properties of Eu(phen)(2)Cl-3 doped in sol-gel-derived SiO2-PEG matrix

Rare earth complex Eu(phen)(2)Cl-3 was introduced into a SiO2-PEG-400 hybrid material by a sol-ger method. The result indicated that Poly(ethylene glycol) (PEG) could associate with Eu3+ and change the surroundings of Eu3+ in the hybrid material, greatly improving the decay time. Transparent SiO2-PEG400 hybrid doped with a very small amount of Eu(phen)(2)Cl-3 has better mechanical properties and can retain excellent luminescence properties of the rare earth complex. (C) 2000 Elsevier Science B.V. All rights reserved.

Silica sol-gel composite film as an encapsulation matrix for the construction of an amperometric tyrosinase-based biosensor

An amperometric tyrosinase enzyme electrode for the determination of phenols was developed by a simple and effective immobilization method using sol-gel techniques. A grafting copolymer was introduced into sol-gel solution and the composition of the resultant organic-inorganic composite material was optimized, the tyrosinase retained its activity in the sol-gel thin film and its response to several phenol compounds was determined at 0 mV vs. Ag/AgCl (sat. KCI). The dependences of the current response on pH, oxygen level and temperature were studied, and the stability of the biosensor was also evaluated. The sensitivity of the biosensor for catechol, phenol and p-cresol was 59.6, 23.1 and 39.4 muA/mM, respectively. The enzyme electrode maintained 73% of its original activity after intermittent use for three weeks when storing in a dry state at 4 degreesC. (C) 2000 Elsevier Science S.A. All rights reserved.

Matrix effects in inductively coupled plasma mass spectrometry by use of organic solvents

Matrix effects arising from ethanol, propanol, glycerol, acetic acid, ethylenediamine and triethanolamine in inductively coupled plasma mass spectrometry have been studied. Addition of ethanol, propanol, glycerol, acetic acid, ethylenediamine and triethanolamine into solution has an enhancement effect on the signal intensity of analyte with ionization potential between 9 and 11 eV. The ethylenediamine and triethanolamine have higher enhancement effect on the signal intensity of Hg than that of ethanol, propanol, glycerol and acetic acid. Addition of ethylenediamine and triethanolamine into solution has a suppression effect on the signal intensity of Ph and Sr. The mechanism of the enhancement or suppression was investigated. The signal enhancement of Hg in the presence of ethylenediamine and triethanolamine is not caused by improved degree of ionization of Hg and nebulization efficiency. The suppression effects of Ph and Sr in the presence of ethylenediamine and triethanolamine are due to decrease of atomization efficiency of these elements. A method for the determination of Hg in the biological standard samples Ly ICP-MS was developed.

Analysis of monodispersed polyaniline oligomers by matrix-assisted laser desorption ionization mass spectrometry

Monodispersed polyaniline oligomers was studied by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS), It is found that MALDI-TOF-MS is not only a direct, accurate and rapid tool for the analysis of monodispersed polyaniline oligomers, but also a useful technique for the design of synthetic route.

Resonant two-photon cross-section calculations for transitions to 4f5d state in Pr3+: YAG using density matrix theory

The density matrix resonant two-photon absorption (TPA) theory is applied to a rare-earth ion-doped laser crystal. TPA cross sections for transitions from the ground state to the first 4f5d state in Pr3+:YAG are calculated. The results indicate the density matrix TPA theory is attractive in studying TPA in laser crystals. (C) 2000 Elsevier Science B.V. All rights reserved.