| Project/Area Number |
01470106
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
高分子物性
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| Research Institution | Kyoto University |
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Principal Investigator |
TSUNASHIMA Yoshisuke Kyoto Univ., Inst. Chem. Res., Research Associate, 化学研究所, 助手 (30089130)
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| Co-Investigator(Kenkyū-buntansha) |
ODANI Hisashi Kyoto Univ., Inst. Chem. Res., Professor, 化学研究所, 教授 (70027019)
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| Project Period (FY) |
1989 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥4,700,000 (Direct Cost: ¥4,700,000)
Fiscal Year 1990: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1989: ¥3,900,000 (Direct Cost: ¥3,900,000)
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| Keywords | Dynamic Light Scattering / Polymer Diffusion / Hydrodynamic Interaction / Steady Shear Flow / Oseen Tensor / Navier-Stokes Equation / Polymer Solution / 非定常流 |
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| Research Abstract |
Flexible polymer chains in dilute solution show the diffusion motion due to thermal fluctuation of the chain segments. Dynamic light scattering spectroscopy has given direct information on the trans-lational diffusion coefficient and the internal relaxation times of the chains. However, the experimental results has not fully been explained from the theoretical and molecular point of view. The main reason might be due to Oseen approximation which has been customarily used to describe the hydrodynamic interaction exerted on the chain segments. It is well known that when the incompressible fluid is set in an one-dimensional flow, e. g., Couette flow, the Navier-Stokes equation describes exactly the hydrodynamics of the fluid and its exact solution gives the diffusion coefficient of suspended particles in the fluid without any approximation to the hydrodynamic interaction. In this work, We put the polymer chain into such an one-dimensional Couette flow and study the polymer chain dynamics through the dynamic light scattering technique. We poured dilute solutions of polystyrene (Mw=7.76x10^5) and poly (alphaーmethylstyrene) (Mw=2.7x10^6) in benzene (good solvent for both polymers) into the gap between an inner rotating and an outer rest cylinders of a coaxial rotating cylinder viscometer. An eddy-current drive of the inner cylinder yielded a very low shear flow intohe range of 0.57 - 5.3 sec^<-1>. The time correlation function of the scattered light from the solution was measured by a time-interval correlator and was then analyzed to estimate the translaーtional diffusion coefficient and the internal motions of the polymer chains in the Couette flow. Tt is found that the chain dynamics revealed shear-rate dependent behavior, but that at a small finite shear rate the internal motions disappeared and the translational diffusion coefficient could be detected without any ambiguity.
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