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51.
Optical waveguide spectroscopy was used under non-contact conditions to analyze the visible absorption spectrum of poly(ethylene oxide) (M w = 150) modified cytochrome c (PEO150-cyt.c) adsorbed on an indium tin oxide (ITO) glass electrode. The redox reactions of the adsorbed PEO150-cyt.c were dynamically measured in situ in PEO oligomers (M w = 200). It was confirmed that PEO modification of cyt.c is effective in maintaining the redox activity of the cyt.c after adsorption on the ITO glass electrode. The PEO150-cyt.c adsorbed on the electrode re-dissolved gradually in PEO oligomer. Against this, PEO1000-cyt.c having longer PEO chains (M w = 1000) was found to be adsorbed stably on the electrode. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
52.
H. Kaczmarek L. . Lindn J. F. Rabek 《Journal of polymer science. Part A, Polymer chemistry》1995,33(6):879-890
Poly(ethylene oxide) (poly(oxy-1,2-ethanediyl) is rapidly oxidized by hydroxyl (HO?) and hydroperoxyl (HO) radicals generated by photolysis of hydrogen peroxide (H2O2) or by the catalytic decomposition of H2O2 by metallic silver. This process is accompanied by a chain scission during which the molecular weight decreases and the polydispersity changes. As a result of this process, the crystalline structure of poly(ethylene oxide) disappears, and the polymer becomes completely amorphous. © 1995 John Wiley & Sons, Inc. 相似文献
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The redox reaction of poly(ethylene oxide) (PEO)-modified hemoglobin (PEO–Hb) was analyzed in PEO oligomers with cyclic voltammetry. The PEO–Hb was made soluble in PEO with molecular weight of 200 (PEO200) containing 0.5 M KCI. Quasi-reversible redox signals of PEO–Hb were obtained by using an indium tin oxide (ITO) glass working electrode. PEO–Hb, cast on the ITO electrode, also showed the redox response in PEO with molecular weight of 400 (PEO400). The peak current of PEO–Hb on the ITO electrode gradually increased during potential cycling. The effect of the scan rate on the quantity of electricity (Q) was analyzed after the peak current reached a constant value. The constant Q value was observed at the scan rate ranging from 30 to 500 mV/sec. The number of reactive PEO–Hb molecules was estimated from this constant Q-value. It was suggested that the electron transfer was carried out at the first layer of the PEO–Hb which was in direct contact with the ITO electrode. The quantity of electricity of PEO–Hb increased when the ITO electrode was first washed in an aqueous medium with ultrasonicator. This strongly suggested that the more effective surface area of the ITO electrode turned to be covered with PEO–Hb when the microporous region of the ITO particles was more hydrated. 相似文献
55.
含锂沸石Li-FER提高PEO复合聚合物电解质电导率 总被引:3,自引:0,他引:3
通过离子交换方法使锂部分取代了镁碱沸石(FER)孔道壁上羟基中的氢,制得含锂沸石Li-FER. 将这种沸石作为无机填料加入到PEO/LiClO4聚合物电解质中,可以使其室温电导率提高三个数量级以上. 电化学测量表明, 锂离子与PEO和含锂沸石中氧的相互作用提高了聚合物电解质中锂离子的迁移数. 另一方面, 采用XRD, DSC, PLM等方法研究了电解质的结晶状况.结果表明, Li-FER可以作为PEO链段结晶的成核剂,使PEO电解质的晶粒得到细化, 结晶度降低,为Li+的传输提供了更多的非晶区通道. 这是Li-FER的加入促使PEO聚合物电解质电导率提高的两个主要原因. 相似文献
56.
Conor J. Twomey Shaw H. Chen Thomas N. Blanton Ansgar Schmid Kenneth L. Marshall 《Journal of Polymer Science.Polymer Physics》1994,32(10):1687-1695
In view of the residual crystallinity in PEO found to limit the solubility of some Nd3+-compounds, amorphous PEO (aPEO) was synthesized for exploration as an alternative host. Complexation, solubility limit, morphology, and response to moisture absorption in the doped systems were investigated using FTIR, DSC, TGA, and WAXD techniques. Representing a perturbation to the structural regularity present in PEO, aPEO was found to present lower solubilities for dopants (Nd(act)3 and Nd(acac)3, both characterized by a weak Nd3+–ether oxygen interaction. On the other hand, no difference in solubility was observed for dopant Nd(NO3)3, characterized by a strong Nd3+–ether oxygen interaction. Laser interferometry was employed to assess film homogeneity of the Nd(NO3)3-doped systems across a 20-mm diameter, and the measured peak-to-valley distortion values were observed to be encouraging for practical applications. © 1994 John Wiley & Sons, Inc. 相似文献
57.
Thin films of ZnSe and PEO–chitosan blend polymer doped with NH4I and iodine crystals were prepared to form the two sides of a semiconductor electrolyte junction. ZnSe was electrodeposited
on indium tin oxide (ITO) conducting glass. The polymer is a blend of 50 wt% chitosan and 50 wt% polyethylene oxide. The polymer
blend was complexed with ammonium iodide (NH4I), and some iodine crystals were added to the polymer–NH4I solution to provide the I−/I3−redox couple. The room temperature ionic conductivity of the polymer electrolyte is 4.32 × 10−6 S/cm. The polymer film was sandwiched between the ZnSe semiconductor and an ITO glass to form a ZnSe/polymer electrolyte/ITO
photovoltaic cell. The open circuit voltage (V
oc) of the fabricated cells ranges between 200 to 400 mV and the short circuit current between 7 to 10 μA. 相似文献
58.
Avinash Dundigalla Sheng Lin‐Gibson Vincent Ferreiro Matthew M. Malwitz Gudrun Schmidt 《Macromolecular rapid communications》2005,26(3):143-149
Summary: The unusual structure of poly(ethylene oxide) (PEO) and Laponite clay in transparent nanocomposite films was investigated using scanning electron, atomic force, and optical microscopy, and X‐ray scattering. Each method is sensitive to different aspects of structural features and together they measure the resulting morphology and shear‐induced orientation. On nanometer length scales, clay platelets were found to orient in bundles while polymer crystallinity was suppressed. Microscopy led to the observation of unexpected and highly oriented multilayers on the micron length scale.
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