Nano-Properties of Organized Monolayers and Their Control

surface acid/base properties of self-assembled thiol monolayers (SAMs) on gold has之前conducted using the surface mass titration method我们已经开发了这个项目。surface mass titratiohin which the mass change of the electrode surface due to ion association is measured duringtitration of SAMs using a quartz crystal microbalancehas the capability of evaluating both the surface pKa and acid density of SAMs simultaneously. Wehave examined effects of chain length电子solutions and surface acid density in single component and mixed SAMs on the surface pKaCOOH- and NH2-terminated SAMs. It is demonstrated by these results that the surface pKa isdependent on the structure of SAM or how acid/base centers are distributed. the main origin of thisdependence is concluded to be the lateral repulsive interaction between the surface charged species格式由acid/base equilibrium.我们通常发现surface pKa是有争议的由electrodepotentials:pKa shifted to negative direction when negative potentials were applied. the ion associationterminal COOH and cation in solution was examined in detail in order to clarify the originBased on mass measurements of desorbed COOH-terminated thiol，我们包含的solvated cation是与terminal carboxylate of SAM. thesolvation number is also determined for Li - D1+ Li - D1, K - Li - D1+ Li - D1 and Cs - Li - D1+ Li - D1。

The evaluation of surface acid/base properties of self-assembled thiol monolayers (SAMs) on gold has been conducted using the surface mass titration method we have developed in this project. The surface mass titratioh, in which the mass change of the electrode surface due to ion association is measured during the titration of SAMs using a quartz crystal microbalance, has the capability of evaluating both the surface pKa and acid density of SAMs simultaneously. We have examined effects of chain length, electrolyte solutions and surface acid density in single component and mixed SAMs on the surface pKa of COOH- and NH2-terminated SAMs. It is demonstrated by these results that the surface pKa is dependent on the structure of SAM or how acid/base centers are distributed. The main origin of this dependence is concluded to be the lateral repulsive interaction between the surface charged species formed by acid/base equilibrium. We also found that the surface pKa is controllable by the electrode potentials: the pKa shifted to negative direction when negative potentials were applied. The ion association between terminal COOH and cation in solution was examined in detail in order to clarify the origin of mass change during the titration. Based on mass measurements of desorbed COOH-terminated thiol, we conclude that the solvated cation is associated with the terminal carboxylate of SAM. The solvation number is also determined for LiィイD1+ィエD1, KィイD1+ィエD1 and CsィイD1+ィエD1.