MoO3纳米粒子水溶胶的制备与光致变色性质研究

采用沉淀法制备了MoO3纳米粒子水溶胶,对制备水溶胶的条件进行了系统地研究.TEM分析表明,MoO3纳米粒子呈球形,粒径约为60nm,粒度分布均匀;ED分析表明,MoO3纳米粒子为多晶结构.UV-VIS分析表明,MoO3纳米粒子水溶胶具有一定的光致变色特性.     

Effect of drawing ratio on difference in optical density and mechanical properties of mass colored photochromic polypropylene filaments

Photochromic textiles have been used in the sensible materials (sensor) in the smart textiles and esthetic materials in the fashion industry due to the color changing properties, which gives immense inspiration to prepare photochromic textile materials, in this regards we take more attention to prepare the mass dyed polypropylene filaments with photochromic pigments. Metallocene polypropylene filaments were doped by different concentration of photochromic pigment. In our experimental work, the optical and mechanical properties of these multifilaments depending on their drawing ratio were investigated. The photochromic pigment used was 5-Chloro-13-dihydro-133-trimethylspiro[2H-indole-23′-(3H)naphtha [2,1b](14)oxazine]. Regarding the optical properties, our investigation confirms the known effect of the primary reflectance on the depth of shade of colored multifilaments as shown by linear increase in difference in optical density with increasing ratio of fineness.     

光致变色介孔二氧化硅/磷钼酸复合薄膜的制备与性能

利用蒸发诱导自组装和后植入的方法,制备出了在紫外光照下可变色的二氧化硅/磷钼酸复合薄膜.结果表明,磷钼酸粒子很好的分散并牢牢附着在有机胺改性的二氧化硅介孔薄膜的孔道中;经紫外光照后发生电荷转移,杂多阴离子被还原成杂多蓝,由无色变成蓝色,而薄膜的褪色过程则与氧气存在有关.     

光致变色俘精酸酐用于可擦写全息图像存储的研究

对一种新型可擦重写有机光致变色材料——俘精酸酐／聚甲基丙烯酸甲脂(PMMA)薄膜的光致变色双稳态吸收光谱进行了测量，呈色态的吸收峰在513nm，无色态的吸收峰在370nm。利用该双稳态特性，在10μm俘精酸酐／PMMA薄膜上进行全息图像光存储。实验用氩离子激光器514．5nm波长作为记录光源，测量了衍射效率与曝光量的关系，最大衍射效率约为1％．最佳曝光量约1J／cm^2。获得了存储于样品上的全息干涉条纹和参考光再现的衍射像，分析了影响衍射图像像质的因素。记录在样品上的全息图在室温下黑暗处可以保存一年以上，用紫外光可以擦除记录的全息图．进行多次记录、读出和擦除操作。结果表明，俘精酸酐可以作为一种性能优良的可擦写全息光存储材料。     

Reversible Switching of Spiropyran Molecules in Direct Contact With a Bi(111) Single Crystal Surface

Photochromic molecular switches immobilized by direct contact with surfaces typically show only weak response to optical excitation, which often is not reversible. In contrast, here, it is shown that a complete and reversible ring‐opening and ring‐closing reaction of submonolayers of spironaphthopyran on the Bi(111) surface is possible. The ring opening to the merocyanine isomer is initiated by ultraviolet light. Switching occurs in a two‐step process, in which after optical excitation, an energy barrier needs to be overcome to convert to the merocyanine form. This leads to a strong temperature dependence of the conversion efficiency. Switching of the merocyanine isomer back to the closed form is achieved by a temperature increase. Thus, the process can be repeated in a fully reversible manner, in contrast to previously studied nitrospiropyran molecules on surfaces. This is attributed to the destabilization of the merocyanine isomer by the electron‐donating nature of the naphtho group and the reduced van der Waals interaction of the Bi(111) surface. The result shows that molecules designed for switching in solutions need to be modified to function in direct contact with a surface.     

光致变色材料的研究与应用

变色材料在变色眼镜、光学信息存储、光分子开关等方面具有广泛的应用.主要分析了螺吡喃、俘精酸酐、二芳基乙烯以及二氧化钛、卤化银等有机和无机光致变色材料的研究现状及其变色机理,最后介绍了光致变色材料在国防以及信息存储材料等方面的应用前景.     

Electrochromically and Photochromically Controllable Multifunctional OligoEDOT Derivatives

Multifunctional conjugated co‐oligomers with electrochromic and photochromic properties are synthesized by a cross‐coupling polycondensation reaction between bis(trialkylstannyl)‐3,4‐ethylenedioxythiophene and a phenylene or thienylene derivative bearing a photoresponsive dithienylethene (DE) moiety. The oligomer exhibits a reversible change between the neutral and oxidized states of the main chain upon electrochemical doping and dedoping. Furthermore, the oligomer shows reversible photoisomerization between the open and closed forms of the DE group in the side chain upon irradiation with ultraviolet and visible light. As a consequence, the oligomers possess various electronic structures that show cyclically reversible changes via the electrochemical doping and dedoping, and photoisomerization, producing four types of colored films in an oligomer system. Among the four types of electronic structures, only the dopant‐free oligomer film with the open form of the DE group shows visible fluorescence. To the best of our knowledge, the present conjugated oligomers are the first to exhibit both electrochromic and photochromic functions with cyclical reversibility.     

Synthesis and properties of photochromic cholesteric liquid crystalline polysiloxane containing chiral mesogens and azobenzene photochromic groups

A series of novel thermotropic side‐chain liquid crystalline polymers(P₀–P₁₂) were synthesized by grafting copolymerization of mesogenic monomer cholesteryl undecylenate (M1) and photochromic monomer 4‐allyoxy‐4′‐nitroazobenzene (M2) on polymethylhydrosiloxane. The chemical structures of polymers were characterized by infrared (IR) and ultraviolet (UV) spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to measure the thermal properties of those polymers, and the mesogenic properties were characterized by polarized optical micrograph, DSC, wide‐angle X‐ray diffraction and small‐angle X‐ray scattering. The glass transition temperatures (T_gs) of the polymers increased from P₀ to P₄ and decreased from P₅ to P₁₂. The clearing point temperatures (T_is) of the polymers P₁–P₁₂ were lower than that of P₀, but increased from P₁ to P₄ and decreased from P₅ to P₁₂. They showed thermotropic liquid crystalline properties in a broad mesogenic region at temperatures >100°C. The polymers P₀–P₈ exhibited a cholesteric mesophase with oily streaks and lined texture, and polymers P₉–P₁₂ showed a chiral smectic mesogenic phase with a layered texture. All of the polymers were thermally stable to ～ 320°C. The UV‐induced trans–cis photoisomerization was investigated for the azo monomer and polymers P₈ and P₁₂. The solution of the azo monomer and liquid crystalline polymers P₈ and P₁₂ can undergo photoisomerization, and the environments of the azo group were responsible for the aforementioned photochemical process. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2155–2162, 2002