用简便方法组装二维模板银纳米阵列

通过制备甲基和羧基混合自组装单层膜, 然后在羧基基团上选择性地生长银制备二维模板银纳米阵列. 利用微接触印刷在金膜上制备模板自组装单层膜, 也就是利用具有二维微米图案的弹力印模把有机巯基化合物转移到金膜上. 改善的银镜反应被用来制备银纳米结构, 银纳米粒子选择性地生长在二维模板有机单分子层的羧基位置. 甲醇作为还原剂具有高的选择性和原子经济性, 一分子甲醇可以还原六个银离子. 利用原子力显微镜和扫描电子显微镜确定了银纳米结构的形貌, 用拉曼光谱研究银纳米结构的光学性质.     

DNA分子在气液界面的组装相变特性及其LB膜结构研究

对十八胺与DNA在气液界面上组装及其相变过程进行了研究，利用AFM观察了不 同压力下转移的DNA复合LB膜结构。发现在低表面压时，DNA复合单分子膜表现为技 术发散的分形结构；随着压力的升高，DNA复合膜逐渐由紧密的网状排布结构变为 团聚的块状和团簇结构。表明通过调节膜压，可使膜内DNA分子的构象发生大的变 化，从而生成具有特定形态的二维纳米图案。这种具有特殊形态和结构的DNA LB膜 可望为合成新型生物纳米结构有序功能体系提供模板。     

纳米半导体硫化银单层膜的自组装

本文使用Triton X-100作为模板剂制备半导体硫化银纳米颗粒,并研究了其吸收光谱的兰移特性。在金属铝或金基底上自组装有机双功能分子单层膜后,将其浸入所制备的纳米硫化银颗粒的微乳液中,自组装得到硫化银纳米颗粒单层膜并研究了其表面形貌特征。     

利用侧链修饰寡聚DNA组装CdS有序纳米结构

由于 DNA分子具有特殊的结构和碱基配对特性 ,人们已经意识到利用 DNA分子将无机纳米粒子 (量子点 )组装成各种不同的有序纳米结构的可行性 [1～ 5] .如 Mirkin等 [6 ,7]利用端基修饰的寡聚 DNA将金纳米粒子组装成有序的六方堆积的层状结构 .Alivisatos等 [8]利用单链 DNA为模板 ,通过在 3′和5′端修饰巯基的互补 DNA将两个或三个金纳米粒子连接起来形成“人造分子”.本文中我们首次报道通过在侧链 ( 5′端 C1和 C2之间的磷酸根 )上修饰巯基的寡聚胞嘧啶 ( Oligo C10 - SH )和寡聚鸟嘌呤( Oligo G10 - SH)复性过程将 Cd S纳米…     

DNALB膜的AFM形貌观察

DNA分子本身所具有的独特性质使其在生物学、医学和遗传学等领域占有极其重要的位置 ,近年来 ,人们意识到利用 DNA作为模板剂建造具有特殊结构和功能的纳米材料的可行性 [1] ,如 Braun等 [2 ]将寡聚核苷酸连接在两个金电极之间 ,用 DNA分子作为模板剂生长出 1 2 μm长、直径 1 0 0 nm的银纳米线 ;Mirkin等 [3]将 3 和 5 端连有巯基的寡聚核苷酸与金纳米粒子结合 ,通过互补的碱基形成介观尺寸的组装体 ;Alivisatos等 [4]利用 DNA的特点 ,使其与之相连的金纳米粒子按预计的形式排布形成人造分子 .我们尝试利用 LB技术将 DNA分子复合到…     

Cds纳米微粒的聚四氟乙烯多孔膜法制备及其表面修饰

硫化镉;Cds纳米微粒的聚四氟乙烯多孔膜法制备及其表面修饰;纳米粒;多孔膜;表面修饰;聚四氟乙烯     

基于新型DNA金属化工艺银纳米线的备

随着DNA金属化工艺逐渐发展,以DNA为模板进行金属纳米线的制备,使得生物与微细加工技术的结合变得可能．我们将DNA模板金属化工艺加以改进,利用半导体材料——硅作为样品衬底,并在硅片上利用Parafilm疏水膜斜向拉伸排列DNA分子,采用化学还原反应,成功地进行了银纳米线的制备．改进后的金属化工艺对DNA分子金属化程度较好,而且制备出了金属纳米网状结构．基于DNA构筑复杂纳米图形的实现,进行相关的金属化,有望构筑纳米集成电路．     

基于新型DNA金属化工艺银纳米线的制备

随着DNA金属化工艺逐渐发展, 以DNA为模板进行金属纳米线的制备, 使得生物与微细加工技术的结合变得可能. 我们将DNA模板金属化工艺加以改进, 利用半导体材料——硅作为样品衬底, 并在硅片上利用Parafilm疏水膜斜向拉伸排列DNA分子, 采用化学还原反应, 成功地进行了银纳米线的制备. 改进后的金属化工艺对DNA分子金属化程度较好, 而且制备出了金属纳米网状结构. 基于DNA构筑复杂纳米图形的实现, 进行相关的金属化, 有望构筑纳米集成电路.     

基于硫化镉纳米团簇标记DNA电化学传感的研究

合成了表面具有自由羧基的硫化镉纳米团簇，以乙基-（3-二甲基丙基）碳二 亚胺盐酸盐为偶联活化剂，将其标记于人工合成的5'端氨基修饰的寡聚核苷酸片段 上，制备成CdS纳米团簇标记DNA探针，该寡聚核苷酸片段与大肠杆菌肠毒素基因相 关。在一定的条件下，使基与固定晨玻碳电极表面的待测DNA序列进行杂交反应， 利用阳极溶出示差脉冲伏安法（ASDPV）间接测定Cd的量，实现对互补、非互补 DNA片段的识别和电化学检测，从而对大肠杆菌肠毒素基因片段识别和检测。     

Au@Pt纳米粒子单层膜对甲醇氧化的电催化性能及SERS研究

通过种子生长法合成Au@Pt核壳结构纳米粒子,采用两相成膜法制备单层粒子膜,并转移获得Au@Pt核壳纳米粒子单层膜电极,该电极表面纳米粒子分布均匀,具有较大的比表面,对甲醇的氧化具有较好的电催化活性.研究表明,利用内核Au的长程电磁场增强效应,该单层膜表现出均匀且优良的表面增强拉曼散射(SERS)活性,适合作为基底在分子水平上研究表面的吸附和反应.获得了Au@Pt核壳纳米粒子单层膜表面甲醇电催化氧化过程的SERS光谱,为深入分析表面反应机理提供了实验依据.     

Temperature-assisted photochemical construction of CdS-based ordered porous films with photocatalytic activities on solution surfaces

Taking a colloidal monolayer floating on the surface of a precursor solution as template, free-standing CdS/Cd composites and pure CdS (CdS-based) ordered porous films had been prepared by a temperature-assisted photochemical strategy. After irradiation with UV-light and heat treatment, the films formed hemi-spherical pores due to the preferable deposition of CdS and Cd onto the PS spheres during the photochemical and interfacial reactions. When the temperature increased from 15 to 60°C, the air/water interface gradually changed into a vapor/water interface on the surface of the solution, resulting in variations of the final compositions. The optical properties of the films were hence changed. Because of the free-standing characteristic, the ordered porous films were first transferred on surface of polluted solutions as photocatalysts, which was a new mode in application of photocatalysts. The photocatalytic activities of films showed regular variations with the compositions in photodegradation of Rhodamine B. This method provides a simple route for tuning the properties of porous films through control of its composition and a flexible application of films on any surface.     

Preparation of nanosized ZnS-passivated CdS particle films via the MOCVD process with co-fed single source precursors

A novel approach was developed to prepare thin films of nanosized ZnS-passivated CdS particles via a metal-organic chemical vapor deposition (MOCVD) process with co-fed single source precursors of CdS and ZnS. Single source precursors of CdS and ZnS with sufficiently different reactivity, as judged from thermogravimetry analysis, were prepared and paired up to form ZnS-passivated CdS, (CdS)ZnS, and CdS-modified ZnS, (ZnS)CdS, particle films in a one-step process. For comparison purposes, sequential layer growth of CdS/ZnS and ZnS/CdS particle films was also conducted, and single compound particle films were prepared. These films were characterized with absorption spectrometry, photoluminescence spectroscopy, scanning electron microscopy, and powder X-ray diffraction spectra. The photoluminescence efficiency of the resulting composite particle film of ZnS-passivated CdS was significantly enhanced as compared to that of the plain CdS film, due to the effective passivation of surface electronic states of CdS by ZnS, a material with a higher conduction band than that of CdS. As for particle films of CdS-modified ZnS, a decay in photoluminescence efficiency was observed. The enhancement or decay in photoluminescence efficiency was much more pronounced for the passivated and modified system than for the sequential layer system, proportional to the interfacial area between the CdS and ZnS phases.     

Headgroup effects of template monolayers on the adsorption behavior and conformation of glucose oxidase adsorbed at air/liquid interfaces

Stearic acid (SA) and octadecylamine (ODA) monolayers at the air/liquid interface were used as template layers to adsorb glucose oxidase (GOx) from aqueous solution. The effect of the template monolayers on the adsorption behavior of GOx was studied in terms of the variation of surface pressure, the evolution of surface morphology observed by BAM and AFM, and the conformation of adsorbed GOx. The results show that the presence of a template monolayer can enhance the adsorption rate of GOx; furthermore, ODA has a higher ability, compared to SA, to adsorb GOx, which is attributed to the electrostatic attractive interaction between ODA and GOx. For adsorption performed on a bare surface or on an SA monolayer, the surface pressure approaches an equilibrium value (ca. 8 mN/m) after 2 to 3 h of adsorption and remains nearly constant in the following adsorption process. For the adsorption on an ODA monolayer, the surface pressure will increase further 1 to 2 h after approaching the first equilibrium pressure, which is termed the second adsorption stage. The measurement of circular dichroism (CD) spectroscopy indicates that the Langmuir-Blodgett films of adsorbed GOx transferred at the first equilibrium state (π = 8 mN/m) have mainly a β-sheet conformation, which is independent of the type of template monolayers. However, the ODA/GOx LB film transferred at the second adsorption stage has mainly an α-helix conformation. It is concluded that the specific interaction between ODA and GOx not only leads to a higher adsorption rate and adsorbed amount of GOx but also induces a conformation change in adsorbed GOx from β-sheet to α-helix. The present results indicate that is possible to control the conformation of adsorbed protein by selecting the appropriate template monolayer.     

电沉积法制备介孔TiO_2/CdS薄膜光电极

采用阴极恒电位沉积法,在介孔TiO2薄膜上制备了介孔TiO2/CdS薄膜光电极,用XRD,SEM,Raman,SPS和UV-Vis等多种手段对薄膜电极进行了表征.结果表明,CdS成功沉积到介孔TiO2的表面和孔道内,形成了异质结结构.通过光电流作用谱考察了该复合体薄膜电极的光电性能,结果表明,与单纯的介孔TiO2薄膜相比,其光电转换效率显著提高,这是由于CdS具有吸收可见光的特性以及CdS与介孔TiO2形成异质结从而使得光生载流子更容易分离的结果.     

Interfacial assembly of a phospholipid Langmuir monolayer by electrodeposited silver colloids

Two-dimensional nanostructured silver films were electrodeposited at the surface of a silver nitrate subphase coated by a negatively charged dimyristoylphosphatidylglycerol (DMPG) Langmuir monolayer. The modifications of the phospholipid interfacial organization generated by the growing colloidal silver film were investigated using surface pressure-time isotherms and grazing incidence X-ray diffraction experiments (GIXD). A decrease in the initial surface pressure of the DMPG monolayer is observed outside of the growing silver film, followed by a stabilization of the surface pressure when the radius of the metallic layer reaches its plateau value. This behavior is attributed to the compression of the DMPG molecules above the silver film and to the correlated relaxation and expansion of those outside the silver film area as recorded by a Wilhelmy pressure sensor. GIXD experiments further evidenced the contraction of the phospholipid monolayer above the electrochemically growing films. Indeed, the diffraction spectra show a shift in the peak position toward higher values of the in-plane component of the wave-vector transfer, indicating a closer packing of the DMPG alkyl chains. This is also in agreement with the observed loss of the chain tilt angle, suggesting that the colloidal silver film induces interfacial structuring of the DMPG monolayer.     

Light-Induced Charge Transfer at Interface Between Lipid-Free RhTSPc Film and p-Si(111)

The present paper covers the lipid-free rhodium tetrasulfonato-phthalocyanine (RhTSPc) films prepared on p-Si(111) by using Langmuir-Blodgett technique. Their surface photovoltage spectra were measured. It was found that there is a strong interaction at the interface between the RhTSPc film and p-Si (111) and that the surface photovoltaic effect of the film system is maximum when only one monolayer of RhTSPc molecules coats p-Si(111), which is similar to that of CuTSPc films on p-Si(111) reported previously. These results confirm that only the monolayer of dye molecules being adjacent to the semiconductor surface plays a key role in the light-induced interfacial charge transfer process.     

Autophobic dewetting of Z-tetraol perfluoropolyether lubricant films on the amorphous nitrogenated carbon surface

The thermodynamic stability of thin films of the perfluoropolyether (PFPE) Z-Tetraol, as a function of molecular weight, on amorphous nitrogenated carbon, CNx, is investigated. An optical surface analyzer is used to image the autophobic dewetting of the Z-Tetraol films. Film dewetting results when the PFPE film thickness applied to the CNx surface exceeds a critical value. This critical dewetting thickness is identified as the monolayer thickness of the adsorbed PFPE film via measurements of the changes in the surface energy as a function of lubricant film thickness. The observed dewetting coincides with the film thickness at which the disjoining pressure goes to zero. The critical dewetting thickness is dependent on the PFPE molecular weight.     

CdS Thin Films Deposited by CBD Method on Glass

CdS thin films were prepared by chemical-bath-deposited method and the effect of tempera-ture and time on the properties of CdS thin films was studied. Independent of the deposited temperature, the growth was mainly controlled by the ion-by-ion growth mechanism at the beginning of the film deposition, then the cluster-by-cluster mechanism came to be domi-nant. The growth rate increased faster with the increasing of temperature until the thickness reached the limitation, then thickness instead become thinner. The scanning electron micro-scope results revealed that the morphology of the CdS film changed from pinholes to rough,inhomogeneous surface with increasing deposition time and deposition temperature. The X-ray diffraction results showed the film structure was a mixture of two phases: hexagonal and cubic, and it was very important to controll deposition time to the film's crystal phase. All films in depth of approximate 100 nm existed above 65% transmittance, the absorption edge became 〝red-shift〞 with temperature rising. At 60 and 70 oC, with 20 min deposited-time, the energy band gap was more than 2.42 eV and decreased with time, while at 80 and 90 oC, the energy band gap was less than 2.42 eV and increased little when the time changed from 10 min to 15 min at 80 oC.     

Adsorption behavior of glucose oxidase on a dipalmitoylphosphatic acid monolayer and the characteristics of the mixed monolayer at air/liquid interfaces

A dipalmitoylphosphatic acid (DPPA) monolayer at the air/liquid interface is used as a binding layer to incorporate glucose oxidase (GOx) from the subphase. The effects of the adsorption time of GOx on the behavior of the mixed DPPA/GOx monolayer and the relevant structure of the mixed LB film were studied using the characteristics of the pressure-area (pi-A) isotherm, Brewster angle microscopy (BAM), and atomic force microscopy (AFM). The experimental results show that two equilibrium states of GOx adsorption exist in the presence of a DPPA monolayer. The first equilibrium stage occurs at tens of minutes after spreading of DPPA, and a surface pressure of ca. 7.5 mN/m is obtained. The second equilibrium stage approaches slowly, and a higher equilibrium surface pressure (ca. 16 mN/m) was obtained at ca. 8 h after the first stage. The BAM and AFM images show that, after the second equilibrium stage is reached, a more condensed phase and rough morphology are obtained on the mixed DPPA/GOx monolayer, indicating a higher amount of GOx incorporated into the mixed film. For the first equilibrium stage of GOx adsorption, DPPA molecules can still pack regularly and closely under compression, suggesting that GOx molecules are mainly located beneath the DPPA monolayer at the compressed state. A more uniform phase was detected on a film prepared after the first equilibrium stage was reached. The present result indicates that distinct structures and properties of mixed DPPA/GOx films can be prepared from the various stages of GOx adsorption.