两种侧链偶氮聚电解质自组装膜中生色团取向研究

用偏振紫外光谱研究了两种侧链偶氮聚电解质静电逐层自组装膜中偶氮生色团的初始取向 .讨论了不同的组装条件对自组装膜中偶氮生色团取向的影响 .进一步探讨了偶氮聚电解质自组装膜的结构特点 .研究表明 ,侧链偶氮聚电解质自组装膜中的偶氮生色团存在一定程度的面内取向 ,自组装的各种影响条件和聚合物结构等 (pH值、侧链柔性间隔基团长度、以及偶氮生色团官能度等 )与自组装膜中偶氮生色团的面内取向程度存在一定的相关性 .通过研究偶氮生色团的取向和影响因素 ,可以深入认识侧链偶氮聚电解质的自组装行为     

Cu2+/TiO2对甲基橙的光催化降解机理

以自制的掺铜离子的混晶型二氧化钛为光催化剂,考察了甲基橙光催化降解过程中pH值和光源的影响,提出了两种不同的光催化降解机理:在高压汞灯照射下,TiO2的价带电子被激发到导带,光生电子和空穴主要通过Cu2+ 的短路循环而复合,光催化剂的活性降低;在太阳光照射下,甲基橙发生自身光敏化氧化反应,受激电子从单线态或三线态的甲基橙分子跃迁到TiO2的导带,Cu2+起到电荷传递中继站的作用,加速了注入电子向H2O2的转移,从而促进了甲基橙的光催化降解。     

偶氮连苯三酚试剂的合成及其光谱特性

合成了 2 -羧基苯胺重氮盐和 2 -羟基苯胺重氮盐 ,它们与连苯三酚偶联 ,得到新的偶氮试剂 4 - (2 -羧基苯偶氮 ) -连苯三酚和 4 - (2 -羟基苯偶氮 ) -连苯三酚。研究了偶氮试剂的红外光谱、紫外光谱和荧光光谱特性。     

在N,N-二甲基甲酰胺/水混合溶剂中制备偶氮聚电解质自组装膜

利用静电吸附逐层自组装方法在有机溶剂N,N二甲基甲酰胺(DMF)和H2O的混合介质中制备非水溶性偶氮聚电解质自组装多层膜.研究了DMF和H2O的配比对自组装膜生长、结构与表面形态的影响.结果表明,DMFH2O的混合溶剂是非水溶性偶氮聚电解质自组装的理想介质,二者之间的配比对自组装膜的生长速度,膜的结构以及表面形态均有显著影响.随着混合溶液中DMF含量的升高,自组装膜的生长速度逐渐下降但线形生长关系越来越好,所得自组装膜中偶氮生色团的H聚集程度逐渐下降,而且自组装膜的表面越来越平整.     

Photoactive Poly(aryl ether)s Containing Azobenzene Moieties on Pendants for Fabrication of Thermal Stable Surface Relief Gratings

A series of azobenzene functionalized poly(aryl ether) copolymers(azo-PAEs) containing azo moieties on pendants was prepared by direct copolymerization. The amount of azobenzene chromophores could be controlled by the feed ratio of azo-monomer. Their chemical structures and properties were characterized by means of infrared(IR) spectrometry, UV-Vis, hydrogen nuclear magnetic resonance(¹H NMR), difference scanning calorimetry(DSC), and thermogravimetric analysis(TGA). The results suggest that azo-PAEs had high glass transition temperatures(T_gs) and good thermal stability. By exposing their spin-coated films to an interference pattern laser beam, azo-PAEs could be used for the fabrication of thermal stable surface relief gratings(SRGs).     

Z-scan determination of the third-order optical nonlinearities of an azo dye using diode-pumped Nd:Yag laser

Optical nonlinearity of dye solutions are studied with considerable interest for their wide spread applications ranging from gain media in lasers to all-optical processing signal devices. The third-order nonlinear optical properties of Brilliant Crocein dye was measured by the Z-scan technique and measurements were carried out for different concentrations. The negative sign of the nonlinear refractive index n₂ indicates that this material exhibits self-defocusing optical nonlinearity and purely saturation absorption at the wavelength 532 nm of the diode-pumped Nd:YAG. These results show that Brilliant Crocein has potential applications in nonlinear optics.     

Synthesis,characterization and antibacterial studies of some new tellurated azo compounds

A series of tellurated azo compounds [i.e. (4-HOC₆H₄N=N-Ar)TeBr₃ and (4-HOC₆H₄N=N-Ar)₂TeBr₂, where Ar=5-BrC₆H₃, 5-CH₃C₆H₃ and 5-NO₂C₆H₃] were prepared by the reaction of the corresponding 2-(4-hydroxyphenylazo)aryl mercury chloride with tellurium tetrabromide in 1:1 and 2:1?mole ratio, respectively in dry dioxane as a solvent. The reduction of (4-HOC₆H₄N=N-Ar)TeBr₃ by hydrazine hydrate gave the corresponding ditelluride (i.e., (4-HOC₆H₄N=N-Ar)₂Te₂). Treatment of (4-HOC₆H₄N=N-Ar)₂TeBr₂ with hydrazine hydrate afforded the corresponding tellurides, (4-HOC₆H₄N=N-Ar)₂Te), in good yields. The structures of all newly synthesized compounds were assigned on the basis of their elemental and spectroscopic data. The antibacterial activity of tellurated azo compounds along with mercurated azo compounds was tested with agar diffusion method against the bacteria strains Staphylococcus aureus and Escherichia coli. The antibacterial activities of tellurated azo compounds were in some cases equal or better than those of the reference drug. The mercurated azo compounds were found to be the more antibacterial activity of than those of tellurated azo compounds.     

Photo-induced Alignment Behavior of Azobenzene-containing Polymer Films with Different Cross-linking Degree

Three series of amorphous copolymers containing azobenzene groups with various substituents and certain amounts of crosslinkable acrylic groups were prepared. The cross-linked polymer films were obtained by thermal polymerization of the acrylic groups in the copolymers, during which, by controlling the time of cross-linking reaction, the films can be made with different cross-linking degree (from 0 to 32%, which was monitored by FT-IR spectra measurement). Photo-induced alignment process of the films was performed under irradiation with linearly polarized light at 442 nm, and the effect of cross-linking degree on the photo-induced alignment rate was investigated. The dynamics of the photo-induced alignment was analyzed with biexponential curve fitting. The photo-induced alignment rate and the maximum transmittance of the films decreased because of the cross-linking. Furthermore, for the cross-linked samples, it was found that their saturated value of transmittances keep constant after repeated "writing" and "erasing" cycles. The findings reveal that the cross-linking of the film can effectively restrain the phototactic mass transport of azopolymer during irradiation by polarized light. The relationship between the cross-linking degree and the photo-induced alignment behavior of azopolymer is discussed in detail.     

Solvatochromism, hyperpolarizability, molecular and crystal structure of betaine dye 4-(2,4,6-triphenylpyridinium-1-yl)-phenolate

Solvatochromic effect of 4-(2,4,6-triphenylpyridinium-1-yl)-phenolate hydrate, 1, was determined. CT absorption band, which gave the shift from 23,880 (in water solution) to 14,440 cm⁻¹ (in anisole solution) allowed the molecular second order polarizability β_CT to be estimated as 59.5×10⁻³⁰ cm⁵ esu⁻¹. The crystal structure of 1 was determined: C₂₉H₂₁NO·5.78H₂O; orthorhombic, C222₁, a=15.005(9), b=24.356(4), c=7.5097(9) Å; V=2744.5(17) Å³, Z=4, D_X=1.224 g cm⁻¹; λ=0.71073 Å (Mo Kα); μ=0.087 mm⁻¹; final R₁=0.0551 for 2882 reflections [I>2σ(I)]. The molecules of 1, in an anti-parallel arrangement, form columns along the c-axis through stacking between the pyridinium ring and a phenyl ring in para position of the neighbouring molecule. Water molecules filling channels between the columns are disordered. Two of water molecules are connected by hydrogen bonds with negatively charged oxygen atom of 1. Powdered samples of 1 revealed only weak SHG response as measured using HRS method in relation to urea standard.     

Industrial Application of the Semiconductor Properties of Dyes

Effects of industrial interest have been detected in investigations on the dark conductivity and photoconductivity of dyes. For example, it was found that organic dyes can be used in the same way as inorganic photoconductors in vidicon television pickup tubes for the reproduction of images. Among other things, pointers were obtained to the formation of rectifying and photoelectrically sensitive pn junctions, to relatively high thermoelectromotive forces of doped and polymeric dyes, to the possibility of use in reprography, and to a high catalytic activity connected with the conductivity, which is already being utilized in fuel cells.