Ultrathinning-Induced Surface Phase Separation of Polystyrene/Poly(vinyl methyl ether) Blend Film

Keiji Tanaka, Jeong Sik Yoon, Atsushi Takahara, Tisato Kajiyama, Jeong Sik Yoon

研究成果: ジャーナルへの寄稿記事

150 引用 (Scopus)

抄録

Polystyrene/poly(vinyl methyl ether) (PS/PVME) blend films were prepared on hydrophilic SiO substrates by a dip-coating method from toluene solution. The phase-separation temperature of the (PS/PVME) blend films decreased with decreasing film thickness. The (PS/PVME) two-dimensional ultrathin film with a thickness comparable to the dimension of twice the radius of gyration of an unperturbed PVME chain did not show any distinct cloud point. Secondary ion mass spectroscopic (SIMS) measurement for the perdeuterated polystyrene/FVME (dPS/PVME) thin film revealed the selective adsorption of the dPS segments on the hydrophilic substrate in order to minimize the polymer-substrate interfacial free energy. X-ray photoelectron spectroscopic (XPS) measurement showed the enrichment of PVME at the air-polymer interface due to its lower magnitude of surface free energy compared with that of PS. However, the PVME weight fraction at the air-facing surface started to decrease with decreasing film thickness for thickness less than ca. 30 nm. Atomic force microscopic (AFM) observation revealed that the (PS/PVME) two-dimensional ultrathin film with a thickness of 25 nm was in an apparent phase-separated state forming droplet-like domains 200-500 nm in diameter and 20-40 nm in height. Scanning viscoelasticity microscopic (SVM) observation revealed that the droplet-like domains were composed of a PVME-rich phase. These results clearly indicated that the spinodal point decreased below room temperature with decreasing film thickness for thickness less than ca. 30 nm. The formation of the phase-separated domains can be explained by factors such as the negative spreading coefficient of PVME on the PS matrix and the large negative conformational entropy of a PVME chain against stretching.

元の言語英語
ページ(範囲)934-938
ページ数5
ジャーナルMacromolecules
28
発行部数4
DOI
出版物ステータス出版済み - 7 1 1995

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Polystyrenes
Phase separation
Ethers
Film thickness
Ultrathin films
Free energy
Polymers
Substrates
Facings
Viscoelasticity
Toluene
Photoelectrons
Air
Stretching
Entropy
poly(vinyl methyl ether)
Ions
Scanning
Adsorption
X rays

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

これを引用

Ultrathinning-Induced Surface Phase Separation of Polystyrene/Poly(vinyl methyl ether) Blend Film. / Tanaka, Keiji; Yoon, Jeong Sik; Takahara, Atsushi; Kajiyama, Tisato; Yoon, Jeong Sik.

:: Macromolecules, 巻 28, 番号 4, 01.07.1995, p. 934-938.

研究成果: ジャーナルへの寄稿記事

Tanaka, Keiji ; Yoon, Jeong Sik ; Takahara, Atsushi ; Kajiyama, Tisato ; Yoon, Jeong Sik. / Ultrathinning-Induced Surface Phase Separation of Polystyrene/Poly(vinyl methyl ether) Blend Film. :: Macromolecules. 1995 ; 巻 28, 番号 4. pp. 934-938.
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abstract = "Polystyrene/poly(vinyl methyl ether) (PS/PVME) blend films were prepared on hydrophilic SiO substrates by a dip-coating method from toluene solution. The phase-separation temperature of the (PS/PVME) blend films decreased with decreasing film thickness. The (PS/PVME) two-dimensional ultrathin film with a thickness comparable to the dimension of twice the radius of gyration of an unperturbed PVME chain did not show any distinct cloud point. Secondary ion mass spectroscopic (SIMS) measurement for the perdeuterated polystyrene/FVME (dPS/PVME) thin film revealed the selective adsorption of the dPS segments on the hydrophilic substrate in order to minimize the polymer-substrate interfacial free energy. X-ray photoelectron spectroscopic (XPS) measurement showed the enrichment of PVME at the air-polymer interface due to its lower magnitude of surface free energy compared with that of PS. However, the PVME weight fraction at the air-facing surface started to decrease with decreasing film thickness for thickness less than ca. 30 nm. Atomic force microscopic (AFM) observation revealed that the (PS/PVME) two-dimensional ultrathin film with a thickness of 25 nm was in an apparent phase-separated state forming droplet-like domains 200-500 nm in diameter and 20-40 nm in height. Scanning viscoelasticity microscopic (SVM) observation revealed that the droplet-like domains were composed of a PVME-rich phase. These results clearly indicated that the spinodal point decreased below room temperature with decreasing film thickness for thickness less than ca. 30 nm. The formation of the phase-separated domains can be explained by factors such as the negative spreading coefficient of PVME on the PS matrix and the large negative conformational entropy of a PVME chain against stretching.",
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AB - Polystyrene/poly(vinyl methyl ether) (PS/PVME) blend films were prepared on hydrophilic SiO substrates by a dip-coating method from toluene solution. The phase-separation temperature of the (PS/PVME) blend films decreased with decreasing film thickness. The (PS/PVME) two-dimensional ultrathin film with a thickness comparable to the dimension of twice the radius of gyration of an unperturbed PVME chain did not show any distinct cloud point. Secondary ion mass spectroscopic (SIMS) measurement for the perdeuterated polystyrene/FVME (dPS/PVME) thin film revealed the selective adsorption of the dPS segments on the hydrophilic substrate in order to minimize the polymer-substrate interfacial free energy. X-ray photoelectron spectroscopic (XPS) measurement showed the enrichment of PVME at the air-polymer interface due to its lower magnitude of surface free energy compared with that of PS. However, the PVME weight fraction at the air-facing surface started to decrease with decreasing film thickness for thickness less than ca. 30 nm. Atomic force microscopic (AFM) observation revealed that the (PS/PVME) two-dimensional ultrathin film with a thickness of 25 nm was in an apparent phase-separated state forming droplet-like domains 200-500 nm in diameter and 20-40 nm in height. Scanning viscoelasticity microscopic (SVM) observation revealed that the droplet-like domains were composed of a PVME-rich phase. These results clearly indicated that the spinodal point decreased below room temperature with decreasing film thickness for thickness less than ca. 30 nm. The formation of the phase-separated domains can be explained by factors such as the negative spreading coefficient of PVME on the PS matrix and the large negative conformational entropy of a PVME chain against stretching.

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