TiO2/十六烷基三甲基溴化铵有序交替层状纳米复合薄膜的制备与结构表征

近年来有序交替的层状纳米结构薄膜的制备吸引了研究者们的极大关注. 目前, 这类薄膜的制备方法研究得最多的是LB技术[1～3]、基于化学吸附的自组装成膜技术[4,5]和交替沉积组装技术[6～8]. 但这几种方法都有明显的缺陷[9,10], 其中,通过LB技术制备有序交替层状纳米复合薄膜需要昂贵的仪器, 而且由于层间是分子相互作用, 膜的稳定性较差; 基于化学吸附的自组装成膜技术由于需要高反应活性的分子和特殊的基底表面, 并且由于化学反应的产率很难达到100%, 因此通过这种方法制备结构有序的多层膜并不容易; 利用交替沉积的方法制备出具有实用厚度的纳米多层膜需要耗费大量的时间. 最近, 出现了一种称为蒸发诱导的超分子自组装方法, 由这种方法制备的纳米多层膜具有成膜速度快和膜有序度高等优点, 此外还可以通过改变成膜物质浓度和拉膜速度来控制薄膜的厚度, 但与LB膜相比其厚度无法在分子水平上控制. 利用这种方法制备多层膜目前的文献报道仅限于线形SiO2与有机物的组装[10～13]. 本文利用这种方法制备了TiO2/十六烷基三甲基溴化铵纳米复合薄膜并对其结构进行了表征, 结果表明所制备的薄膜具有TiO2/十六烷基三甲基溴化铵有序交替的层状结构.     

酞菁铜阴阳离子分子沉积(MD)膜润湿性研究

酞菁及其衍生物等大环平面分子具有良好的化学稳定性和优异的光电性能 [1,2 ] ,利用酞菁进行模拟生物光合作用的研究 ,以期实现新的光电转换技术 ,近年来已引起人们的广泛重视[3～ 5] .分子沉积(MD)超薄膜[6～ 8] 是以阴阳离子间静电相互作用为成膜驱动力 ,通过相反离子体系的单层交替沉积制备的层状有序超薄膜 .分子沉积技术广泛应用在固体表面改性和生物传感技术等领域 ,沉积分子的物理化学性质是影响其应用的主要因素 .本文通过紫外 -可见光谱跟踪了酞菁铜阴阳离子 MD膜的均匀沉积 ,并根据酞菁 MD膜表面接触角的变化 ,探讨分子端基的…     

聚(对乙烯基苯酚)的合成及其与重氮树脂的氢键自组装研究

带相反电荷的聚电解质,交替沉积在基片,形成超薄有序膜,通常称为静电自组装,自1991年由Decher首次阐明以来,静电自组装技术引起了广泛重视,利用氢键相互作用的氢键自组装1997年才有报道,沈家骢、张希等从聚丙烯酸和聚乙烯基吡啶通过氢键组装了有序超薄膜。和乙烯基吡啶通过氢键组装超薄膜的制备。由于静电力和氢键均很弱,此类膜对极性溶剂不稳定,如在DMF中会离解而遭破坏,我们曾报道重氮树脂（DR）与酚醛树脂间通过氢键的自组装,本文报道聚（对乙烯基苯酚）（PVPh）的制备及春与重氮树脂（DR）间的氢键相经作用,并结合光照,制备了对极性溶剂稳定的超薄膜。     

相反电荷取代的卟啉和酞菁化合物分子沉积膜

利用分子沉积技术成功地制备了多种卟啉 /卟啉、酞菁 /酞菁、卟啉 /酞菁化合物的分子沉积膜 (MD膜 ) .运用紫外 可见吸收光谱跟踪了MD膜的交替沉积过程 ,说明这类MD膜具有很好的层状均匀成膜的特点 .并且用膜天平 (QCM)技术和偏振紫外 可见吸收光谱技术对膜的结构进行了表征 .结果表明 ,卟啉和酞菁大环在MD膜中具有一定的取向 ,卟啉大环与基片法线的平均取向为 38℃ ,而酞菁大环为32℃ .     

一种含有偶氮磺酸基与吡啶基的高分子氢键自组装及自组装超薄膜

静电自组装是指将带相反电荷的聚电解质，于水溶液中交替沉积在片基上，制备多层超薄膜的技术．由于它在水溶液进行，技术简单，无需专用设备，再加上静电力比范德华力强，因此静电自组装膜比传统的LB(Langmuir—Blodget)膜稳定，在近年来得到很大发展．现在自组装成膜驱动力已从最初的静电力扩展到氢键、电荷转移相互作用、疏水相互作用等；用于组装的组分也从聚电解质扩展到多官能团小分子、胶体粒子、无机纳米     

CdS纳米微粒在LB膜层隙聚集形态的AFM观察

用LB技术制备纳米微粒与超薄有机膜的复合膜是近年来值得注意的研究进展＊．利用该方法所制备出的材料既具有纳米粒子所特有的量子尺度效应，又具有LB股的分子层次有序、股厚可控以及易于组装等特点．它可用来制备结构可控的有机无机交替膜．而且，通过改变LB膜成膜材料和制备条件还可改变纳米粒子的光电特性．因此它在微电子学、光电子学、非线性光学及传感器等研究领域有着十分广阔的应用前景问．纳米微粒的聚集形态及LB膜在生成纳米微粒后的结构变化对材料的特性有着很大的影响．但采用一般的电镜技术或光谱分析手段均不能在实空间和…     

自组装超薄膜: 从纳米层状构筑到功能组装

总结了一种新型的超薄膜自组装技术－交替沉积组装技术的发展现状,着重对成膜推动力、生物分子的层状组装、无机／有机杂化结构、有机小分子化合物的层状组装、超薄膜化学修饰电极、层间化学反应及非平衡基底上的层状构筑等几个方面的问题进行了讨论。     

端羧基芳脂型超支化聚酯自组装性能的研究

利用聚电解质逐层浸渍 ( layer- by- layer dipping)法制备自组装膜是最近发展起来的进行表面改性的新方法[1～ 3] .一方面 ,从理论上来说 ,只要是带电荷的聚合物都可以利用该技术制备具有优异性能的自组装膜 ;另一方面 ,还可以通过调节溶液的 p H值和离子强度等控制阴阳离子的组装过程 ,从而控制自组装膜的内部结构和表面形态 ,为在纳米级范围内设计和控制聚合物聚集态内部结构提供了可能性 .近年来 ,具有高度支化结构的超支化分子由于具有独特的物理和化学性能而受到了广泛的关注 [4 ,5] ,但以聚电解质逐层浸渍法制备超支化分子自组装膜…     

反应离子刻蚀和自组装分子膜构建硅基底疏水与超疏水表面

采用反应离子刻蚀技术在Si(100)表面加工微米级圆柱阵列, 采用自组装技术分别制备了3种硅烷自组装分子膜. 结果表明, 采用反应离子刻蚀构建出的4种微米级圆柱阵列结构规整, 其直径为5 μm, 高度为10 μm, 间距为15~45 μm. 沉积自组装分子膜后, 试样表面的水接触角显著增大, 其中沉积1H,1H,2H,2H-全氟癸基三氯硅烷(FDTS)自组装分子膜接触角最大, 1H,1H,2H,2H-全氟辛烷基三氯硅烷(FOTS)次之, 三氯十八硅烷(OTS)最小. 测得的接触角大于150°时接近Cassie方程计算的接触角, 而小于150°时接近Wenzel方程计算的接触角. 改变圆柱阵列的间距和选择不同的自组装分子膜, 可以控制表面接触角的大小. 原子力显微镜(AFM)观测结果显示, 沉积自组装分子膜可以产生纳米级的团簇. 由微米级圆柱阵列和纳米级自组装分子膜构成的表面结构使Si试样表面接触角最大可达156.0°.     

蜂窝状有序膜功能化研究进展*

水滴模板法是近年来引人瞩目的一种制备有序微结构材料的方法,所制备的蜂窝状有序膜在微容器和微反应器、图案化模板、细胞培养支架、光学材料、超疏水表面、分离膜等领域具有十分重要的应用前景。本文对蜂窝状有序膜功能化研究的最新进展进行了系统总结,详细介绍和分析了原位多层次自组装、表面接枝、生物活性分子固定、交联、模板法成膜以及表面填充等蜂窝状有序膜的功能化方法。     

联苯胺盐酸盐和聚阴离子有机超薄膜的制备和表征

有机薄膜具有良好的机械和化学稳定性、组成和厚度可控等优点 ,近年来被广泛接受[1 ,2 ] 。用自组装形成的多层复合膜已在渗透膜、导电膜、生物传感器、表面修饰改性、抗静电涂层、非线形光学器件等领域获得了广泛的研究[3,4] 。本文制备了以聚对磺酸钠苯乙烯和联苯胺盐酸盐的分子沉积膜。1　实验部分1 1　试剂与仪器聚对磺酸钠苯乙烯 (ＰＳＳ ,ＭＷ =70 0 0 0 ) ,4,4′—二氨基联苯胺盐酸盐 ,3 氨基丙基三乙氧基硅烷 (ＡＰＳ) ,未进一步处理。ＨＰ845 3型紫外可见光谱分析仪 ,日本协和科学株式会社产ＣＡ -Ａ型接触角测量仪 ,Ｌ1 1 6-Ｅ型…     

Self-assembled polyelectrolyte multilayer membranes with highly improved pervaporation separation of ethanol/water mixtures

Ethanol/water pervaporation through ultrathin polyelectrolyte multilayer membranes is described. The membranes were prepared by the layer-by-layer technique, i.e. by alternating sequential adsorption of cationic and anionic polyelectrolytes on a porous support. The separation capability was optimized by variation of the chemical structure of the polyelectrolytes, by variation of pH and ionic strength of the polyelectrolyte solutions used for membrane preparation and by annealing of the polyelectrolyte membranes. It was found that the separation is mainly affected by the charge density of the polyelectrolytes which is controlled by the chemical structure and the degree of ionisation of the polar groups. Selectivity for water was highest, if polyelectrolytes of high charge density such as polyethyleneimine (PEI), polyvinylamine (PVA) and polyvinylsulfate (PVS) were used and if the pH of the polyelectrolyte solutions was equal to the mean of the pK_a values of the corresponding cationic and anionic polyelectrolyte. Best results were obtained for PVA/PVS and PEI/PVS membranes which are characterized in detail with regard to their separation behavior.     

pH-sensitive bipolar ion-permselective ultrathin films

pH-Sensitive bipolar ion-permselective films of polyelectrolyte multilayers were prepared by layer-by-layer (LbL) assembly and photo-cross-linking of benzophenone-modified poly(acrylic acid) (PAA-BP) and poly(allylamine hydrochloride) (PAH-BP). The multilayer structure and ionizable group composition was finely tuned by changing the pH of the dipping solution. This structure and composition was in turn "preserved" by photo-cross-linking, forming highly stable membrane films. Since PAA-BP and PAH-BP are weak polyelectrolytes, it is possible to control the number of unbound, un-ionized -COOH or -NH2 groups in the multilayer by changing the pH. Moreover, the pH of the deposited film also plays an important role in determining selective latter permselectivity. For example, PAA-BP/PAH-BP multilayers deposited from two pH conditions, pH = 3 (PAA-BP) and pH = 6 (PAH-BP), showed pH-switchable permselectivity for both cationic (pH = 10) and anionic (pH = 3) probe molecules in a single film. The system offers advantages in film stability and introducing reversible selective ion permeability over previous multilayer film and cross-linking methods.     

Interaction of the anionic surfactant SDS with a cellulose thin film and the role of electrolyte and poyelectrolyte. 2 Hydrophilic cellulose

The interaction of the anionic surfactant, sodium dodecylsulfate (SDS), with the hydrophilic surface of a thin cellulose film and the role of electrolyte (0.1 M NaCl) and the polyelectrolyte, poly(dimethyldiallyl ammonium chloride) [polydmdaac], have been studied by neutron reflectivity (NR). The thin cellulose films were prepared by Langmuir-Blodgett (LB) deposition of trimethylsilyl-cellulose (TMSC) on silicon, and the hydrophilic surface was produced by the cleaving of the terminal methyl groups of the TMSC by HCl vapor. Despite both the surfactant and cellulose surfaces being nominally anionic, SDS adsorption and swelling of the cellulose film occurred during adsorption. The results show that the nature of the adsorption and the extent of the penetration into the cellulose film can be controlled by the addition of electrolyte, NaCl, and cationic polyelectrolyte, polydmdaac.     

聚电解质微球多级自组装制备双重药物载体

将表面带正电荷的壳聚糖(CS)微球和表面带负电荷的聚(L-谷氨酸)-b-聚氧化丙烯-b-聚(L-谷氨酸)(GPG)胶束共混,制备了CS/GPG聚集体水溶液体系.通过改变CS/GPG的共混比例,研究了CS微球和GPG胶柬形成稳定CS/GPG聚集体水溶液体系的配比范围,并对其粒径分布和表面电位进行了表征.在此基础上,将CS...     

Ultrathin organic semiconductor films — Soft matter effect

The growth of organic semiconductor thin films has been a crucial issue in organic electronics, especially the growth at the early stages. The thin-film phase has been found to be a common phenomenon in many organic semiconductor thin films, which is closely related with the weak van der Waals interaction between organic molecules, the long-range interaction between organic molecules and the substrate, as well as the soft matter characteristics of ultrathin films. The growth behavior and soft matter characteristics of the thin-film phase have great effects on thin film morphology and structure, for example, the formation and coalescence of grain boundaries, which further influences the performance of organic electronic devices. The understanding of thin-film phase and its intrinsic quality is necessary for fabricating large-size, highly ordered, continuous and defect-free ultrathin films. This review will focus on the growth behavior of organic ultrathin films, i.e., the level of the first several molecular layers, and provide an overview of the soft matter characteristics.     

Cellulose nanocrystal submonolayers by spin coating

Dilute concentrations of cellulose nanocrystal solutions were spin coated onto different substrates to investigate the effect of the substrate on the nanocrystal submonolayers. Three substrates were probed: silica, titania, and amorphous cellulose. According to atomic force microscopy (AFM) images, anionic cellulose nanocrystals formed small aggregates on the anionic silica substrate, whereas a uniform two-dimensional distribution of nanocrystals was achieved on the cationic titania substrate. The uniform distribution of cellulose nanocrystal submonolayers on titania is an important factor when dimensional analysis of the nanocrystals is desired. Furthermore, the amount of nanocrystals deposited on titania was multifold in comparison to the amounts on silica, as revealed by AFM image analysis and X-ray photoelectron spectroscopy. Amorphous cellulose, the third substrate, resulted in a somewhat homogeneous distribution of the nanocrystal submonolayers, but the amounts were as low as those on the silica substrate. These differences in the cellulose nanocrystal deposition were attributed to electrostatic effects: anionic cellulose nanocrystals are adsorbed on cationic titania in addition to the normal spin coating deposition. The anionic silica surface, on the other hand, causes aggregation of the weakly anionic cellulose nanocrystals which are forced on the repulsive substrate by spin coating. The electrostatically driven adsorption also influences the film thickness of continuous ultrathin films of cellulose nanocrystals. The thicker films of charged nanocrystals on a substrate of opposite charge means that the film thickness is not independent of the substrate when spin coating cellulose nanocrystals in the ultrathin regime (<100 nm).     

Nanostructured ultrathin films of alternating sexithiophenes and electropolymerizable polycarbazole precursor layers investigated by electrochemical surface plasmon resonance (EC-SPR) spectroscopy

Nanostructured ultrathin films of linear and dendrimeric cationic sexithiophenes, 6TNL and 6TND, respectively, alternated with anionic polycarbazole precursor, poly(2-( N-carbazolyl) ethyl methacrylate- co-methacrylic acid) or PCEMMA32, were successfully fabricated using the layer-by-layer self-assembly deposition technique. The two electro-optically active oligomers exhibited distinct optical properties and aggregation behavior in solution and films as studied by UV-vis and fluorescence spectroscopy. The stepwise increase of the 6TNL/PCEMMA32 and 6TND/PCEMMA32 layers was confirmed by UV-vis spectroscopy and in situ surface plasmon resonance (SPR) spectroscopy. The intralayer electrochemical polymerization and cross-linking behavior of the carbazole functionalized PCEMMA32 layers were then investigated using cyclic voltammetry (CV) and electrochemical surface plasmon resonance (EC-SPR) spectroscopy. The increase in current with each cycle confirmed intralayer cross-linking followed by the doping-dedoping process within these films. The two types of films differed with respect to dielectric constant and thickness changes before and after electropolymerization, indicating the influence of the oligothiophene layers. This demonstrated for the first time the preparation of highly ordered organic semiconductors alternated with in situ electropolymerizable layers in ultrathin films.     

聚-4-偶氮磺酸基苯乙烯与四-(三甲氨基苯基)-卟啉的自组装膜及其光电转换性能

聚-4-重氮基苯乙烯(PDS)在碱性水溶液下通过与Na₂SO₃反应,制备了聚-4-偶氮磺酸基苯乙烯(PDSS).作为负离子聚电解质PDSS能与四-(三甲氨基苯基)-卟啉(TTMAP)通过离子相互作用进行层-层自组装.光照下该组装膜中的离子键转变为共价键,结果是组装膜对极性溶剂和盐水溶液变为非常稳定,从而能直接在KCl水溶液中测定其光电流.结果表明,该组装膜具有良好的光电转换性质.     

Layer-to-layer adsorption of oppositely charged polyelectrolytes: The effect of molecular mass: 2. Bilayer systems

The effect of molecular mass on the formation of a bilayer structure upon the layer-to-layer adsorption of a cationic polyelectrolyte (poly(dimethyldiallylammonium chloride), molecular mass M = 500000 and 100000-200000 Da) and an anionic polyelectrolyte sodium (poly(acrylate), M = 30000 and 2100 Da) on the surface of fused quartz is studied by the capillary electrokinetic method. The time required to reach constant adsorption values and the structure of bilayer systems depend on the ratio between molecular masses of the cationic and anionic polyelectrolytes. The deformability of the bilayer system significantly exceeds that of the first layer in the case when the second layer is formed from an anionic polyelectrolyte with a lower molecular mass, thus suggesting the loosening of the first adsorption layer of the cationic polyelectrolyte. The adsorption of the anionic polyelectrolyte with higher molecular mass insignificantly affects the density of the first layer. Variation in the deformability of the layer with time (its aging) depends on the ratio between molecular masses of the polyelectrolytes.