Binary and ternary terbium complexes were synthesized: Tb(N PA) 3·4H 2O and Tb(N PA) 3(phen·2H 2O (N HPA = N phenyl 2 aminobenzoic acid and phen = 1,10 phenanthroline). These complexes were introd...Binary and ternary terbium complexes were synthesized: Tb(N PA) 3·4H 2O and Tb(N PA) 3(phen·2H 2O (N HPA = N phenyl 2 aminobenzoic acid and phen = 1,10 phenanthroline). These complexes were introduced into inorganic polymeric porous silica matrix by the sol gel method. The luminescence behavior of the complexes in silica gels was compared with the corresponding solid state complexes by means of emission, excitation spectra and luminescence lifetimes. The result indicates that the terbium ions show fewer emission lines and lower emission intensities in the silica gel than those in pure terbium complexes. The lifetimes of terbium ions in silica gel doped with terbium complexes become longer than those of terbium complexes.展开更多
For the polycondensation reaction of A_a<B_b(C_c) type, the sol fraction for post-gel is investigated from probability consideration to approach gelation condition as a limitation. Furthermore, by means of a direct...For the polycondensation reaction of A_a<B_b(C_c) type, the sol fraction for post-gel is investigated from probability consideration to approach gelation condition as a limitation. Furthermore, by means of a direct differentiation technique, a recursion formula is proposed for the evaluation of polymer moments in explicit forms for both pre-gel and post-gel.展开更多
A molecularly imprinted polymer (MIP) was formed using an inorganic polymer by a sol-gel process. The monomers which were used to synthesize the inorganic polymer were tetraethoxysilane (TEOS), triethoxymethylsilane (...A molecularly imprinted polymer (MIP) was formed using an inorganic polymer by a sol-gel process. The monomers which were used to synthesize the inorganic polymer were tetraethoxysilane (TEOS), triethoxymethylsilane (MTES), and triethoxyphenylsilane (PTES). Caffeine was chosen as a template for the molecular imprinting, and theophylline was chosen as the analogous counterpart compound. The discriminating ability of the synthesized MIP to these two-compounds was estimated in this study. The MIP showed the highest discriminating ability when the ratio of TEOS:MTES: PTES in the synthesis of the inorganic polymer was 1:1:3, the reaction temperature was 50?C, and the pH of the reaction system was ~6.5.展开更多
Sol-gel is a promising technique for the synthesis of organic-inorganic hybrid materials of class II. One of the most interesting applications for these hybrid materials is as solid polymer electrolytes (SPEs). In par...Sol-gel is a promising technique for the synthesis of organic-inorganic hybrid materials of class II. One of the most interesting applications for these hybrid materials is as solid polymer electrolytes (SPEs). In particular, when doped with proton species they have potential applications in fuel cells. In this paper SiO2–PEG1500 hybrids of class II were prepared with different contents of SiO2 and phosphotungstic acid. The influence of the SiO2 content in the matrix has been studied. The samples were investigated by thermal analysis (TGA and DSC), X-ray diffraction, infrared spectros-copy (IR), scanning electron microscopy (SEM) and Impedance Spectroscopy.展开更多
Superoleophobic nanocomposite coatings with improved hydrophobic properties were obtained by incorporation of a perfluoroalkyl polymer in hybrid sol-gel matrix containing silica and titania nanoparticles. SiO2 and TiO...Superoleophobic nanocomposite coatings with improved hydrophobic properties were obtained by incorporation of a perfluoroalkyl polymer in hybrid sol-gel matrix containing silica and titania nanoparticles. SiO2 and TiO2 nanoparticles were synthesized based on sol-gel precursors utilizing tetraethyl orthosilicate, 3-glycidoxypropyl trimethoxysilane, and tetra (n-butyl orthotitanate). SEM and EDX images of the coating demonstrated that a Silica nanosphere had been aggregated in superporous structure. The analysis results show that nano-sized inorganic particles (10 - 20 nm) have a uniform distribution and dispersion. By increasing the PFOTES, the oleophobicity of coatings increased due to lowering of surface energy in the presence of fluoropolymer. Results of EIS measurement show that PFOTES and TiO2 nanoparticles increased anti-corrosion property of hybrid coatings. This method introduces a simple way to produce water- and oil-repellent self-cleaning coatings on large areas of different substrates like glass, ceramic, metal and composites.展开更多
A tricyanofuran （TCF） acceptor-based nonlinear optical （NLO） chromophore （2-（3-cyano-4-（4-（（2- hydroxyethyl）（methyl）amino）styryl）-5,5-dimethylfuran-2（5H）-ylidene）malononitrile abbr. FS） was synthesiz...A tricyanofuran （TCF） acceptor-based nonlinear optical （NLO） chromophore （2-（3-cyano-4-（4-（（2- hydroxyethyl）（methyl）amino）styryl）-5,5-dimethylfuran-2（5H）-ylidene）malononitrile abbr. FS） was synthesized and then reacted with 3-isocyannatopropyl triethoxysilane （ICTES） to form a functionalized silicon alkoxide precursor （named ICTES-FS）. Sol solutions were obtained after co-hydrolysis/condensation of ICTES-FS, tetraethoxysilane （TEOS） and 3-（Trimethoxysilyl）propyl methacrylate （TSPM）. Transparent films were only fabricated with the sol containing high concentration of TSPM. Higher concentration of TSPM was found useful to abate dipolar chromophore interactions and consequent aggregation problems. Second- order NLO properties and temporal stability of sol-gel films were also investigated by virtue of in situ second harmonic generation （SHG）.展开更多
Nano-TiO2 particles with a range of crystallite sizes were synthesized by a conventional sol-gel method,and then used as nanoparticle substrates in the synthesis of LLDPE/TiO2 nanocomposites via in situ polymerization...Nano-TiO2 particles with a range of crystallite sizes were synthesized by a conventional sol-gel method,and then used as nanoparticle substrates in the synthesis of LLDPE/TiO2 nanocomposites via in situ polymerization of ethylene/1-hexene with zirconocene/MMAO catalyst.It was found that the size of the nano-TiO2 crystallite nanoparticles can influence the catalytic activity in the polymerization system.The larger nano-TiO2 crystallites provided better catalytic activity in the polymerization system due to more space for monomer attack.In addition,by thermo-gravimetric analysis,it can be seen that the larger nano-TiO2 crystallites also exhibited lower interaction with available MMAO.Consequently,the MMAO reacted more efficiently with the zirconocene catalyst during the activation process,and enhanced polymerization catalysis.All the polymer nanocomposites products did not have well defined melting temperature indicating non-crystalline polymers.This is due to the high amount of hexene incorporation(based on 13C NMR).The difference in crystallite sizes of the nano-TiO2 also affected how 1-hexene became incorporated into the polymer nanocomposites.The smaller crystallite size of nano-TiO2 allowed greater 1-hexene incorporation due to depression of the reactivity of the ethylene.The contribution of this work helps develop a better understanding of the role of nano-TiO2 in the catalytic activity of the polymerization system and in the microstructure of the polymer composite product.However,this study only considers work on the laboratory scale,so for commercial application of these results,it is necessary to scale up the polymerization process.It is only at this stage,that other physical properties,such as the mechanical properties of these materials can be sensibly determined.展开更多
文摘Binary and ternary terbium complexes were synthesized: Tb(N PA) 3·4H 2O and Tb(N PA) 3(phen·2H 2O (N HPA = N phenyl 2 aminobenzoic acid and phen = 1,10 phenanthroline). These complexes were introduced into inorganic polymeric porous silica matrix by the sol gel method. The luminescence behavior of the complexes in silica gels was compared with the corresponding solid state complexes by means of emission, excitation spectra and luminescence lifetimes. The result indicates that the terbium ions show fewer emission lines and lower emission intensities in the silica gel than those in pure terbium complexes. The lifetimes of terbium ions in silica gel doped with terbium complexes become longer than those of terbium complexes.
文摘For the polycondensation reaction of A_a<B_b(C_c) type, the sol fraction for post-gel is investigated from probability consideration to approach gelation condition as a limitation. Furthermore, by means of a direct differentiation technique, a recursion formula is proposed for the evaluation of polymer moments in explicit forms for both pre-gel and post-gel.
文摘A molecularly imprinted polymer (MIP) was formed using an inorganic polymer by a sol-gel process. The monomers which were used to synthesize the inorganic polymer were tetraethoxysilane (TEOS), triethoxymethylsilane (MTES), and triethoxyphenylsilane (PTES). Caffeine was chosen as a template for the molecular imprinting, and theophylline was chosen as the analogous counterpart compound. The discriminating ability of the synthesized MIP to these two-compounds was estimated in this study. The MIP showed the highest discriminating ability when the ratio of TEOS:MTES: PTES in the synthesis of the inorganic polymer was 1:1:3, the reaction temperature was 50?C, and the pH of the reaction system was ~6.5.
文摘Sol-gel is a promising technique for the synthesis of organic-inorganic hybrid materials of class II. One of the most interesting applications for these hybrid materials is as solid polymer electrolytes (SPEs). In particular, when doped with proton species they have potential applications in fuel cells. In this paper SiO2–PEG1500 hybrids of class II were prepared with different contents of SiO2 and phosphotungstic acid. The influence of the SiO2 content in the matrix has been studied. The samples were investigated by thermal analysis (TGA and DSC), X-ray diffraction, infrared spectros-copy (IR), scanning electron microscopy (SEM) and Impedance Spectroscopy.
文摘Superoleophobic nanocomposite coatings with improved hydrophobic properties were obtained by incorporation of a perfluoroalkyl polymer in hybrid sol-gel matrix containing silica and titania nanoparticles. SiO2 and TiO2 nanoparticles were synthesized based on sol-gel precursors utilizing tetraethyl orthosilicate, 3-glycidoxypropyl trimethoxysilane, and tetra (n-butyl orthotitanate). SEM and EDX images of the coating demonstrated that a Silica nanosphere had been aggregated in superporous structure. The analysis results show that nano-sized inorganic particles (10 - 20 nm) have a uniform distribution and dispersion. By increasing the PFOTES, the oleophobicity of coatings increased due to lowering of surface energy in the presence of fluoropolymer. Results of EIS measurement show that PFOTES and TiO2 nanoparticles increased anti-corrosion property of hybrid coatings. This method introduces a simple way to produce water- and oil-repellent self-cleaning coatings on large areas of different substrates like glass, ceramic, metal and composites.
基金Funded by the National Natural Science Foundation of China (Nos.50532030 and 50625206) and PCSIRT
文摘A tricyanofuran （TCF） acceptor-based nonlinear optical （NLO） chromophore （2-（3-cyano-4-（4-（（2- hydroxyethyl）（methyl）amino）styryl）-5,5-dimethylfuran-2（5H）-ylidene）malononitrile abbr. FS） was synthesized and then reacted with 3-isocyannatopropyl triethoxysilane （ICTES） to form a functionalized silicon alkoxide precursor （named ICTES-FS）. Sol solutions were obtained after co-hydrolysis/condensation of ICTES-FS, tetraethoxysilane （TEOS） and 3-（Trimethoxysilyl）propyl methacrylate （TSPM）. Transparent films were only fabricated with the sol containing high concentration of TSPM. Higher concentration of TSPM was found useful to abate dipolar chromophore interactions and consequent aggregation problems. Second- order NLO properties and temporal stability of sol-gel films were also investigated by virtue of in situ second harmonic generation （SHG）.
基金the Thailand Research Fund (TRF) for its support of the DBG52-B Jongsomjit Project
文摘Nano-TiO2 particles with a range of crystallite sizes were synthesized by a conventional sol-gel method,and then used as nanoparticle substrates in the synthesis of LLDPE/TiO2 nanocomposites via in situ polymerization of ethylene/1-hexene with zirconocene/MMAO catalyst.It was found that the size of the nano-TiO2 crystallite nanoparticles can influence the catalytic activity in the polymerization system.The larger nano-TiO2 crystallites provided better catalytic activity in the polymerization system due to more space for monomer attack.In addition,by thermo-gravimetric analysis,it can be seen that the larger nano-TiO2 crystallites also exhibited lower interaction with available MMAO.Consequently,the MMAO reacted more efficiently with the zirconocene catalyst during the activation process,and enhanced polymerization catalysis.All the polymer nanocomposites products did not have well defined melting temperature indicating non-crystalline polymers.This is due to the high amount of hexene incorporation(based on 13C NMR).The difference in crystallite sizes of the nano-TiO2 also affected how 1-hexene became incorporated into the polymer nanocomposites.The smaller crystallite size of nano-TiO2 allowed greater 1-hexene incorporation due to depression of the reactivity of the ethylene.The contribution of this work helps develop a better understanding of the role of nano-TiO2 in the catalytic activity of the polymerization system and in the microstructure of the polymer composite product.However,this study only considers work on the laboratory scale,so for commercial application of these results,it is necessary to scale up the polymerization process.It is only at this stage,that other physical properties,such as the mechanical properties of these materials can be sensibly determined.
