Probing Qualitative Change in Intermolecular Forces from Hydrogen Bonding to Electrostatic Interaction on the Surface of Self-Assembled Monolayer

• Published in: Journal of the Electrochemical Society Vol. 165; no. 5; pp. H240 - H246
• Main Authors: Huang, Ximing, Zheng, Qing, Fang, Xiaotong, Shao, Huibo
• Format: Journal Article
• Language: English
• Published: The Electrochemical Society 01.01.2018
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/2.0731805jes

In this work, a 3-mercaptopropionic acid self-assembled monolayer (3-MPA SAM) was constructed as a reliable artificial membrane to investigate the intermolecular forces between the SAM and the redox species using scanning electrochemical microscopy. The results presented here reveal that the redox species, FcCH2OH, is initially adsorbed on 3-MPA SAM by hydrogen bonding between the hydroxyl group of the former and the carboxyl group of the latter. Then, when FcCH2OH is transformed to Fc+CH2OH by electrochemical oxidation, the dominant intermolecular force in the reaction system changes from hydrogen bonding to electrostatic interaction. Increase in pH and surface coverage of the 3-MPA SAM can enhance the change behavior observed, however, adding ion strength will weaken this behavior. Our findings may help to improve the understanding of the interaction between effector proteins and phospholipid bilayer on cellular surface.