Wetting of Real Surface with Chemical and Physical Defects

2023 Fiscal Year Final Research Report

• Project/Area Number: 18K03554
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13040:Biophysics, chemical physics and soft matter physics-related
• Research Institution: Asahikawa Medical College
• Principal Investigator: Mayama Hiroyuki 旭川医科大学, 医学部, 教授 (70360948)
• Project Period (FY): 2018-04-01 – 2024-03-31
• Keywords: 濡れ現象 / ピン止め現象 / 汚れた表面 / 濡れと撥水の確率

Outline of Final Research Achievements

We have studied wetting phenomena on real surface. Among the wetting phenomena on real surfaces, it has been reported that the surface of a termite wing shows dual wetting, where dual wetting is that wetting for small waterdrops (fog) and repelling behavior for large waterdrops (raindrops), while it shows wetting or repelling behaviors for intermediate-sized waterdrops (drizzle). Since the termite wing has the surface covered by long and short hairs, we consider the contributions of kinetic energy of waterdrops, adhesion energy between waterdrops and these hairs, dissipation energy due to viscosity of different-sized waterdrops impacting onto the surface. As a result, we have succeeded the dual wetting. Furthermore, we have found that the wetting or repelling behaviors for the intermediate-sized waterdrops can be described by the Boltzmann factor and the threshold energy between wetting and repelling behaviors.

Free Research Field

ソフトマター物理学

Academic Significance and Societal Importance of the Research Achievements

上記の二重濡れを明らかにした理論的手法は超撥水表面構造の特徴的なスケールと水滴の大きさの関係から、水滴が付着するのか、弾かれるのかを説明することができる。換言すると、表面構造の特徴的なスケールの下限値に対して、付着する水滴の大きさ、付着するか弾かれるかの大きさ、弾かれる大きさがあることを見出した。また、中間的な大きさ確率から表面構造のスケールと、付着するか弾かれるを決めるエネルギー閾値が一定の関係があることを明らかにしたので、霧を捕集する等の基材、わざと霧で濡らしてマクロな水をはじく表面の設計指針となる。