Novel Self-Assembly Process Using Nanofluid as Quasi Convective Medium

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H04552
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Properties in chemical engineering process/Transfer operation/Unit operation
• Research Institution: Kyoto University
• Principal Investigator: Miyahara Minoru 京都大学, 工学研究科, 教授 (60200200)
• Co-Investigator(Kenkyū-buntansha): 渡邉 哲 京都大学, 工学研究科, 講師 (80402957)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: コロイド結晶 / ナノフルイド / 自己組織化 / 移流集積法 / 相互作用力測定

Outline of Final Research Achievements

We fabricated colloidal films of microspheres using such a nanofluid suspension and performed in-situ measurements of the interaction forces between the microspheres in the nanofluid. The obtained results confirm that the use of the nanofluid results in a monolayer with a higher degree of order than that in the case of films formed using pure water. Further, the optimal size of the nanoparticles is determined based on the balance between their physical size and the Debye length. We also show that the lodging of the nanoparticles between the microspheres decreases both the lubrication force and the friction force between them. Thus, in this study, we show that a nanofluid can be used in the self-assembly process for improving the regularity of the fabricated colloidal particle arrays, as it inhibits the aggregation of the particles and limits the lubrication and friction forces between them.

Free Research Field

コロイド分散系工学

Academic Significance and Societal Importance of the Research Achievements

コロイド結晶は，微粒子が規則的に配列した集合体であり，その特異な光学特性から構造色材料などへの応用が期待されている。しかし，その作製方法は単純ではなく，簡便に，かつ大面積に作製しようとすると，どうしても欠陥が生じ，それが材料の特性を損ねてしまう。本研究は，コロイド結晶の作製時に，用いる微粒子よりもさらに小さなナノ粒子を添加するだけで，欠陥を減少させられることを明らかにし，そのメカニズムについても詳細に検討した。本研究で明らかにした手法によって，より欠陥の少ない構造形成が可能になると期待される。