2019 Fiscal Year Final Research Report
Molecular Mechanism of Tom's Effect by Self-Assembly of Surfactant Molecules
| Project/Area Number |
17K14610
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Thermal engineering
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| Research Institution | Keio University (2019)
Kindai University (2017-2018) |
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Principal Investigator |
Arai Noriyoshi 慶應義塾大学, 理工学部(矢上), 准教授 (80548363)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | 界面活性剤 / ミセル / 自己集合 / 抵抗低減 / 分子シミュレーション |
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| Outline of Final Research Achievements |
To investigate the molecular mechanism of the Toms effect, coarse-grained molecular simulations were performed to reproduce the behavior of surfactant aqueous solutions in a tube flow. When the hydrophilic wall of the tube, shear thinning is observed regardless of the concentration of the surfactants, whereas in the hydrophobic tube, Newtonian fluid-like behavior and shear thickening are observed. The tube diameter was extended to reproduce the behavior of the surfactant solution in the turbulent and laminar-to-turbulence transition regions. A shear-induced structure, in which rod-like micelles clustered near the center of the tube, was observed, suggesting that the change in the structure affected the drag reduction.
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| Free Research Field |
分子シミュレーション
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| Academic Significance and Societal Importance of the Research Achievements |
界面活性剤水溶液の粘度と自己集合構造の関係性を分子スケールで明らかにした．また円管内壁の化学的性質を変えることで，界面活性剤が形成する集合構造が変化し，結果として粘度の制御が可能であることを示した．抵抗低減効果は流れの状態（層流，乱流，遷移領域）に大きく依存したため，集合構造の振る舞いが関与している可能性がある．また水溶液内で特殊な自己集合構造を形成する物質として，Janus粒子系についても粒子デザインやアスペクト比，濃度をパラメータとして，自己集合構造と粘性挙動の関係を調べた．その結果，様々な自己集合構造が形成されたものの，粘度については集合体の平均会合数のみで見積もれることを明らかにした．
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