In situ STM imaging of polyethylene glycol adsorbed on an Au(111) electrode in pH 3

Lai Han Li, Shuehlin Yau, Wei Ping Dow

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8 Scopus citations

Abstract

In situ scanning tunneling microscopy (STM) is used to examine the electrified interface of Au(111) immersed in a pH 3 sulfate medium containing polyethylene glycol (PEG) with an average molecular weight of 6000. The cyclic voltammograms thus obtained show two sharp peaks at − 0.35 and − 0.38 V (vs. reversible hydrogen electrode), which correlates with the STM observation of a highly ordered (2 × 2 √ 3)rect structure and the adsorption of PEGs. X-ray photoelectron spectroscopy is used to examine the film formed at − 0.4 V, revealing prominent C–C and C–O–C structures, thereby supporting the view of adsorption and reduction PEGs on the Au(111) electrode. STM imaging at the initial stage of PEG's adsorption reveals winding linear segments 0.6 nm wide and 20–40 nm long, implying helical conformations of PEGs. The PEG film dissolves and yields a high density of nanoclusters, as the potential is switched stepwise from − 0.4 to 0.9 V.

Original languageEnglish
Pages (from-to)1-4
Number of pages4
JournalElectrochemistry Communications
Volume70
DOIs
StatePublished - 1 Sep 2016

Keywords

  • Adsorption
  • Au(111)
  • In situ STM
  • Polyethylene glycol

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