Photophysical studies of polyvinylcarbazole polymer films

Polyvinylcarbazole (PVK) films have been prepared by solution method. Their absorption spectra, photoluminescence, and electroluminescence have been studied. Absorption in pure PVK is found to be high at lower wavelengths in UV region and decreases in visible range. In case of I₂ doped PVK, absorption is observed in visible region also. The photoluminescence is obtained in pure PVK when exited by violet or blue light but in case of I₂ doped PVK, similar excitation gives low intensity peaks in yellow–green region. The results indicate that I₂ levels in PVK causes absorption in 400–600 nm wavelength range and makes the deexcitation of the molecules nonradiative. Light emission by application of ac voltage from mains up to 100 V has been studied. Nonlinear increase in emission intensity has been observed with increasing voltage. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 722–726, 2007     

Studies on the TBA test for rancidity grading: II. TBA reactivity of different aldehyde classes

The TBA reactivities of several aldehydes, most of them known as ordinary products of lipid autoxidation, have been investigated systematically. Gas liquid chromatography-purified alkanals, 2-alkenals and 2,4-alkadienals were reacted with TBA in water solution. The formation of pigments with maximum absorbance at 450 and 530 nm was measured at optimum time-temperature conditions-different for readings at 450 and 530 nm- and values for absorbance per mole aldehyde were calculated. These values show that on reaction with TBA all studied aldehydes build a yellow 450 nm pigment, while only 2,4-alkadienals and, to a lesser extent, 2-alkenals produce the red 530 nm pigment. Consequently both pigments are measures of aldehydic products of lipid autoxidation: In the case of predominant unsaturated aldehyde formation, determination of the pigment with maximum absorbance at 530 nm is preferable. However, if alkanals are predominant, the determination of the yellow pigment at 450 nm is more apporpriate, as it grants higher sensitivity. The first paper in this series was published inFette, Seifen, Anstrichmittel 72:635 (1970).     

Cu and Ag Nanoparticles Films Deposited on Glass Substrate Using Cold Cathode Ion Source

Structural, electrical and optical properties of Cu and Ag nanoparticles thin films deposited on glass substrates prepared by sputtering were investigated. Cold cathode ion source used for sputtered of copper and silver targets to deposit nanoparticles thin films on glass substrate using argon gas. X-ray diffraction was used to study the structure and the grain size of thin film which reveals that average grain size is in nano region. Copper nanoparticles was in rang 14 nm and silver nanoparticles size was 20 nm in first peak using Scherrer’s method. The electrical resistivities of copper and silver thin films were also investigated. The thin film resistance Rs of Cu and Ag equals 1.33 and 6.35 Ω respectively. I-V characteristics of thin films were recorded at room temperature and are found to be linear. Optical properties of the synthesized materials are studied by UV–Vis in the wavelength range 200–800 nm. The calculated band gap for the Cu thin film on glass are estimated to be E_gCu = 2.18 eV.     

绿色和黄色银胶的光化学制备及其共振散射光谱研究

研究了不同光源、光照时间、反应物浓度等对绿色银胶形成的影响,分别制备了绿色银胶和黄色银胶、透射电镜显示,它们的平均粒径分别为100nm和40nm。绿色银胶在393.9nm和713.3nm处有两个吸收峰;黄色银胶在419.3nm处有一较宽的吸收峰,它们的最强共振散射峰位于470nm处;绿色银胶在340nm和680nm还有两个小共振峰。     

偶氮染料掺夹高分子聚合物PMMA的光信息存储性质研究

本文利用旋涂法(Spin-Coating)在单晶硅片和k9玻璃上分别制备了5-Br-PADAP,DMTAM,TADEB,DMTAA和5-Me-BTAEB五种杂环偶氮染料掺杂高分子聚和物聚甲基丙烯酸甲酯(PMMA)薄膜。测试了薄膜吸收,透过和反射光谱,通过椭圆偏振光谱计算了薄膜的光学常数。结果显示偶氮染料薄膜在450~600nm之间均有强而宽的吸收,5-Br-PADAP,DMTAM,TADEB,DMTAA参杂PMMA薄膜在514nm处具有较大的n值与较低的k值相匹配,有望作为与Ar+激光器相匹配的光盘记录介质;5-Me-BTAEB参杂PMMA薄膜在633nm处具有较大的n值与较低的k值相匹配,有望作为与He-Ne激光器相匹配的光存储记录介质材料。     

无机反射隔热颜料的制备及性能研究

采用焙烧法制备了4种无机反射隔热颜料钛铬黄、铬绿、钴蓝和铁黑,通过X射线衍射技术（XRD）、激光粒径粒度分析仪、紫外-可见-近红外分光光度计等对颜料进行了表征。最后将制得的颜料制备成涂料与普通颜料进行隔热性能对比测试。结果表明,所制颜料具有优异的太阳光反射性能,TSR值可达30％-67％;应用在涂料中可有效提高涂料自身的反射隔热性能,相对普通颜料,温度可降低6～30℃,节约能耗15％～40％。     

Ag NPs改性鱼鳞明胶-琼脂复合膜的制备及性能表征

利用鱼鳞明胶作为还原剂和稳定剂制备银纳米颗粒（silver nanoparticles, Ag NPs），研究Ag NPs添加量（0.04wt%-0.2wt%）对鱼鳞明胶-琼脂复合膜的理化性能和抗菌性能的影响。通过透射电子显微镜和X射线粉末衍射对合成的Ag NPs进行表征，结果表明制得Ag NPs为球形形貌，平均粒径为9.3 ?1.8 nm。随着Ag NPs添加量的增加，鱼鳞明胶-琼脂复合膜的色泽变黄渐深，透明度下降，对紫外和可见光的吸收增强，同时，复合膜的断裂延展性、水蒸气阻隔性能和耐水性能显著增强，而厚度和抗拉强度却无明显变化。FTIR和热重分析结果表明，Ag NPs与膜基质间存在化学相互作用，并在一定程度上改善了复合膜的热稳定性。抑菌环实验结果显示，复合膜可以在0.04wt%-0.2wt%较低的银浓度下实现良好的抗菌效果。研究结果将为鱼鳞明胶可降解抗菌包装材料的开发提供新思路。     

Transparent plasticised PVC film with ultraviolet and high-energy visible light shielding performance

In this paper, the ultraviolet (UV) absorbers and pigment yellow were added into the plasticised poly (vinyl chloride) (PVC) films for the purpose of improving the UV and high-energy visible light (HEV) shielding performance. The optical properties were investigated by a Ultraviolet-visible-near-infrared (UVPC) spectrophotometer and a transmission & haze meter. It was found that all the samples exhibited high transmittance and low haze. UV326 was more effective than UV531 as an UV absorber. Pigment yellow played a positive role in the optical properties. By a simple combination of 0.5?phr UV326 and 6?×?10^?3?phr pigment yellow, more than 80% optical transparency in the visible light range (400–800?nm) and 90% shielding efficiency of UV light (from 200 to 400?nm) were realised. Furthermore, the presence of pigment yellow in PVC matrix could effectively block HEV, and the average transmittance of HEV decreased with the increasing pigment yellow concentration.     

Superficial colouring of lead crystal glass by sol–gel coatings

Sol–gel silver containing coatings have been prepared and applied upon lead crystal glass. Both undoped and arsenic oxide-doped lead crystal glasses have been used as substrates. Arsenic oxide was introduced with different percentages as a thermoreducing agent, with the aim to favour silver ions reduction and aggregation to form nanosized colloids. Such silver colloids yielded a superficial yellow ruby colouring, due to their known surface plasmon resonance band in the visible range (∼420 nm). The influence of the experimental parameters to obtain yellow ruby colouring (percentage of arsenic oxide in the lead crystal base glass; silver content of the coatings precursor sol; coating thickness; atmosphere, temperature and time for thermal densification; etc.) were investigated. Samples were studied by transmission electron microscopy and optical spectroscopy (absorption and transmission). Colour co-ordinates, dominant wavelength and colour purity percentage were calculated from the corresponding transmission visible spectra. The role of the thermoreducing dopant (arsenic oxide) is essential for obtaining superficial yellow colouring. The higher the percentage of arsenic oxide, the higher is the intensity of the yellow colouring. When the silver content of sols increased, the same tendency is observed. Thermal densification of the sol–gel coatings have to be carried out under oxidising atmosphere, since heat-treatments performed under reducing atmosphere yielded grey-brownish colouring, due to reduction of the lead from the base glass. Optimum conditions for obtaining superficial yellow ruby colouring on lead crystal glass were selected.     

The Yellowing and Bleaching of Wool

The yellowing of wool is a complex phenomenon which is induced by a variety of agencies such as light, heat and aqueous chemical reactions. Yellowing of wool by light depends critically on the wavelength distribution of the light (u. v. region), humidity and the type of prebleach given to the wool; if fluorescent whitening agents (FWAs) are employed in the bleaching process then the sensitivity to photo-yellowing is drastically increased. The copious amount of work carried out to overcome this complex situation will be summarised and the important role of the aromatic indole amino acid, tryptophan, will be detailed. In contrast to photoyellowing, exposure of wool to visible blue light (maximal effect 420–450 nm) promotes photobleaching of the yellow pigments, giving rise to complaints of colour change, especially in wool products dyed to pastel colours. To remove natural yellowness, chemical bleaching of wool is usually carried out by using hydrogen peroxide, the usage of which should be carefully controlled because of its fibre damaging characteristics. Optimisation of wool peroxide bleaching procedures has therefore been the subject of much work and these studies will be reviewed. Bleaching of wool with reducing agents is often practised either as an alternative to peroxide bleaching or more usually as an aftertreatment of peroxide-bleached wool to improve the whiteness and stability to light. Trade practice in the field of wool bleaching has recently been critically reviewed; the results and recommendations of this assessment will be given. More recently, significant progress has been made in the field of selective dark fibre bleaching and in the bleaching of heavily pigmented wools (e.g. karakul) using methods based on ferrous ion mordanting.     

Structural and optical properties of diamond and nano-diamond films grown by microwave plasma chemical vapor deposition

We compare structural and optical properties of microcrystalline and nanocrystalline diamond (MCD and NCD, respectively) films grown on mirror polished Si(100) substrates by microwave plasma chemical vapor deposition. The films were characterized by SEM, Raman spectroscopy, XRD, and AFM. Optical properties were obtained from transmittance and reflectance measurements of the samples in the wavelength range of 200–2000 nm. Raman spectrum of the MCD film exhibits a strong and sharp peak near 1335 cm⁻¹, an unambiguous signature of cubic crystalline diamond with weak non-diamond carbon bands. Along with broad non-diamond carbon bands, Raman spectra of NCD films show features near 1140 cm⁻¹, the intensity of which is significantly higher in the film grown at 600°C compared to the NCD film grown at higher temperature. The Raman feature near 1140 cm⁻¹ is related to the calculated phonon density of states of diamond and has been assigned to nanocrystalline or amorphous phase of diamond. XRD patterns of the MCD film show sharp peaks and NCD films show broad features, corresponding to cubic diamond. The rms surface roughness of the films was observed to be approximately 60 nm for MCD film that reduced substantially to 17 and 34 nm in the NCD films grown at 600 and 700°C, respectively. Tauc's optical gap for the diamond film is found to be approximately 5.5 eV. NCD grown at 700°C has a high optical absorption coefficient in the whole spectral region and the NCD film grown at 600°C shows very high transmittance (∼78%) in the near IR region, which is close to that of diamond. This indicates that the NCD film grown at 600°C has the potential for applications as optical windows since its surface roughness is significantly low as compared to the MCD film.     

水性聚氨酯荧光增白材料的合成及其性能研究

荧光增白剂可吸收不可见的紫外光,并且将紫外光转变为可见的蓝色或蓝紫色光发射出来;由于蓝色和黄色互为补色,消除了物质中的黄色部分,从而达到了增白效果。因此,采用荧光增白剂合成的水性聚氨酯(WPU)增白材料,用于涂料和织物上,可初步解决芳香族WPU的耐黄变问题。研究了乳液pH值、荧光增白剂的用量及其添加方式对WPU增白效果的影响,并通过透射电镜(TEM)观察增白剂在WPU中的分散情况。实验结果表明,WPU乳液及其胶膜的蓝光效果随着荧光增白剂用量的增加呈先增后降的趋势,当w(荧光增白剂)=0.008%时为最佳;当pH=7～9时,荧光增白剂在WPU中的分散稳定性和增白效果都较好;荧光增白剂的两种添加方式对其在WPU乳液及其胶膜中的分散稳定性和增白效果的影响不明显。     

Fluorometric analysis of inertinite

In coal petrology, fluorescence microscopy has mainly been used in the study of liptinite (exinite) macerals. Recently, its scope of application has been widened to investigate vitrinite. This paper describes the conditions under which inertinite can also be studied by fluorometry. The method makes use of relatively long-wave excitation. Although the strongest signals are received through a green exciter filter at 546 nm, blue light excitation (450–490 nm) is preferred because the fluorescence spectrum is broader, the microscopic image more polychromatic and maceral identification is easier compared with longer-wave excitation. Inertinite macerals are divided into fluorescent and non-fluorescent constituents on the basis of both visual distinction and relative intensity determinations at 650 nm measuring wavelength. It appears that fluorescent inertinite corresponds closely to reactive fractions determined by previous coking experiments.     

涤纶用荧光增白剂

详细介绍了涤纶用荧光增白剂的主要品种及其使用方式,并通过几组实例证实了多组分荧光增白剂复配后对于涤纶的加和增效作用。简单评述了国内涤纶用荧光增白剂的生产现状、列出了国内的一些主要生产厂家及其产品,并预测了其发展前景。最后,提出了我国应该重视加和增效的研究,重视一些重要品种的开发,重视中间体的研究和工艺改进等几点建议。     

SHS of Eu2+-doped β-SiAlON phosphors: Impacts of N2 pressure and Si particle size

Self-propagation high-temperature synthesis (SHS) method was developed as a highly-efficient route for the preparation of Eu-doped β-SiAlON green phosphors. The as-synthesized products with composition Si_5.5Al_0.5O_0.5N_7.5:0.035Eu²⁺ were featured with high phase purity, good uniformity and equiaxed grain morphology. Strong green light emission spectra covering the range of 450–650 nm were obtained under the excitation of UV or blue light. The impacts of the nitrogen pressure in the reaction system and average particle size of Si reactant, which were two of the most vital parameters in the SHS reaction, were systematically investigated. Based on the experimental results, these two factors were confirmed to have striking influences on the phase composition, microstructure and photoluminescence properties of resultant phosphors. In the SHS for β-SiAlON:Eu²⁺ phosphors, there demonstrated that the selection of N₂ pressure of 4 MPa and the utilization of Si reactants with fine particle size would bring about remarkable enhancement in the photoluminescence properties.     

Spectroscopic behavior of poly(vinyl alcohol) films with different molecular weights after UV irradiation,thermal annealing,and double treatment with UV irradiation and thermal annealing

Pure poly(vinyl alcohol) (PVA) films with molecular weights 5,000, 72,000, and 125,000 g/mole were prepared by casting technique. The thickness of prepared samples was 0.21 mm. Xenon arc lamp was used to irradiate two samples from each molecular weight at 400 W for 5 min. One from each irradiated PVA samples was heated at 423 K for 2 h. An additional PVA sample unirradiated from each molecular weight was heated at 423 K for 2 h. Optical absorption measurements have been carried out in the wavelength range of 190–900 nm for untreated, UV‐irradiated, heated, and double‐treated samples by UV irradiation and heat. The double‐treated PVA samples with molecular weights 5,000 and 72,000 g/mole showed approximately zero transmission in comparison with untreated PVA sample in the wavelength range of 190–320 nm. PVA sample with 125,000 g/mole was irradiated with 600 W for 5 min to obtain the zero transmission in the same wavelength range. Identification of the structure and assignments of energy bands were studied also by using FTIR. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 589–594, 2003     

Tunable solid‐state fluorescence emission and red upconversion luminescence of novel anthracene‐based fluorophores

Novel, tunable solid‐state emitters based on anthracene groups were synthesised and characterised by spectroscopy and elemental analysis. Their solid‐state photoluminescence properties were studied. These fluorophores display interesting solid‐state emission properties with an emission at wavelengths ranging from 550 to 650 nm when excited by a 325 nm helium–cadmium laser at room temperature. In particular, among them, 1,6‐di(9‐anthryl)hexa‐1,5‐diene‐3,4‐dione, 2‐[4‐(2‐benzoxazolyl)phenyl]‐4,5‐bis[2‐(9‐anthryl)vinyl]‐1H‐imidazole and 2,3‐bis[2‐(9‐anthryl)vinyl]quinoxaline show red, yellow and green emission, respectively, at 650, 584 and 550 nm. The results demonstrated that the luminescent colours can be tuned from red to yellow and green by simply varying molecular structure. Besides, 1,6‐di(9‐anthryl)hexa‐1,5‐diene‐3,4‐dione also exhibited an upconverted red fluorescent emission peak at around 675 nm under femtosecond excitation at 800 nm.     

The role of copper and silver in the colouration of metallic luster decorations (Tunisia, 9th century; Mesopotamia, 10th century; Sicily, 16th century): A first approach

The metallic luster of glazed ceramics is a very special type of decoration. Its optical properties are characterized by a change of colour according to the observation conditions. In diffuse light, these decorations are often green, brown, or ochre‐yellow. In specular reflection, they show an associated coloured metallic reflection (blue, golden‐yellow, orange, etc.). Metallic copper and/or silver colloids almost always compose the metallic luster decorations. We wish to define the role of these two metals in the colouration observed both in diffuse light and in specular reflection. Our investigations show that a relationship exists between the proportions of copper and silver, and the diffuse colour. The green decorations contain more silver than copper, and the ochre‐yellow and brown decorations contain more copper than silver. This specific correlation only exists if the samples have the same type of glaze and, especially, a similar chemical composition. This means that the composition of the glaze has an important influence in the colouration process. Moreover, our investigations show that there is no relationship between the specular colour and the overall concentration of copper and silver. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 352–359, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10183     

Photochemical properties of sintered iron (III) oxide

The photochemical properties of vacuum deposited films and of sintered and doped iron(III) oxide have been studied. From the wavelength dependence of the photopotentials we know that photo-activity of the electrochemical cell with the iodine/iodide redox couple starts at the same wavelength, 600–650 nm, as the absorption of light and the photoconductivity of vacuum deposited films. Open circuit potentials of about 400 mV have been observed with the visible radiation from a 150 W xenon lamp. In neutral solution photocorrosion was too small to be observed.     

Optical and electrical characterization of (PEO+methyl violet) polymer electrolytes

Optical properties and electrical conductivity of polyethylene oxide (PEO) with methyl violet dopant film have studied. The complexation of the methyl violet dopant with PEO was confirmed by X‐ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopic studies. The microstructure morphology have been analyzed by scanning electron microscope (SEM) for pure and dopant films. The UV‐absorption studies were made in the wavelength range 190–1100 nm for pure and doped films. The dc electrical conductivity data was collected using two probe technique in the temperature range 303–333 K. The UV–visible spectra showed the absorption band at 190 nm for pure PEO and doped from 208–224 nm region with different absorption intensities. The absorption edge, direct and indirect band gap were estimated using Mott and Davis Model. The optical activation energy can be determined using the Urbach rule, for pure PEO it was found 2.38 eV and 1.28–4.08 eV for doped films. The absorption band was shifted toward the higher frequency, the direct and indirect band gap decreases with increasing of dopant concentration, corresponds to the allowed inter band transition of electron. The dc electrical conductivity results shows that it increases with increasing dopant weight percentage and temperature which corresponds to the enhancement of charge mobility in these dye doped polymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012