Blocking of an electrode reaction by a stearic acid monolayer
Blocking of an electrode reaction by a stearic acid monolayer
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硬脂酸单层阻断电极反应
DOI：
10.1016/0022-0728(89)85089-2
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发表时间：
1989
影响因子：
4.5
通讯作者：
K. Itaya
中科院分区：
文献类型：
--
作者：
I. Uchida;Atsushi Ishiho;T. Matsue;K. Itaya
LB膜由于可以在各种固体基底上构建分子有序性可控的LB膜而受到广泛关注。电化学方法最近已被应用于表征电极表面上的LB膜[1 -11]。形成LB膜的材料通常是由亲水基团和疏水链组成的两亲性化合物。这种疏水链可以为离子渗透[8]和电子隧穿1121提供高能量屏障，表明电极反应可能在固体电极上的完全转移单层处被完全抑制。先前的研究113，141表明，在汞电极上，氧化还原离子的渗透性在很大程度上取决于存在的单层的类型。然而，还没有使用固体电极进行类似的研究。固体表面应该是原子级平坦的，以达到一个完整的阻挡离子，因为它是合理的预期，在表面结构的不规则性会产生非理想的LB膜在固体substrates.In本文中，我们报告的电化学性能的硬脂酸LB单层附着到高度有序的热解石墨（HOPG）和火焰退火的Pt电极。最近使用扫描隧道显微镜（STM）的观察表明，两个电极的表面在原子尺度上都非常平坦[15，16]。循环伏安法和双电层电容测量表明，电极反应可以完全阻止LB单分子层在这些电极表面。
Langmuir-Blodgett(LB) membranes have been receiving a great deal of attention since ultrathin films, with control in the molecular order, can be constructed on various solid substrates. Electrochemical methods have recently been applied to the characterization of LB films on electrode surfaces [l-11]. Materials forming LB membranes are usually amphiphilic compounds, consisting of hydrophilic groups and hydrophobic chains. Such hydrophobic chains can provide a high energy barrier for ion penetration[8] and electron tunneling 1121, suggesting that electrode reactions might be totally inhibited at a perfectly transferred monolayer on solid electrodes. Previous studies 113,141 revealed that on mercury electrodes, the permeability of redox ions depends greatly on the types of monolayer present. However, no similar study has been carried out using solid electrodes. The solid surfaces should be atomically flat in order to attain a complete blocking of ions, since it is reasonable to expect that irregularities in surface structure would produce non-ideal LB films on solid substrates.In this paper, we report the electrochemical properties of a stearic acid LB monolayer attached onto highly ordered pyrolytic graphite (HOPG) and flame-annealed Pt electrodes. Recent observations using scanning tunneling microscopy (STM) showed that the surfaces of both electrodes are extremely flat on the atomic scale [15, 16]. Cyclic voltammetry and double layer capacitance measurements demonstrate that the electrode reaction can be completely blocked by an LB monolayer on these electrode surfaces.