| In recent years, there has been considerable intrest in molecular self-assembly, especially the fabrication of functional ordered ultrathin films — monolayer and multiplayer films, together with the developments of the life sciences,materials science and the nanoparticle technique, mostly owing to its simplicity,versatility, and the establishment of high level of order on a molecular scale as a means of preparing modified surfaces. The high oraganization and homogeneity, together with its molecular dimension, make it very attractive for tailoring surfaces with desired properties. Thus the anticipant reaction can go on selectively and the design of the electrode function can realize in molecular level on the surface of electrode.At chapter two of this article, we perfect resolve this problem in fabrication of a covalently attached multiplayer film electrode containing Anionic Fe(III) tetrakis (p-sulfonatophenyl) porphyrin (FeTSPP). The fabrication principle is shown as following: electrochemical oxidation of 4-aminobenzoic acid (4-ABA) in organic solution to form a self –assembled monolayer film, which leads to covalent attachment of amine cation radicals onto the GCE surface. Afterwards, the modified substrate was dipped into aqueous solution of DAR to obtain a positively charged surface. The multiplayer FeTSPP anions can be obtained by alternating deposition of FeTSPP with DAR based on electrostatic interaction. Owing to the well know photoreaction of diazo-nium and sulfonate groups, the above-assembled films containing multiplayer of DAR/FeTSPP were irradiated by UV light. The bonding of neighbor layers is converted from electrostatic interaction into covalent bonding. The conversion strengthened the stability of the multiplayer films. The deposition process was followed by UV-Vis absorption spectra and the photoreaction of diazo-nium and sulfonate groups was confirmed by UV-Vis absorption spectra and IR spectroscopy. Then we researched the electrocatalysis of the modified electrode to toward sulfite in detail, and it's stability. The resulting confirmed that a new method to fabricate covalently attached multilayer of cobalt phthalocyanine had been developed by exploiting the ionic self-assembly technique and then by photoreaction of diazonium and sulfonate groups in the multiplayer assemblies. This technique is a simple but efficient method to prepare highly stable FeTSPP multiplayer films. The modified electrode which was fabricated by the technique has stable and electrocatalysis response toward sulfite. The modified electrode has a fast response, good stability and reproducibility.At the chapter three, based on the electrostatic interaction, the multiplayer CoTsPc/DAR films can be obtained by alternating deposition of DAR and CoTsPc on the surface of a glassy carbon electrode modified with 4-ABA. Then the modified electrode was irradiated by UV light to convert the electrostatic interaction into covalent bonding. The technique ensured that every layer was connected with covalent bonding. This technique is a simple but efficient method to prepare a highly stable CoTsPc multilayer film electrode. The modified electrode that was fabricated by the technique has a stable and excellent electrocatalytic response toward the oxidation of hydrazine. In chronoamperometric studies, the diffusion coefficient of hydrazine for the modified electrode was calculated to be 6.2×10-7 cm2 s-1 for hydrazine.At the chapter four, we described the preparation of covalently attached multilayer thin films obtained via water-soluble binuclear cobalt phthalocyaninesulfonate (Bi-CoPc) and diazo-resins (DAR). The films were fabricated by sequential deposition of Bi-CoPc and DAR on quartz, CaF2 and glassy carbon electrodes (GCEs). Under UV irradiation, the linkage between layers of the films has been altered from ionic to covalent. The resulting films were then thoroughly characterized by UV-vis, FTIR, X-ray diffraction (XRD), atomic force microscope (AFM), surface photovoltage spectra (SPS), and cyclic volta...
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