Surface structure of binary self-assembled monolayers formed by electrochemical selective replacement of adsorbed thiols

Daisuke Hobara, Takayuki Sasaki, Shinichiro Imabayashi, Takashi Kakiuchi

Research output: Contribution to journalArticle

96 Citations (Scopus)

Abstract

Nanometer-scale structure of binary thiol self-assembled monolayers (SAMs) prepared by the electrochemical selective replacement of adsorbed thiols in phase-separated binary SAMs has been studied by scanning tunneling microscopy (STM) and cyclic voltammetry. A phase-separated binary SAM of 1-undecanethiol (UDT) and 3-mercaptopropionic acid (MPA) is used as a starting system. MPA, which has a less negative desorption potential, is selectively removed by controlling the electrode potential, and replaced with 1-hexadecanethiol (HDT) or 11-mercaptoundecanoic acid (MUA). STM images of the UDT layer remaining after the selective removal of MPA exhibit two types of domains: domains with striped structure and domains where thiol molecules are densely packed, suggesting that some UDT molecules are reoriented and form low-density regions where the molecules are aligned flat on the surface. STM images of UDT-HDT and UDT-MUA binary SAMs formed by the replacement show surfaces which are phase-separated in nanometer scale. The size of the domains after the replacement is approximately equal to that of the initial phase-separated UDT-MPA SAM, indicating that the domain size is not significantly affected by the replacement.

Original languageEnglish
Pages (from-to)5073-5078
Number of pages6
JournalLangmuir
Volume15
Issue number15
DOIs
Publication statusPublished - 1999 Jul 20
Externally publishedYes

Fingerprint

3-Mercaptopropionic Acid
Self assembled monolayers
Sulfhydryl Compounds
thiols
Surface structure
Scanning tunneling microscopy
acids
Acids
scanning tunneling microscopy
Molecules
molecules
Cyclic voltammetry
Desorption
desorption
Electrodes
electrodes

ASJC Scopus subject areas

  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry

Cite this

Surface structure of binary self-assembled monolayers formed by electrochemical selective replacement of adsorbed thiols. / Hobara, Daisuke; Sasaki, Takayuki; Imabayashi, Shinichiro; Kakiuchi, Takashi.

In: Langmuir, Vol. 15, No. 15, 20.07.1999, p. 5073-5078.

Research output: Contribution to journalArticle

Hobara, Daisuke ; Sasaki, Takayuki ; Imabayashi, Shinichiro ; Kakiuchi, Takashi. / Surface structure of binary self-assembled monolayers formed by electrochemical selective replacement of adsorbed thiols. In: Langmuir. 1999 ; Vol. 15, No. 15. pp. 5073-5078.
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