Monomolecular Langmuir-Blodgett films at electrodes. Formation of passivating monolayers and incorporation of electroactive reagents
Monomolecular Langmuir-Blodgett films at electrodes. Formation of passivating monolayers and incorporation of electroactive reagents
复制标题
电极上的单分子 Langmuir-Blodgett 薄膜。
作者：
R. Bilewicz;M. Majda
将混合十八烷硫醇(Ci8SH)-十八烷醇（CigOH）单层膜通过Langmuir-Blodgett （LB）转移到玻璃载玻片上的气相沉积金膜上，当混合单层膜的组成中含有60-80 mol%十八烷硫醇时，可以形成稳定、致密的单分子膜。混合LB膜的这种组成是CigOH的摩尔分数和CigSH的摩尔分数之间权衡的结果，CigOH的摩尔分数增加了LB转移过程中混合单层的表面压力，而CigSH的摩尔分数增加了LB转移后混合单层在金表面的稳定性。用电化学方法研究了CigSH/CigOH LB单层膜的钝化性能。通过循环伏安法测定界面电容和测量表面单层的渗透程度表明，CigSH/CigOH LB单层的钝化特性基本上与文献中描述的最佳自组装十八烷硫醇单层相同。含有少量电活性试剂的单层的LB转移可以用作电极表面固定试剂的一般技术。与自组装方法不同，试剂掺入Langmuir-Blodgett单层可以在广泛的浓度范围内精确控制其组成。在LB转移前和LB转移后，CigSH/CigOH单层膜在空气/水界面处的泛醌表面浓度与电极表面的泛醌浓度在1.0 × 10~ 12-1.0 × 10~ 10 mol/cm* 12范围内呈1:1的相关性。
Langmuir-Blodgett (LB) transfer of mixed octadecanethiol (Ci8SH)-octadecanol (CigOH) monlayers onto vapor-deposited gold films on glass slides leads to the formationof stable, densely packed mono-molecular films when the composition of the mixed monolayers involves 60-80 mol% octadecanethiol. This composition of the mixed LB films is a result of a trade-off between the mole fraction of CigOH, whose increasing magnitude allows one to increase surface pressure of a mixed monolayer during an LB transfer, and the mole fraction of CigSH, whose increasingmagnitude enhances stability of themixed monolayer on the gold surface following the LB transfer. The passivating properties of CigSH/CigOH LB monolayers were investigated electrochemically. Determinationof interfacial capacitance and measurements of the extent of permeability of the surface monolayers by cyclic voltammetry demonstrated that the passivating characteristics of the CigSH/CigOH LB monlayers are essentially identical to the best self-assembled octadecanethiol monolayers described in the literature. LB transfer of monolayers containing small quantities of an electroactive reagent can be used as a general technique of reagent immobilization at the electrode surface. Unlike self-assembly methods, reagent incorporation in Langmuir-Blodgett monolayers offers precise control of their composition in a broad range of concentrations. Comparison of the surface concentrations of ubiquinone incorporated in CigSH/CigOH monolayers at the air/water interface before LB transfer and at the electrode surface following LB transfer gave 1: 1 correlations in the concentration range 1.0 X 10~ 12-1.0 X 10~ 10 mol/cm* 12.