1999 Fiscal Year Final Research Report Summary
Studies of the Conformation of Polyelectrolytes and Excluded-Volume Effects on Them
| Project/Area Number |
09450363
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
高分子構造・物性(含繊維)
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| Research Institution | Osaka University |
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Principal Investigator |
NORISUYE Takashi Graduate School of Science, Osaka University, Professor, 大学院・理学研究科, 教授 (10028227)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Polyelectrolyte / Conformation / Excluded-Volume Effect / Persistence Length / Electrostatic Interaction / Light Scattering / Radius of Gyration / Translational Diffusion Coefficient |
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| Research Abstract |
The present study was undertaken to elucidate the effects of electrostatic interactions on chain stiffness (or conformation) and excluded-volume effect in naturally occurring and synthetic polyelectrolytes. The radii of gyration, intrinsic viscosities, and translational diffusion coefficients of sodium hyaluronate (HA), succinoglycan (Na salt), Na poly (styrenesulfonate) (NaPSS), and Na poly (isoprenesulfonate) (NaPI) in aqueous NaCl determined by static and dynamic light scattering, small-angle X-ray scattering, and viscometry were analyzed by the current theories for unperturbed wormlike chains combined with the quasi-two-parameter theory for excluded-volume effects. The analysis substantiated that for intrinsically flexible or weakly stiff polymers (HA, NaPSS, and NAPI), electrostatic stiffening and volume effects are responsible for the observed increases in molecular size with lowering ionic strength. The molecular weight dependence of each property was found to be explained almost quantitatively by the above-mentioned theories for uncharged polymers if the ionic strength is not lower than 0.01-0.05M. On the other hand, the chain dimensions of succinoglycan were almost independent of ionic strength above 0.05M because of the high stiffness comparable to that of double-stranded DNA. The data analysis strongly suggested that the ordered structure of this polysaccharide (stable below 40。・ be double-helical.
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