Structure and morphology of self-assembled 3-mercaptopropyltrimethoxysilane layers on silicon oxide

Minghui Hu, Suguru Noda, Tatsuya Okubo, Yukio Yamaguchi, Hiroshi Komiyama

研究成果: Article

147 引用 (Scopus)

抄録

Self-assembled 3-mercaptopropyltrimethoxysilane (MPTMS, (CH3O)3SiCH2CH2CH2 SH) layers on hydroxyl-terminated silicon oxide (SiO2) were prepared at MPTMS concentrations ranging from 5 × 10-3 to 4 × 10-2M. The surface structure and morphology of MPTMS layers were characterized by X-ray photoelectron spectroscopy (XPS), contact angle measurements, scanning electron microscopy (SEM), and atomic force microscopy (AFM). We found that the MPTMS layers on SiO2 consisted of dispersed domains 20-200nm in diameter, instead of continuous, flat monolayers. With increasing MPTMS concentration, the domain shape changed from flat to steep. Flat domains were composed of well-ordered monolayers with thiol headgroups uniformly distributed on the uppermost surface, whereas steep domains were composed of disordered polymers with randomly distributed thiol headgroups on the uppermost surface. These results indicate that MPTMS molecules show good self-assembly at an MPTMS concentration of 5 × 10-3M, but not above this concentration. The effect of MPTMS concentration on the structure and morphology of MPTMS layers might be due to the competition between self-polymerization and surface dehydration reactions, which depends on the trace quantity of water in the solvent and on the SiO2 surface. Our research further indicates that MPTMS and water concentrations are the controlling parameters for preparing well-ordered, self-assembled MPTMS monolayers on SiO2.

元の言語English
ページ(範囲)307-316
ページ数10
ジャーナルApplied Surface Science
181
発行部数3-4
DOI
出版物ステータスPublished - 2001 9 21
外部発表Yes

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Silicon oxides
silicon oxides
Sulfhydryl Compounds
Monolayers
thiols
Water
Self assembled monolayers
Angle measurement
Dehydration
Surface structure
Hydroxyl Radical
Self assembly
Contact angle
Surface morphology
Atomic force microscopy
Polymers
X ray photoelectron spectroscopy
Polymerization
dehydration
water

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Condensed Matter Physics

これを引用

Structure and morphology of self-assembled 3-mercaptopropyltrimethoxysilane layers on silicon oxide. / Hu, Minghui; Noda, Suguru; Okubo, Tatsuya; Yamaguchi, Yukio; Komiyama, Hiroshi.

:: Applied Surface Science, 巻 181, 番号 3-4, 21.09.2001, p. 307-316.

研究成果: Article

Hu, Minghui ; Noda, Suguru ; Okubo, Tatsuya ; Yamaguchi, Yukio ; Komiyama, Hiroshi. / Structure and morphology of self-assembled 3-mercaptopropyltrimethoxysilane layers on silicon oxide. :: Applied Surface Science. 2001 ; 巻 181, 番号 3-4. pp. 307-316.
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AU - Komiyama, Hiroshi

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AB - Self-assembled 3-mercaptopropyltrimethoxysilane (MPTMS, (CH3O)3SiCH2CH2CH2 SH) layers on hydroxyl-terminated silicon oxide (SiO2) were prepared at MPTMS concentrations ranging from 5 × 10-3 to 4 × 10-2M. The surface structure and morphology of MPTMS layers were characterized by X-ray photoelectron spectroscopy (XPS), contact angle measurements, scanning electron microscopy (SEM), and atomic force microscopy (AFM). We found that the MPTMS layers on SiO2 consisted of dispersed domains 20-200nm in diameter, instead of continuous, flat monolayers. With increasing MPTMS concentration, the domain shape changed from flat to steep. Flat domains were composed of well-ordered monolayers with thiol headgroups uniformly distributed on the uppermost surface, whereas steep domains were composed of disordered polymers with randomly distributed thiol headgroups on the uppermost surface. These results indicate that MPTMS molecules show good self-assembly at an MPTMS concentration of 5 × 10-3M, but not above this concentration. The effect of MPTMS concentration on the structure and morphology of MPTMS layers might be due to the competition between self-polymerization and surface dehydration reactions, which depends on the trace quantity of water in the solvent and on the SiO2 surface. Our research further indicates that MPTMS and water concentrations are the controlling parameters for preparing well-ordered, self-assembled MPTMS monolayers on SiO2.

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