纳米掺钯WO3薄膜及气致变色性能研究

以钨粉和双氧水为原料，采用溶胶-凝胶技术结合提拉镀膜法，制备了纳米结构掺钯气致变色WO3薄膜；分析了薄膜的折射率、厚度、结晶度、红外特性和表面形貌随温度变化特性；研究了薄膜的气致变色性能。研究结果表明，纳米掺钯气致变色WO3薄膜有着良好的气致变色特性。重点讨论了薄膜结构、薄膜水含量以及薄膜钯含量对薄膜变色效率的影响。     

电致变色纳米氧化镍薄膜的溶胶-凝胶法制备与表征

以无水氯化镍、乙醇为前驱液,加入适量的丁醇和柠檬酸为稳定剂,通过回流、水解得到稳定的溶胶;采用浸渍-提拉的方法在ITO导电玻璃上形成均匀的膜层;分析了溶胶制备中加水量的影响;研究了热处理温度对制备膜层的结构、光透过率的影响;对经过不同处理的膜层进行X射线衍射、透射电子显微镜、扫描电子显微镜、热重分析等研究表明:在空气中加热到350℃、保温30min薄膜分解为稳定的具有立方结构的NiO纳米晶;以氢氧化钾水溶液为电解质的循环伏安、电致变色实验结果表明制备的纳米氧化镍薄膜具有良好的电致变色特性.     

SiO2纳米复合稳定WO3薄膜气致变色特性研究

以钨粉为主要原料,采用过氧化法及提拉技术制备WO3薄膜,通过SiO2纳米颗粒复合改性提高了WO3薄膜的气致变色稳定性.测试并研究了SiO2复合掺杂对溶胶颗粒分布、气致变色稳定性等的影响,通过测试薄膜循环中红外振动吸收的演变,深入研究了SiO2纳米复合对WO3薄膜气致变色性能影响的内在机制.研究结果表明,SiO2的掺杂抑制了WO3薄膜内的共角聚合,将薄膜的致/褪色循环次数由20次提高到500次以上,WO3-SiO2复合薄膜的稳定网络结构是提高其气致变色循环稳定性的主要原因.     

纳米氯化银/壳聚糖抗菌敷料的制备及功能评价

以壳聚糖纤维为基底材料,经表面处理,采用硝酸银多步浸渍和快速氯化反应的方法,制备均匀嵌合纳米氯化银颗粒的壳聚糖纤维复合抗菌敷料。银负载量小于60mg/10*10cm2时,壳聚糖纤维表面可观察到均匀的氯化银纳米粒子,粒径分布20~80nm。氯化银纳米粒子结构和抑菌性具良好的稳定性,对大肠杆菌、金黄色葡萄球菌和绿脓杆菌的抑菌率均可达到99.99%。氯化银纳米粒子在经预处理的壳聚糖纤维表面具有良好的固着性。纳米氯化银/壳聚糖纤维供试样品对深二度烧伤伤口愈合没有不良作用,相对于生理盐水/纱布和磺胺吡啶银/纱布对照组,供试样品组的愈合率更高。本研究成果为新型氯化银抗菌敷料研发提供了重要依据。     

NiOxHy纳米电致变色薄膜的制备和表征

采用溶胶-凝胶的方法制备了NiOxHy纳米电致变色薄膜;对比了不同稳定剂(柠檬酸、正丙醇、正丁醇、异丁醇、正戊醇和正己醇)对致色效果的影响;讨论了溶胶制备过程中投料比和温度的影响.最后,对制备的NiOxHy薄膜的性能进行了表征.     

掺钯纳米WO3薄膜气致变色窗研究

报道了以钨粉和H2O2为原料,采用溶胶凝胶技术和旋转镀膜方法,制备出掺钯气致变色WO3纳米薄膜;使用两块普通玻璃,其中一块内侧涂膜,做成四边封合中空气致变色窗,通以稀薄H2获得最佳致色响应时间小于10 s,在2 min之内700nm波长处的透过率变化超过60%.研究了热处理温度、催化剂钯掺量、薄膜厚度对薄膜特性的影响.     

塑料基TiO2电致变色薄膜制备及性能研究

采用溶胶-凝胶法分别在镀有ITO透明电极的玻璃和塑料基体上制备了TiO2电致变色薄膜,对比研究了不同基体上溶胶的成膜性及薄膜的电致变色性能.结果表明:在相对湿度低于15%的环境中,采用0.4mol/L的溶胶可以通过多次提拉制得表面光洁的较厚透明TiO2薄膜;随热处理温度的升高,薄膜的电色可逆性变好,循环寿命变大,但离子储存能力下降;塑料基TiO2薄膜与相同条件下制备的玻璃基薄膜具有相似的性能,呈现出较弱的阴极电致变色效应和较强的Li 储存能力,有望用作柔性电致变色器件的对电极.     

TiO2,MoO3,PEO掺杂的四元钨酸溶胶的稳定性研究

首次制备了TiO2,PEO,MoO3掺杂的四元钨酸溶胶,用旋转粘度计研究了不同配方掺杂的钨酸溶胶稳定性,筛选出了最佳配方,该配方制备的四元掺杂的钨酸溶胶在室温下可以稳定保存两个月以上.由该配方钨酸溶胶制的WO3电致变色薄膜材料的成膜均匀,性能优良.     

WO3纳米薄膜的制备与气致变色特性研究

报道了以钨粉为原料，采用溶胶一凝胶技术和旋转镀膜方法，制备出了气致变色WO3纳米薄膜。采用椭偏仪、X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、红外光谱仪以及可见光分光光度计等方法分析了薄膜的特性。研究结果表明热处理使得薄膜致密，折射率增大，厚度减小，薄膜结晶；过氧键消失，WO3微结构发生了变化，共角W-O-W键吸收越来越强，且向高波数方向移动。这些变化归因于热处理导致的WO3颗粒形状、团聚状态的变化以及应变键的产生。WO3纳米薄膜具有很好的气致变色特性，致色与退色态透射率变化超过60％，变色起因于H扩散到WO3薄膜中形成的小极化子吸收。     

木质基光敏变色功能材料的变色性能研究

利用聚乙烯醇作载体,通过溶胶-凝胶使光敏变色材料与实体木材进行复合,制备具有在紫外光照射下能发生光敏变色的木质基功能材料。通过紫外光辐射前后色度指数、视觉效果比较分析了紫外光照射对木质基光敏变色功能材料表面色差指数的影响。结果表明,经紫外光辐射后材料表面色差值明显增加,光敏变色效果显著。     

Large-scale synthesis of silver nanowires via a solvothermal method

Silver nanostructures have been synthesized through a simple solvothermal method by reducing silver nitrate (AgNO₃) with ethylene glycol (EG) and using poly(vinylpyrrolidone) (PVP) as an adsorption agent. Different concentrations of ferric chloride (FeCl₃) are added into the solution. It is found that AgCl colloids formed in the initial stage greatly influence the final morphologies of the products. When a low-concentration FeCl₃ solution is used, there is a mixture of silver nanoparticles and nanowires. However, when a high-concentration FeCl₃ solution (100 μM) is used, large amounts of AgCl colloids appear, resulting in decreasing free Ag⁺ during initial formation of silver seeds and slowly releasing of Ag⁺ to the solution in the subsequent reaction. This leads to the formation of silver nanowires. Furthermore, an increase in the concentration of FeCl₃ from 100 to 300 μM results in the synthesis of silver nanowires with larger sizes. In addition, Fe(III) is reduced to Fe(II) form which in turn reacts with and removes adsorbed atomic oxygen from the surface of silver seeds. In this case, uniform silver nanowires can be obtained.     

Morphology-controlled synthesis of silver nanostructures via a solvothermal method

Silver nanostructures have been synthesized by a simple solvothermal method in the presence of poly(vinylpyrrolidone) (PVP). Typically, different exotic agents (NaOH, KBr, NaCl) are added into the reaction system. The anions (OH⁻, Cl⁻, Br⁻) from these agents can combine Ag⁺ to form silver salt colloids (AgOH, AgBr and AgCl), decreasing the concentration of free Ag⁺ in the initial formation of silver seeds. However, different release rates of Ag⁺ from these colloids to the solution in the subsequent reaction may play different roles in the growth of silver seeds. The as-prepared silver nanostructures were characterized by UV–vis absorption spectrum, X-ray diffraction (XRD) and field emission scanning electron microscope (FSEM). It is found that silver nanostructures with various shapes can be obtained by the addition of different exotic agents. Finally, our work provides a simple route to synthesize silver nanostructures with controllable morphologies.     

Uniform Ag Nanocubes Prepared by AgCl Particle–Mediated Heterogeneous Nucleation and Disassembly and Their Mechanism Study by DFT Calculation

Uniform Ag nanocubes are reproducibly synthesized by a AgCl particle‐mediated heterogeneous nucleation and disassembly process in polyol chemistry. By introducing N,N‐dimethylformamide (DMF) in a conventional polyol method with HCl etchant, Ag nanocrystals (NCs) begin to be nucleated on the surface of AgCl‐precipitated particles due to the promoted reduction reaction by DMF. The nucleated Ag NCs on the AgCl particles are grown to Ag nanocubes in shape by consuming Ag sources from the AgCl mother particles. Eventually the grown Ag nanocubes are disassembled from the mother AgCl particles because the AgCl particles are fully digested by the growing Ag nanocubes. Density functional theory calculation confirms that the Ag atoms can be favorably deposited on the (100) facet of AgCl particles and the Ag nuclei on the AgCl particles tend to reveal (100) facet.     

纳米AgCl水溶胶的制备与表征

采用沉淀法制备了AgCl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,AgCl纳米粒子呈球形,粒径小于30 nm,粒度分布均匀,无明显团聚现象;ED分析表明,AgCl纳米粒子为多晶结构,其中有少量的发育较好的单晶颗粒存在.     

Latent Image Formation at High Intensity Exposures in Photographic Emulsions

After a critical review of some important literature data on reciprocity law failure at high intensity exposures (HIRF) we discuss recent experimental results about HIRF in AgCl relative to AgBr fine grained model emulsions in the primitive, sulphur (S), gold (Au) and gold + sulphur (Au + S) sensitized state. Influence of the pAg during ripening on HIRF is also outlined.

Although some results are qualitatively equal on both silverhalides, there are nevertheless important quantitative differences as for example the greater effectiveness of Au in the AgCl emulsion. Interpretation of the differences is based on the idea of the stronger catalytic activity of sensitivity specks to reduce AgCl in comparison with AgBr. Recent results are also mentioned concerning the mechanism of the TAI action (Tetra-Aza Indene) in AgCl and AgBr emulsions at different intensity exposures.     

Characterization of overoxidized polypyrrole colloids imprinted with L-lactate and their application to enantioseparation of amino acids

Overoxidized polypyrrole colloids imprinted with L-lactate were prepared to evaluate the performance of the overoxidation pseudo-template technique developed by the authors. A polypyrrole colloid that had been prepared from a mixture of monomer (pyrrole), dopant (L-lactate), steric stabilizer (poly(vinylpyrrolidone)) and oxidizing agent (peroxodisulfate) was electrochemically overoxidized at +1.5 V vs Ag/AgCl to create a complementary cavity for recognition of the molecules, which were structurally similar to dopant, through dedoping. As a target molecule for enantioselective uptake into the overoxidized colloid, we selected alanine, which is structurally different from the template (lactate) only in one side chain (alanine, -NH2; lactic acid, -OH). The overoxidized polypyrrole colloid showed higher affinity for L-alanine than for D-alanine, and an uptake ratio (L/D) of as high as 11 +/- 4 was observed under optimum conditions. Uptake reached equilibrium in 10 min, thanks to the high surface area and short diffusion length in the colloidal particle. Further, to confirm the complementarity of the cavity, the effect of side chain size on uptake of several alpha-amino acids was examined to indicate that the uptake amount decreased with increasing molecular volume of the L-amino acids.     

Multifunctional Assembly of Micrometer‐Sized Colloids for Cell Sorting

Compared to the extensively studied nanometer‐sized colloids, less attention has been paid to the assembly of micrometer‐sized colloids with multifunctional characteristics. To address this need, a bottom‐up approach is developed for constructing self‐assemblies of micrometer‐sized magnetic colloids possessing multifunctionality, including magnetic, optical, and biological activities. Biotinylated oligo (p‐phenylene vinylene) (OPV) derivatives are designed to mediate the self‐assembly of streptavidin‐modified magnetic beads. The optical element OPV derivatives provide a fluorescence imaging ability for tracing the assembly process. Target cells can be recognized and assembled by the colloidal assembly with bioactive element antibodies. The colloidal assembly reveals better cell isolation performance by its amplified magnetic response in comparison to monodisperse colloids. The self‐assembly of micrometer‐sized magnetic colloids through a combination of different functional ingredients to realize multifunction is conceptually simple and easy to achieve.     

Non‐Equilibrium Assembly of Light‐Activated Colloidal Mixtures

The collective phenomena exhibited by artificial active matter systems present novel routes to fabricating out‐of‐equilibrium microscale assemblies. Here, the crystallization of passive silica colloids into well‐controlled 2D assemblies is shown, which is directed by a small number of self‐propelled active colloids. The active colloids are titania–silica Janus particles that are propelled when illuminated by UV light. The strength of the attractive interaction and thus the extent of the assembled clusters can be regulated by the light intensity. A remarkably small number of the active colloids is sufficient to induce the assembly of the dynamic crystals. The approach produces rationally designed colloidal clusters and crystals with controllable sizes, shapes, and symmetries. This multicomponent active matter system offers the possibility of obtaining structures and assemblies that cannot be found in equilibrium systems.     

Atomistic and mesoscale interface simulation of graphite nanosheet/AgCl/polypyrrole composite

Interfaces of graphite nanosheet/AgCl/Polypyrrole (NanoG/AgCl/PPy) composite have been researched by atomistic and mesoscale simulations. The results showed that the three-component nanocomposites were formed on the basis of van der Waals interfacial interactions between two components (except between NanoG and AgCl). PPy played a key role of adhesive, which combine with NanoG and AgCl separately through strong advantaged interfaces. So the three-components could form nanocomposite as a whole in mesoscale. Quantitative analysis of density and potential distributions of NanoG/AgCl/PPy composites showed that they had proper potential interfaces and uniform distribution. The NanoG well dispersed in PPy matrix, and the matrix was decorated by core–shell nanoparticles with AgCl as the core and PPy as the conducting shell.