Computational study of contact angles in wettability based on nano-modelings of local structures at interfaces

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K17762
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Composite materials/Surface and interface engineering; Thin film/Surface and interfacial physical properties
• Research Institution: Japan Advanced Institute of Science and Technology
• Principal Investigator: Hongo Kenta 北陸先端科学技術大学院大学, 情報社会基盤研究センター, 准教授 (60405040)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 表面・界面物性 / 濡れ性 / シミュレーション工学 / 化学物理 / 第一原理計算 / モデリング

Outline of Final Research Achievements

Wettability is a macroscopic quantity, which is thought of as impossible to be evaluated by ab initio simulations. But recently, ab initio attempts have been made on evaluating the energies by modeling the interface between water and solid surfaces. Such previous studies, however, considered few interface models for semiconductors and oxides. In this project we investigate wettability of copper-water interface as a typical meta-water one, and establish a new structure modeling considering a number of cluster sizes and structures to model the interface considering local structures. We applied density functional theory (DFT) simulations to evaluate the energies in the approximated Young's equation and take the Boltzmann average over the cluster to give an ensemble value of contact angle. Our "ab intio" contact angle was found to agree well with the experiments. We should be able to apply our established "nano-modeling" scheme to explore interfaces appropriate for desirable wettability.

Free Research Field

マテリアルズ・インフォマティクス

Academic Significance and Societal Importance of the Research Achievements

表面の濡れ性制御は、工学の様々な分野で活用される重要な課題である。身近な例としては、衣料の防水加工や自動車のフロントガラスやボディーの撥水処理などが挙げられる。工業的な観点からは、プリント基板上でのはんだ付けや、近年では、電気化学反応における濡れ性と触媒活性との関係を示す報告もなされ、単に濡れ性現象の工業的応用のみならず、他の機能との関係性からも、濡れ異性現象の理解は重要な意義を持つ。本研究で濡れ性接触角の第一原理算定スキームを確立できれば、対象固体表面に元素置換を施した表面系を幅広く計算し、所望の表面系を探索可能になると期待される。