混合自组装膜的电化学行为研究

Electrochemical behaviors of hybrid self-assembled monolayers modified electrode

采用循环伏安法和交流阻抗法对由十八烷基硫醇和半胱胺在金电极上形成的混合自组装膜进行表征.结果表明,致密单层膜的形成有效阻碍了Fe(CN)63-探针分子的通过;参考点腐蚀模型,对两组分单层膜的交流阻抗谱进行计算机拟合,得到等效电路各元件的模拟值;最后通过改变溶液的pH(3.02～11.02),研究溶液中H+浓度对混合自组装单层膜在Fe(CN)63-溶液中电化学行为的影响.结果表明,在偏酸性条件下,电极响应较好.这一工作为研究异相电子传递和分子识别等提供了合适的模型.

The monolayered hybrid film composed of octadecanethiol and cysteamine was fabricated on gold electrode through a self-assembled method.The electrochemical characteristics of this film were studied by cyclic voltammetry（CV） and AC impedance techniques.It suggested that the movement of the Fe（CN）3-6 probe molecule would be effectively hindered by the compact film.Furthermore,the impedance spectroscopy can be interpreted in terms of an equivalent circuit based on the dot corrosion modle of a double-component monolayer.The parameters of the circuit elements representing electrochemical properties of the two parts were obtained by fitting.A series of pH values from 3.02 to 11.02 of the Fe（CN）3-6 solution were employed and the response was tested in the experiment,showing a better CV behavior of the film in acid conditions compared with the alkaline case.This work offfers an appropriate model for researches of heterogeneous electron transfer and molecular recognition.