Deposition of Layer－by－layer Inorganic－organic Nano－hybrid Ultrathin Films onto SBA－15

Deposition of inorganic-organic nano-hybrid ultrathin films onto mesoporous silicate materials has been proven possible by using layer-by-layer assembly method. In combination with sol-gel method, titania, subsequently dye molecules (or polymer) were successfully fabricated onto the inner wall of SBA-15. Their structures were preliminarily characterized by FTIR and solid-state UV-Vis spectroscopy, thermal analysis, and BET surface area measurements,respectively.     

纳米自组装聚电解质超薄多层膜

相反电荷的聚电解质在溶液中通过静电相互作用自组装形成超薄多层膜，这种膜的结构可实现分子水平上的控制。就其复合、结构及其影响因素、以及应用进行了概述。     

Optical Properties of Noble Metal Clusters in Ultrathin Solid Films

We report on the optical properties (absorption, Raman response) of thin and ultrathin phthalocyanine and amorphous silicon films with incorporated noble metal clusters. The metal clusters cause the typical absorption features originating from their surface plasmon resonance. In ultrathin films, due to the spatially close interface, the plasmon absorption may be displaced from its resonance frequency in the bulk, and its average position may be controlled by the average thickness of the ultrathin optical film. For example, we observe a shift of the plasmon resonance of silver clusters in amorphous silicon films (on fused silica) from 440 nm to 740 nm, when the silicon thickness increases from zero up to 9 nm. The deposition experiments are accompanied by investigations of the film structure, particularly in order to estimate the silver cluster diameter, which is around 3 nm or less.     

Hofmeister Salts Affect Buildup of Thin Multilayer Films Surrounding Oil Droplets

The layer-by-layer electrostatic deposition method is a novel technique to precisely control the interfacial properties of multilayered films such as charge, thickness, permeability, and composition. The formation and stability of multilayered emulsions is however often plagued by extensive droplet flocculation and aggregation even at ideal polyelectrolyte concentrations where saturation should occur. Addition of salts may reduce the degree of attractive interactions ions and thus improve deposition. To test this hypothesis, the influence of different Hofmeister salts (KCl, NaCl, LiCl, and NH₄Cl) at various salt concentrations (0–2500 mM) on the aggregation behavior of multilayered emulsions was investigated. A simple coating process of fish gelatin interfacial membranes with sugar beet pectin was used. Our results show that mean particle diameter and particle size distribution of emulsions initially decreased from 600 nm to 328 nm with increasing salt concentrations up to 250 mM. Above a critical level (>500 mM), heavy aggregation of emulsions at the presence of chaotropic salts occurred whereas kosmotropes reduced flocculation and creaming. Microscopic images and isothermal titration calorimetry confirmed particle size measurements. Results thus suggest that addition of salts may be an extremely useful tool to modulate and improve depositioning of alternatingly charged polymers on surfaces.      

Keggin型铬取代杂多阴离子/D301R可见光催化性能

将Keggin型铬取代磷钨杂多阴离子PW11O39Cr(Ⅲ)(H2O)4-(PW11Cr)负载于弱碱性阴离子交换树脂D301R表面,制备了固体光催化剂PW11Cr/D301R,并以模型污染物罗丹明B(RhB)的降解为探针评估了该催化剂的可见光催化活性,讨论了光催化反应机理,同时考察了催化剂剂量、溶液pH值和溶液中常见离子对RhB可见光催化降解反应的影响以及催化剂的稳定性。 实验结果表明,当PW11Cr/D301R的剂量为100 mg时,10 μmol/L RhB水溶液暴露在200 W金卤灯下进行照射,RhB完全降解所需的时间仅为30 min,比PW11Cr均相体系缩短了3倍;反应180 min总有机碳(TOC)去除率约为84%。 催化剂剂量、溶液pH值和溶液中存在的Cl-、SO2-4和PO3-4对RhB光催化降解反应的速率均有一定影响。 催化剂循环实验显示经循环使用7次后催化剂的活性几乎没有损失。     

基于过渡金属离子与三联吡啶的配位作用构筑全共轭层-层 自组装超薄功能膜

本文利用所合成的4'-（4''-重氮基）苯基-（2,2':6',2'）-三联吡啶氟硼酸盐（Diazo-tpy）在紫外光照射下的光分解反应特性,实现三联吡啶基团与基片之间形成共轭价键连接,这不仅提高了自组装膜的稳定性,而且降低了载流子在两者之间传输时的阻抗;在此基础上,通过两端含三联吡啶的直线型配体1,4-二-(2,2':6',2'-三联吡啶)基苯（Bi-tpy）与四种过渡金属离子（Mtn+：Pt4+、Ru3+、Rh3+、Pd2+）之间的配位作用,通过层－层自组装制备了全共轭金属－有机自组装超薄功能膜。由紫外-可见光谱跟踪自组装过程证明了自组装过程的成功实现,还分析了金属离子的种类对自组装的影响规律。光电转换测试表明Bi-tpy/Ru3+自组装膜要比Bi-tpy/ Pt4+具有更明显的光电转换性能;同时,由于缺陷与阻抗随层数的增加而增大的原因,在自组装6层时光电流达到最大值。这为我们设计新型光电转换器件提供参考依据。     

Fabrication of Layer-by-layer Films of Polyhedral Oligomeric Silsesquioxanes

Layer-by-layer(LBL)self-assembly method was used to fabricate siliceous ultrathin films by using polyhedral oligomeric silsesquioxanes as building blocks.Ammonium salt of kctasilsesquioxane acid (OSi8) and bply(diallyldimethylammonium chloride)(PDDA) were altermately assembled onto CaF2 slide to form nanocomposite multilqyers,Linear build-up of the LBL films was confirmed by UV-Vis spectroscopy.IR spectrum suggests existence of OSi8 and PDDA in the LBL films.Atomic force microscopic surface topography of the LBL films indicates the OSi8 covers the entire surface of the topmost layer and shows a granular morphology.     

Electrochemical and Surface Properties of Multilayer Films Based on a Ru2+ Metallodendrimer and the Mixed Addenda Dawson Heteropolyanion

The successful formation of organized multilayer assemblies, formed from the Dawson type mixed addenda heteropolyanion, [P₂W₁₇ V^IVO₆₂]^8?, and a Ru²⁺ pentaerythritol based metallodendrimer, [RuDen]⁸⁺, has been achieved on carbon electrode surfaces. Cyclic voltammetric studies of the assembly across a wide pH domain, namely, 2 to 7 was possible. Upon redox switching, the redox couples associated with the Ru^III/II redox system, of the cationic metallodendrimer, and both the V^IV/V and the tungsten‐oxo framework of the heteropolyanion, were clearly evident. The multilayer assembly exhibited good stability towards both redox cycling and soaking over extended periods of time in aqueous buffer solutions. In addition, the constructed multilayer films were found to be quite compact in nature. The films were further characterized by X‐ray photoelectron spectroscopy (XPS) to determine their elemental composition. Surface morphology of the multilayer films was determined by atomic force microscopy (AFM). The electrocatalytic reduction of iodate by the multilayer film was also investigated.     

聚乳酸自支持膜的叠加及其作为药物控释阻隔层的研究

发展了一种将自支持膜层层叠加制备多层膜的新方法,并研究了该薄膜对药物释放的调控效果. 首先利用聚乙烯醇作为牺牲层制备出聚乳酸自支持膜,然后将聚乳酸自支持膜转移或层层叠加到载药薄膜表面,最后对覆盖有聚乳酸薄膜的载药膜进行药物释放研究. 实验结果表明,聚乳酸薄膜对药物的释放起到了明显的调节作用,并且转移的薄膜的控释效果优于原位制备的薄膜,多层叠加的薄膜控释效果强于同等厚度的单层薄膜. 这可能是由于转移和叠加的薄膜层与层之间的空隙对药物的释放起到了缓冲作用所致. 这种基于自支持膜叠加制备多层膜的方法为药物涂层的研究提供了新思路,在生物材料、医用植入器件等领域都有一定的发展前景.     

D301R树脂对Keggin型铁取代杂多阴离子的吸附性能研究

详细研究了D301R弱碱性阴离子交换树脂对Keggin型铁取代杂多阴离子PW11O39Fe(III)(H2O)4－ (PW11Fe)的吸附作用, 考察了不同pH和温度对吸附量和吸附速率的影响, 测定了不同温度下吸附的动力学曲线和吸附等温线, 提出吸附动力学模型和计算了吸附的热力学函数, 结果表明, 在pH 2～8的范围内, PW11Fe的吸附量随溶液pH值的升高而增加, 随溶液温度的升高而降低; 吸附动力学符合表面过程控制的准二级反应模型, 其速率常数k2在298 K时为 9.33×10－4 g•mg－1•min－1, 并随温度的升高而减小. 吸附等温线符合Freundlich吸附模型, 吸附热约为40 kJ•mol－1, 因此, 吸附为物理吸附.     

基于血红蛋白/硒化镉量子点多层膜的H2O2生物传感器

合成了水溶性硒化镉(CdSe)量子点,利用组装技术和静电吸附作用,将带正电荷的血红蛋白(Hb)和带负电荷的CdSe量子点层层组装到壳聚糖(chit)修饰的玻碳电极(GCE)表面,构建基于{Hb/CdSe}n多层膜的无电子媒介体的电流型生物传感器({Hb/CdSe}3/chit/GCE).运用紫外-可见吸收光谱、电致化学发光、交流阻抗和循环伏安技术来表征修饰膜,并研究传感器的作用机理、性能及分析应用.结果表明:与量子点薄膜法及量子点/血红蛋白复合物法等固载血红蛋白的其他方法相比,层层组装法能显著提高血红蛋白的固定量,保持血红蛋白的生物活性,增强传感器的灵敏度和稳定性.传感器检测H2O2的线性范围为4.0×10-8～4.8×10-6 mol·L-1(r=0.999 1),检测限为2.0×10-8mol·L-l.多层膜的电致化学发光研究,表明修饰电极有望用于电致化学发光传感器的制备.     

硫醇分子链长对氧化还原自组装多层膜电化学行为影响的初步研究(英文)

以烷基硫醇和二茂铁衍生物构建的氧化-还原自组装多层膜为模型体系,研究烷基硫醇分子链长对多层膜电化学行为的影响.实验表明,二茂铁基团和电极之间的电子传递反应速率随两者距离的增加呈现指数级下降的趋势;烷基硫醇分子链长对自组装膜电化学行为的影响于不同情况下表现不同.本实验条件下,当多层膜上的电活性基团与电极比较接近时,长链分子自组装膜呈现较强的电化学响应.而当电极与电活性基团之间的距离较远时,短链烷基硫醇分子自组装膜呈现较强的电化学响应.     

树枝状大分子的自组装超薄膜

树枝状化合物因具有三维立体结构、均一的分布和多而密且可修饰性强的外官能团,使之作为结构单元进行自组装形成具有特色的超薄膜。Regen等利用整代聚酰胺－胺型（PAMAM）树状分子的胺端基,将其沉积到用Pt^2 离子活化的表面,重复这一过程即得到多层膜。Crook等首先报道了以共价键结合的树状分子膜,这种膜是将PAMAM树状分子的胺端基与巯基十一烷酸组成的单层膜作用生成酰胺键而形成的。Tsukruk等将表面分别带正负电荷的PAMAM树状分子在硅表面进行层状沉积形成超薄膜。研究显示,以树状分子为结构单元经自组装形成的膜具有潜在的用途前景,如作为化学探感器、多相催化剂、滤光片或光学器件基材等。     

二氧化钛超薄膜的组装

近年来LB膜技术和超微粒子研究的发展，将两者有效地结合起来组装了与量子电子学、非线性光学、光电化学、化学生物传感器有关的纳米量级无机半导体材料［‘－‘j．其中TIO。纳米薄膜材料已在太阳能电池反射膜、压电铁电薄膜、电致显示器件［‘j、可逆光电池和超导薄膜［’］研究中都显示了广阔的应用前景．这类薄膜制备多采用化学气相沉积（CVD）技术和原子层外延．也有人把LB技术应用于纳米粒子的组装来制备TIO。超薄膜［”’j二本文利用烷氧基钛在水／空气界面上发生的溶胶一凝胶化反应制备TIO。基胶态粒子及其固态凝聚膜，将其与…     

Polyelectrolyte/Gold Nanoparticle Nanotubes Incorporating Doxorubicin-Loaded Liposomes

Anticancer agent doxorubicin-loaded liposomes (DoxLs) were drawn spontaneously into nanotubes comprising multilayers of polyelectrolytes and gold nanoparticles (PAuNTs). We describe a unique structure of PAuNTs incorporating DoxLs (DoxL-PAuNT). The number of DoxLs adsorbed on the tube interior surface was ascertained as 2.4×10³. Heating stimuli engendered gel-liquid crystal phase transition of DoxL in the capillary, subsequently inducing efficient release of Dox without structural changes of the tubule or liposome. Furthermore, antitumor activity of the DoxL-PAuNTs on cancer cells was elucidated.     

基于聚集诱导发光金纳米簇构筑发光超薄膜

选用带负电的谷胱甘肽包裹的金纳米簇（GSH-AuNCs）和牛血清白蛋白包裹的金纳米簇（BSA-AuNCs）,与带正电荷的聚烯丙胺（PAH）通过静电作用以层层组装的方式制备了发黄色荧光的GSH-AuNCs/PAH薄膜和发红色荧光的BSA-AuNCs/PAH薄膜.在保证荧光强度的前提下,采用具有聚集诱导发光（AIE）效应的GSH-AuNCs能够大幅度降低薄膜厚度,有利于提高传感薄膜的响应速度和灵敏度.据此,以BSA-AuNCs/PAH薄膜作为参比层,GSH-AuNCs/PAH薄膜作为响应层,设计并构建了一种新型的比率荧光复合薄膜传感体系,并以2,4,6-三硝基甲苯（TNT）为例对其传感特性进行了研究.     

Characterization of Ultrathin Films of Cellulose Esters

The adsorption of cellulose acetate (CA), cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) from solutions prepared in acetone onto silicon wafers led to ultrathin films, which were characterized by ellipsometry, atomic force microscopy (AFM) and contact angle measurements. The polysaccharides films were characterized in the air just after their formation and after annealing at temperatures higher than their glass transition temperature or melt temperature. The films thickness close to 2 nm and surface roughness did not vary significantly upon annealing. AFM images revealed the presence of small clumps dispersed on a homogeneous layer, which covered completely the Si wafers. Such topographic details were also observed after annealing. However, upon annealing the films surfaces changed from hydrophilic to hydrophobic, evidencing molecular re-orientation at the solid–air interface. The adhesion of bovine serum albumin (BSA) and lipase onto the cellulose esters films was quantified in order to evaluate the possibility of applying such films as selective support for biomolecules.     

由聚电解质自组装多层膜制备微孔薄膜

带有相反电荷的聚电解质通过静电作用交替沉积可以得到自组装多层膜,由于这种技术可操作性强,用途广泛,近十几年来已有了大量的研究．聚电解质多层膜在一定条件下可以形成纳米孔和微米孔．Fu等研究了聚丙烯酸和聚乙烯基吡啶组成的氢键自组装多层膜在碱溶液中溶去其中的聚丙烯酸后,剩下的聚乙烯基吡啶重构形成微孔薄膜．Mendelsohn等发现将聚丙烯酸和聚烯丙基胺自组装而成的多层膜浸入pH=2．4左右的溶液中可制备微孔薄膜．但这些方法并不能使强聚电解质多层膜形成多孔结构。     

Electrochemical Production of Ultrathin Silicon Dioxide Films

Low-temperature synthesis of ultrathin (20 nm) SiO₂ films, by anodizing semiconductor single-crystal silicon wafers, is studied. Effects of physicochemical properties of electrolyte and single-crystal silicon on the films' dielectric characteristics are considered.     

Electrogenerated Chemiluminescence (ECL) Determination of Ephedrine with a Self-Assembly Multilayer Ni(II)-Polyluminol Modified Electrode

By combining the layer-by-layer (LBL) self-assembly technique with the electrochemical polymerization method, multilayer Ni(II)-polyluminol films were modified on the surface of a vaseline-impregnated graphite electrode. It was found that, compared with an electrode modified by direct electrochemical polymerization, this modified electrode offered a suitable ECL reaction micro-environment created by the special multilayer films, which was beneficial to the ephedrine hydrochloride enhancing effect for luminol ECL intensity. The ECL enhancing effect of ephedrine hydrochloride on the electro-oxidation luminol was improved on this modified electrode. Based on this finding, a new sensitive ECL method was developed for ephedrine hydrochloride determination under the optimal conditions. At the same time, a new idea is proposed for improving the analytical performance of the luminol ECL system by modifying the ECL reaction micro-environment with the layer-by-layer self- assembly method. Under the optimum experimental conditions, the ephedrine hydrochloride concentration in the range of 2.0 × 10⁻⁸–7.0 × 10⁻⁶ mol L⁻¹ was proportional to the enhanced ECL signal, and it offered an 8.0 × 10⁻⁹ mol L⁻¹ detection limit for ephedrine hydrochloride.