云母表面不同厚度VO2薄膜的红外光学特性

以天然白云母的解理面为基底,采用无机溶胶-凝胶法在其表面制备不同厚度的VO2薄膜,并研究了厚度对VO2薄膜的微观结构和红外光学特性的影响.利用SEM、XRD等手段分析了薄膜的表面形貌和晶体结构,利用原位FTlR分析了VO2薄膜半导体-金属相变特性.结果表明,云母表面VO2薄膜室温下具有(011)择优生长取向,随着厚度增...     

VO_2热色智能玻璃研究进展

二氧化钒(VO2)是一种受人关注的热致变色材料,在68℃时发生从半导体相-金属相的转变,且相变可逆。在介绍智能玻璃在建筑节能中潜在应用的基础上,重点阐述了VO2纳米薄膜应用于智能型节能玻璃的国内外研究进展。较全面地论述了利用光学减反射技术提高VO2智能玻璃可见光透过率的技术现状。总结了VO2智能玻璃在实际应用中存在的技术难点:节能效率偏低、薄膜沉积温度高、外观颜色不美观、保温性能上的缺陷等。展望了VO2智能玻璃的研究与应用前景。     

低温可逆示温涂料及性能的研究

介绍了以Ag2HgI4为变色颜料,不同的无机材料作为填料,研制成低温可逆示温涂料的工艺流程;通过该系列示温涂料的变色温度、复色时间等性能实验,探讨了不同类型的填料对示温涂料性能的影响,并确定了最佳配方。     

二氧化钒纳米周期点阵的光学特性

为了得到相变温度低且性能优越的智能窗光学材料,基于时域有限差分法模拟计算了不同结构的VO_2纳米周期点阵相变前后的光学特性,优选出最佳的VO_2纳米周期点阵结构.采用直流磁控溅射和后退火工艺在玻璃衬底上制备VO_2薄膜,再利用掩膜光刻的方法制备VO_2纳米周期点阵结构,测试其组分结构,反射和透过率曲线.结果表明,填充比为0.74的圆形纳米周期点阵的相变温度有效降低了约25℃,在波长为1700 nm处的透过率改变量达到39%,透过率整体高于VO_2薄膜,呈现出良好的相变光学特性,说明通过调控VO_2纳米周期点阵的结构可以有效提升材料的光学特性.     

可逆热致变色涂料印花研究

采用可逆热致变色涂料对织物进行印花.研究增稠剂、粘合剂、焙烘条件等对织物颜色、牢度等的影响.结果表明, 微胶囊包封后, 体系内可能遗留部分未反应的环氧树脂与固化剂残基, 这些基体有可能与印花粘合剂、增稠剂发生反应而生成不透明物质, 从而影响色浆及印花产品的颜色, 所以印花助剂的选择和工艺条件的控制十分重要.在本研究范围内, 最佳色浆配方和印花工艺条件为: 耐盐性能和抗渗化性能好的KG-201、 KG-203作增稠剂;对颜色影响小且手感好的PT-528S作粘合剂, 用量为色浆的15%, 焙烘条件是100℃下5min.     

溴甲酚绿-稀土配合物的热变色性能及变色机理

以稀土金属离子(La3+、Ce3+和Nd3+等)为显色剂,溴甲酚绿为发色剂和配位剂,制备了一系列稀土配合物可逆热变色材料,测试其综合变色性能,讨论了显色剂种类及用量、溶剂用量对稀土配合物热变色性能的影响。FT-IR、UV-Vis和DSC测试结果表明,热变色机理可归结为分子间的电子得失,随着温度变化,溴甲酚绿的结构在内酯式和醌式之间转变,颜色随之改变。     

Crystallization‐Induced Emission Enhancement of a Deep‐Blue Luminescence Material with Tunable Mechano‐ and Thermochromism

Organic luminescent materials with the ability to reversibly switch the luminescence when subjected to external stimuli have attracted considerable interest in recent years. However, the examples of luminescent materials that exhibit multiresponsive properties are rarely reported. In this work, a new stimuli‐responsive dye P1 is designed and synthesized with two identical chromophores of naphthalimide, one at each side of an amidoamine‐based spacer. This amide‐rich molecule offers many possibilities for forming intra‐ and intermolecular hydrogen bond interactions. Particularly, P1 has an intrinsic property of cocrystallizing with methanol. Compared with the pristine P1 sample, the as‐prepared two‐component cocrystalline material displays an exceptive deep‐blue emission, which is extremely rare among naphthalimide‐based molecules in the solid state. Furthermore, the target material exhibits an obvious mechanochromic fluorescent behavior and a large spectral shift under force stimuli. On the other hand, the cocrystalline material shows an unusual “turn off” thermochromic luminescence accompanied by solvent evaporation. Moreover, using external stimuli to reversibly manipulate fluorescent quantum yields is rarely reported to date. The results demonstrate the feasibility of a new design strategy for solid‐state luminescence switching materials: the incorporation of solvents into organic compounds by cocrystallization to obtain a crystalline state luminescence system.     

水合对硝基苯酚的热色性研究

对硝基苯酚是没有热色性的物质,本工作在水溶液中合成了水合对硝基苯酚,且培养出单晶。该结晶水合物表现出可逆的热色性,当加热到140℃时,它会由橙红色变为明亮的红色;随着温度缓慢降低,其颜色也恢复为原来的橙红色。差示扫描量热法(DSC)分析证实了这一观察到的现象。热重分析(TG)测试显示该结晶水合物颜色的变化是由于水合和失水而导致的。     

Hydrothermal Synthesis of VO2 Polymorphs: Advantages,Challenges and Prospects for the Application of Energy Efficient Smart Windows

Vanadium dioxide (VO₂) is a widely studied inorganic phase change material, which has a reversible phase transition from semiconducting monoclinic to metallic rutile phase at a critical temperature of τ_c ≈ 68 °C. The abrupt decrease of infrared transmittance in the metallic phase makes VO₂ a potential candidate for thermochromic energy efficient windows to cut down building energy consumption. However, there are three long‐standing issues that hindered its application in energy efficient windows: high τ_c, low luminous transmittance (T_lum), and undesirable solar modulation ability (ΔT_sol). Many approaches, including nano‐thermochromism, porous films, biomimetic surface reconstruction, gridded structures, antireflective overcoatings, etc, have been proposed to tackle these issues. The first approach—nano‐thermochromism—which is to integrate VO₂ nanoparticles in a transparent matrix, outperforms the rest; while the thermochromic performance is determined by particle size, stoichiometry, and crystallinity. A hydrothermal method is the most common method to fabricate high‐quality VO₂ nanoparticles, and has its own advantages of large‐scale synthesis and precise phase control of VO₂. This Review focuses on hydrothermal synthesis, physical properties of VO₂ polymorphs, and their transformation to thermochromic VO₂(M), and discusses the advantages, challenges, and prospects of VO₂(M) in energy‐efficient smart windows application.     

Quantification of response time in poly(vinyl alcohol)–metal complex thermochromic polymeric systems

Thermochromic poly(vinyl alcohol) (PVA)‐based material was synthesized and an extensive study of its thermochromic behavior with respect to response time was carried out. It was observed that it is possible to manipulate the response time by keeping control over chemical and physical parameters. The response time, which is the most important property of a smart material, has in this case been found to be very much influenced by rate of heat transfer into the material. Different compositions of the thermochromic material and their corresponding response time with respect to rate of heat transfer were studied and correlated. First, a theoretical equation was derived and later on it was experimentally verified to quantify the response time in PVA–metal complex‐based thermochromic systems. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4832–4834, 2006