Spontaneous Directional Transportation Surface of Water Droplet and Gas Bubble: A Review

Abstract

The spontaneous directional transportation (SDT) of water and gas has functions such as efficient water collection, enhanced heat transfer, underwater drag reduction, and so on, having great application prospects in aerospace and navigation fields. Therefore, it is important to efficiently prepare spontaneous directional water droplet transportation (SDWT) surfaces and spontaneous directional gas bubble transportation (SDBT) surfaces and apply them in different fields. In recent years, researchers have used biological structures as the basis for their studies and have continued to analyze the SDT transport mechanism in depth, aiming to find more efficient transportation methods. In this review, we first summarize the important basic theories related to fluid transportation. Then, the related methods and the limitations corresponding to SDWT and SDBT are introduced and discussed. In addition, we review the applications of SDWT and SDBT. Finally, we highlight the challenges and future perspectives of SDWT and SDBT.

Keywords

• spontaneous directional transportation
• wettability gradient
• shape gradient
• cooperative surface