| Autor: |
Takebe, Tomoaki, Nawa, Kazunari, Suehiro, Shoji, Hashimoto, Takeji |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 10/1/1989, Vol. 91 Issue 7, p4360, 9p |
| Abstrakt: |
Cooperative diffusion D of polyacrylamide gels in water was investigated by quasielastic light scattering both under the isotropically swollen state and under the uniaxially stretched and swollen state. The concentration (Ce) dependence of D for the isotropic gels having equilibrium degrees of swelling was measured by systematically changing crosslinking density of gels. The results yielded D=(3.4±0.5)×10-6 C0.76±0.03e cm2/s, in accord with a scaling prediction. For each of the gels prepared and having a given Ce, the uniaxial stretching was applied, and the values D were investigated as a function of extension ratio α and direction β with respect to the stretching direction. The results gave D (α,Ce)=(3.4±0.5)×10-6 αx Cye cm2/s, where x=2/3 for β=0° and -1/4 for β=90°, and y=0.76, independent of α and β. The results clearly indicate that upon increasing α, D increases and decreases, respectively, in the direction parallel and perpendicular to the stretching direction, implying suppression and enhancement of the concentration fluctuations as a result of the network being stiffened and softened in the respective directions. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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