TY - JOUR
T1 - Effect of core-shell micelle formation on the redox properties of phenothiazine-labeled poly(ethyl glycidy ether)-block-poly(ethylene oxide)
AU - Tsuda, Ryohei
AU - Kaino, Sayaka
AU - Kokubo, Hisashi
AU - Imabayashi, Shin Ichiro
AU - Watanabe, Masayoshi
N1 - Funding Information:
This work was partly supported by Grant-in-Aid for Scientific Research on Priority Areas of “Chemistry of Coordination Space” (No. 434/17036018, 18033015) and Grant-in-Aid for Scientific Research (C) (No. 17550125) from MEXT, Japan.
PY - 2007/4/15
Y1 - 2007/4/15
N2 - 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.
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.
KW - Critical micellization temperature
KW - Hydrodynamic radius
KW - Phenothiazine
KW - Temperature dependence of redox response
KW - Thermo-responsive block copolymer
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U2 - 10.1016/j.colsurfb.2006.11.018
DO - 10.1016/j.colsurfb.2006.11.018
M3 - Article
C2 - 17194577
AN - SCOPUS:33947542442
SN - 0927-7765
VL - 56
SP - 255
EP - 259
JO - Colloids and Surfaces B: Biointerfaces
JF - Colloids and Surfaces B: Biointerfaces
IS - 1-2
ER -