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Updated: Jan 21, 2026

Antifouling Self-assembled Monolayers on Microelectrodes for Patterning Biomolecules
Published on: August 25, 2009
Probing a Reversible Cationic Switch on a Mixed Self-Assembled Monolayer Using Scanning Electrochemical Microscopy
Ximing Huang1, Jingchao Chen1, Chunxia Yan1
1Beijing Key Laboratory of Photoelectronic and Electrophotonic Conversion Materials, Key Laboratory of Cluster Science (Ministry of Education), School of Chemistry and Chemical Engineering , Beijing Institute of Technology , Beijing 102488 , P. R. China.
Abstract:
Probing a switch on biomimic membrane surfaces would offer some references to the research on permeability of cytomembranes. In this work, a mixed 11-mercaptoundecanoic acid/1-undecanethiol self-assembled monolayer (MUA/UT SAM) was constructed as a model of a biomembrane. In this mixed SAM, the MUA molecules work as functional parts for the switch and the UT molecules work as diluents. The surface coverage, wetting property, and pKa of this mixed SAM all have been well-inspected. The mixed SAM exhibits excellent switchable properties for cations, which is well-monitored by scanning electrochemical microscopy. When the pH of a solution is higher than the pKa, protons would stimulate a shift of dissociation equilibrium of terminal carboxyl groups. The dissociated carboxylate ions would lead to a switch on the state of the SAM. Otherwise, the SAM shows an off state when the pH is lower than the pKa. In addition, the repeatability, applicability, and the mechanism of the switch all have been well-evaluated.
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