Study on surface acid‐base property of carboxylic acid‐terminated self‐assembled monolayers by cyclic voltammetry and electrochemical impedance spectroscopy

Abstract

Abstract Cyclic voltammetry and electrochemical impedance spectroscopy were used to study the surface acid‐base property of carboxylic acid‐terminated self‐assembled monolayers (SAMs). A carboxylic acid‐terminated thiol, such as thioctic acid (l,2‐dithiolane‐3‐pentanoic acid), was self‐assembled on gold electrodes. Electron transfer between the bulk solution and the SAM modified electrode was studied at different pH using Fe(CN) 6 3− as a probe. The surface p K a . of thioctic acid was determined by cyclic voltammetry and electrochemical impedance spectroscopy to be 5.6 ± 0.1 and 5.8 ± 0.1, respectively. The method is compared with other methods of monolayer p K a measurement.