Effect of core-shell micelle formation on the redox properties of phenothiazine-labeled poly(ethyl glycidy ether)-block-poly(ethylene oxide)

Ryohei Tsuda, Sayaka Kaino, Hisashi Kokubo, Shinichiro Imabayashi, Masayoshi Watanabe

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Redox properties of phenothiazine-labeled poly(ethyl glycidy ether)-block-poly(ethylene oxide) (PT-EGEn-b-EOm) are reversibly changed by core-shell micelle formation. In the temperature range higher than the critical micellization temperature (cmt), the anodic potential of PT group positively shifts and concomitantly its anodic current decrease, or levels off compared to those of the reference polymer PT-EOm without the thermo-responsive EGEn segment. The former alteration is caused by incorporation of hydrophobic PT groups into a core of the micelle and the latter by the decrease in the diffusion coefficient of PT groups due to formation of the core-shell micelles. The cmt value and the temperature-dependent alteration in the redox properties strongly depend on the polymer structure, especially the length of thermo-responsive EGEn segment. The electrochemically determined hydrodynamic radii of the polymer aggregates seem to be overestimated, compared to the values reported for the aggregates of other thermo-responsive polymers with similar molecular weights, implying the presence of electrochemically inactive PT groups in the copolymers having longer thermo-responsive segments.

Original languageEnglish
Pages (from-to)255-259
Number of pages5
JournalColloids and Surfaces B: Biointerfaces
Volume56
Issue number1-2
DOIs
Publication statusPublished - 2007 Apr 15
Externally publishedYes

Fingerprint

phenothiazines
Micelles
ethylene oxide
Polyethylene oxides
Ether
Ethers
ethers
micelles
Polymers
Micellization
polymers
critical temperature
Temperature
molecular weight
copolymers
Hydrodynamics
Copolymers
diffusion coefficient
Molecular weight
hydrodynamics

Keywords

  • Critical micellization temperature
  • Hydrodynamic radius
  • Phenothiazine
  • Temperature dependence of redox response
  • Thermo-responsive block copolymer

ASJC Scopus subject areas

  • Biotechnology
  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry
  • Surfaces and Interfaces

Cite this

Effect of core-shell micelle formation on the redox properties of phenothiazine-labeled poly(ethyl glycidy ether)-block-poly(ethylene oxide). / Tsuda, Ryohei; Kaino, Sayaka; Kokubo, Hisashi; Imabayashi, Shinichiro; Watanabe, Masayoshi.

In: Colloids and Surfaces B: Biointerfaces, Vol. 56, No. 1-2, 15.04.2007, p. 255-259.

Research output: Contribution to journalArticle

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AB - Redox properties of phenothiazine-labeled poly(ethyl glycidy ether)-block-poly(ethylene oxide) (PT-EGEn-b-EOm) are reversibly changed by core-shell micelle formation. In the temperature range higher than the critical micellization temperature (cmt), the anodic potential of PT group positively shifts and concomitantly its anodic current decrease, or levels off compared to those of the reference polymer PT-EOm without the thermo-responsive EGEn segment. The former alteration is caused by incorporation of hydrophobic PT groups into a core of the micelle and the latter by the decrease in the diffusion coefficient of PT groups due to formation of the core-shell micelles. The cmt value and the temperature-dependent alteration in the redox properties strongly depend on the polymer structure, especially the length of thermo-responsive EGEn segment. The electrochemically determined hydrodynamic radii of the polymer aggregates seem to be overestimated, compared to the values reported for the aggregates of other thermo-responsive polymers with similar molecular weights, implying the presence of electrochemically inactive PT groups in the copolymers having longer thermo-responsive segments.

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