排序方式: 共有95条查询结果,搜索用时 15 毫秒
81.
采用扫描电化学显微镜测定了不同亲水性氧化还原电对在硫醇修饰的金电极表面上的异相电子转移速率常数. 分别选择铁氰化钾[K3Fe(CN)6]和N,N,N',N'-四甲基-1,4苯二胺(TMPD)作为氧化还原探针,根据得到的反馈曲线拟合出异相电子转移速率常数. 比较这些速率常数可以看出, 修饰层对疏水性的TMPD分子显示出更好的穿透性. 通过一个简单的模型可以解释TMPD的穿透过程, 在TMPD电子隧穿的前后存在着单层膜和水溶液间的快速平衡, 而隧穿作为决速步骤, 其表观速率常数也比K3Fe(CN)6的大. 通过计算得到TMPD的隧穿因子β为1.2/CH2. 相似文献
82.
研究了正十八烷醇在高定向热解石墨(HOPG)上形成自组装膜的吸附特性, 正十八烷醇在室温下从溶液中吸附至HOPG上形成整齐定向排列的单层自组装膜. 通过扫描隧道显微镜(STM)、接触角测量和X射线光电子能谱(XPS)分析了正十八烷醇单层自组装膜在HOPG上的结构. 实验结果表明, 正十八烷醇自组装膜在基底上成平铺或直立形态, 由于分子在基底上覆盖程度的不同, 会导致它在基底上排列的方式有所不同. 相似文献
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一种新的压电免疫传感器中生物分子固定化方法的研究 总被引:11,自引:0,他引:11
生物分子固定化或传感界面设计技术是研制压电免疫传感器的关键之一。本文 结合自组装单分子膜(SAMs)和聚电解质静电吸附组装技术,提出了一种新的压电 免疫传感器中生物分子固定化方法,研制成一种检测补体C_3的压电免疫传感器。 先在石英晶振的金电极表面组装一层胱胺SAMs,再在膜上组装带相反电荷的聚苯磺 酸钠(PSS)单层膜,通过静电吸附作用固定抗体(抗原),实现对相应抗原(抗 体)的检测。利用扫描电镜技术,从形态上考察了晶振组装胱氨SAMs与PSS及固定 补体C_3抗体后的表面形貌。研究了抗体的固定化条件,探讨了传感器采用这种固 定化方法的响应与再生性能,并与戊二醛键合固定法进行比较。结果表明,这种固 定化方法不仅对蛋白质类生物分子的固定化具有普适性,而且对所固定的生物分子 的活性影响小,传感器的响应的频移值大,灵敏度高,选择性和再生性能均较好。 相似文献
85.
Yang Bai Yan Zhang Wei Li Xuefeng Zhou Changsong Wang Xin Feng Luzheng Zhang Xiaohua Lu 《Applied Surface Science》2009,255(22):9296-9300
We report an effective approach to fabricate nanopatterns of alkylsilane self-assembly monolayers (SAMs) with desirable coverage and feature size by gradient photocatalysis in TiO2 aqueous suspension. Growth and photocatalytic degradation of octadecyltrichlorosilane (OTS) were combined to fabricate adjustable monolayered nanopatterns on mica sheet in this work. Systematic atomic force microscopy (AFM) analysis showed that OTS-SAMs that have similar area coverage with different feature sizes and similar feature size with different area coverages can be fabricated by this approach. Contact angle measurement was applied to confirm the gradually varied nanopatterns contributed to the gradient of UV light illumination. Since this approach is feasible for various organic SAMs and substrates, a versatile method was presented to prepare tunable nanopatterns with desirable area coverage and feature size in many applications, such as molecular and biomolecular recognition, sensor and electrode modification. 相似文献
86.
自组装膜吸附钯的化学镀前活化研究 总被引:9,自引:0,他引:9
提出了一种无需氯化亚锡敏化、基于分子自组装膜(SAMs)吸附钯的活化方法,成功地引发了在氧化铝粉末表面的化学镀铜.用XPS、AES、FTIR研究了钯的吸附机理,认为是由于氯化钯与SAMs上向外突出的氨基形成了化学键,并提出了相应的活化机理.金属化产物经XRD、FTIR、剖面金相显微表征分析与压片电阻率测定,示为金属铜完全包覆氧化铝的复合材料.该活化工艺具有活性引发层厚度薄、寿命长和与基底结合力强等优点,也可应用于其它表面富羟基的基底材料. 相似文献
87.
The analysis of wetting behavior of self-assembled monolayers of alkylsilanes is presented. A simple model accounting for various surface fractions of CH3 and CH2 groups (self-assembly order/disorder) is used. The effect of inclusion of air in the structure of rough silanized surfaces is also considered. The importance of reduced solid–water contact area and assembly order of organic monomers is demonstrated for achieving both high contact angle and low sliding angle. As coatings with low surface energy, these materials may be of potential use for ice-repellent purposes. 相似文献
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By using the established statistical thermodynamic theory of adsorbate-induced surface stress of adsorption monolayer on the metal surface, the surface stress Δgin the self-assembly of alkane thiolson Au (111) surface has been calculated. The quantitative relations of the surfaces tress Δgwith the length of the alkyl chain of the molecule and with the coverage θ of molecules on Au (111) have been theoretically Studied respectively. The calculated results agree with Bergeretalis experiment, and especially the quantitative discrepancy between the theory and experiment on the sign of the surface stress has been resolved.Among various components of the adsorbate-adsorbate interaction energies in the ad layer, the substrate mediated interaction is significant for the adsorbate-induced surface stress, which shows that the indirect contribution of the adsorption energy of alkane thiols through the substrate-mediated interaction is very important.This physical mechanism is similar to that for chloride monolayer on the Au (111) electrode. 相似文献
90.
Olivier Noel Maurice Brogly Gilles Castelein Jacques Schultz 《European Polymer Journal》2004,40(5):965-974
The atomic force microscope (AFM) was used to perform surface force measurements in contact mode to investigate surface properties of model systems at the nanoscale. Two types of model systems were considered. The first one was composed of a rigid substrate (silicon plates) which was chemically modified by molecular self-assembling (SAMs) to display different surface properties (hydroxyl, amine, methyl and ester functional groups). The second system consists of model polymer networks (cross-linked polydimethylsiloxane or PDMS) of variable mechanical properties, whose surfaces were chemically modified with the same groups as before with silicon substrates. The comparison of the force curves obtained from the two model systems shows that the viscoelastic or mechanical contribution dominates in the adhesion on polymer substrates. Finally, a relationship, which expresses the separation energy at a local scale as a function of the energy dissipated within the contact zone, on one hand and the surface properties of the polymer on the other, was proposed. 相似文献