Project/Area Number  01470106 
Research Category 
GrantinAid for Scientific Research (B).

Research Field 
高分子物性

Research Institution  Kyoto University 
Principal Investigator 
TSUNASHIMA Yoshisuke Kyoto Univ., Inst. Chem. Res., Research Associate, 化学研究所, 助手 (30089130)

CoInvestigator(Kenkyūbuntansha) 
ODANI Hisashi Kyoto Univ., Inst. Chem. Res., Professor, 化学研究所, 教授 (70027019)

Project Fiscal Year 
1989 – 1990

Project Status 
Completed(Fiscal Year 1990)

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)

Keywords  Dynamic Light Scattering / Polymer Diffusion / Hydrodynamic Interaction / Steady Shear Flow / Oseen Tensor / NavierStokes Equation / Polymer Solution / 動的光散乱 / 高分子拡散 / 流体力学的相互作用 / 定常ずり流 / オゼン・テンソル / ナビア・ストクス方程式 / 高分子溶液 / 非定常流 
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 translational 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 onedimensional flow, e. g., Couette flow, the NavierStokes 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 onedimensional 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 eddycurrent 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 timeinterval 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 shearrate 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.
