| Project/Area Number |
08455007
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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 |
Applied materials science/Crystal engineering
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| Research Institution | University of Tokyo |
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Principal Investigator |
TANAKA Hajime University of Tokyo, Institute of Industrial Science, Associate Professor, 生産技術研究所, 助教授 (60159019)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Jun University of Tokyo, Institute of Industrial Science, Research Associate, 生産技術研究所, 助手 (10200809)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥8,200,000 (Direct Cost: ¥8,200,000)
Fiscal Year 1997: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1996: ¥6,600,000 (Direct Cost: ¥6,600,000)
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| Keywords | Viscoelastic / Phase Separation / Polymer Solution / Dynamic asymmetry / Pattern Formation / Critical Phenomena / Simulation / Hydrodynamics / 動的対称性 / 粘弾性 / ダイナミクス / シミュレーション / 緩和現象 / ガラス転移 / 粘弾性相分離 / 相分離ダイナミクス / ミセル溶液 / 粘弾性緩和 / 流体力学モデル |
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| Research Abstract |
We have improved a general model of phase separation in isotropic condensed matter, namely, a viscoelastic model. We propose that the bulk mechanical relaxation modulus that has so far been ignored in previous theories plays an important role in viscoelastic phase separation in addition to the shear relaxation modulus. In polymer solutions, for example, attractive interactions between polymers under a poor-solvent condition likely cause transient gel-like behavior, which makes both bulk and shear modes active. Although such attractive interaction between molecules of the same component exist universally in the two phase region of a mexture, the stress arising from attractive interactions is asymmetrically diveded between the components only in dynamically asymmetric mixtures such as polymer solutions and colloidal suspensions. Thus the interaction network between the slower components, which can store the elastic energy against its deformation through bulk and shear moduli, is formed. This unique feature originates from the difference in mobility between two components of a mixture. It is the bulk relaxation modulus associates with this interaction network that is primarily responsible for the appearance of the sponge structure to viscoelastic phase separation and the phase inversion. It suppresses short-wavelength concentration fluctuation in the initial stage, and causes the volume shirinking of a more viscoelastic phase. We also propose a simple general law of stress division between the two components of a mixture, as a straightforward extension including this new effect is a general model that can describe all types of isotropic phase separation. The physical origin of volume shrinking behavior during viscoelastic phase separation and the universality of the resulting sponge like structure are also discussed.
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