Water droplet bouncing dynamics

Abstract

Droplet bouncing on surfaces has long been observed in nature and industry, which is rather intriguing and instructive for related technology development. Recent decades have witnessed significant progress on the mechanism exploring, device development, and application demonstrations. In this review, we focus on the recent progresses that aim at introducing the phenomena, revealing the underlying physics, and promoting the potential applications of water droplet bouncing on various solid and soft surfaces like hydrophobic/hydrophilic/heated solid surfaces and liquid film/bath/droplet. The water droplet bouncing dynamics is highly dependent on the liquid properties, surface characteristics and ambient pressure. The absence of droplet/surface contact, as the key point for droplet bouncing, can be realized by lowering the Weber number of droplet and designing hydrophobic surfaces to reduce the droplet-surface contact, actively maintaining the air/vapor film by heating the solid surface above the Leidenfrost point, vibrating the liquid bath, applying electric/magnetic/pressure fields, etc. Moreover, the comprehensive understanding of droplet bouncing has promoted the development of numerous advanced surfaces technologies, including surface self-cleaning, directional droplet transportation, heat transfer enhancement, droplet logic gate, electrical generation and so on. Finally, the future directions for research and application are outlined and discussed. • Water droplet bouncing on various solid and liquid surfaces are summarized. • The underlying physics of water droplet bouncing dynamics is discussed. • The emerging droplet-based applications are introduced. • The future directions for the research and application of water droplet bouncing are outlined.