Microstructures by Selective Desorption of Self-Assembled Monolayer from Polycrystalline Gold Electrodes

• Published in: Electroanalysis (New York, N.Y.) Vol. 19; no. 14; pp. 1467 - 1475
• Main Authors: Strutwolf, Jörg, O'Sullivan, Ciara K.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01-07-2007; WILEY‐VCH Verlag
• Subjects: EIS; Impedance; Microarray electrodes; Partially blocked electrodes; Polycrystalline gold; SAM; Selective desorption; Self-assembled monolayer
• ISSN: 1040-0397; 1521-4109
• DOI: 10.1002/elan.200703894

Potential‐controlled partial reductive desorption of a self‐assembled monolayer of mercaptopropionic acid (MPA) formed on polycrystalline gold electrodes is used to expose subdomains of bare gold to the electrolyte solution. Two sets of cathodic waves are observed in the reduction scan with MPA self‐assembled on a polycrystalline gold electrode. The origin of the two waves is ambiguous but there are indications that the waves are correlated with reductive desorption from the (111) and then simultaneously (100) and (110) index faces of a polycrystalline gold electrode. Consecutive reduction scans with reversing the potential direction after the first peak (but before the onset of the second wave) results in disappearance of the first wave. The exposed domains are then blocked by an assembling process of longer chain alkanethiols to create a mixed self‐assembled monolayer on polycrystalline gold electrodes. Desorption of the remaining MPA creates a partially blocked electrode and the blocking behavior towards hexacyanoferrate(III) is analyzed using the theory of partially blocked electrodes and indicates an array of interacting centers. The approach of partial reductive desorption may be exploited for use in biosensing applications where the exposed gold domains could be used for anchoring of DNA probes.