writer：Lieshuang Zhong, Huan Chen, Lingmei Zhu, Lei Zhang, Shaomin Wang, Yongping Hou, and Yongmei Zheng*
keywords：bubble，gas collecting
source：期刊
Issue time：2022年

Underwater bubble is vital to various applications and many technologies are

applied for realizing efficient interfacial bubble generating. Here, the unique

underwater bubble generating by the thorn of pitaya is reported. Extensive

bubbles are generated underwater within few seconds on the thorn surface.

Microbumps and dual-scale ribs grow on the thorn surface, constructing the

unique dual-scale groove configuration along the thorn surface. Microbumps

equip groove with width gradient. The mechanism of how geometric con-

figuration of groove and surface wettability affect the bubble generating is

investigated. Bioinspired study shows that groove configuration can gen-

erate bubble within 2 ms by reassembling gas column within groove, which

lowers the energy barrier of bubble generating and accelerated gas molecular

diffusion toward bubble. Dual-scale groove is beneficial for strengthening

surface hydrophobicity and is favorable for reassembling. Besides, width

gradient induces the discrepancy of interface curvature along the groove and

further accelerates the bubble generating. Accordingly, the dual-scale gradient

groove can speed up bubble generating by ≈800%. Especially, the biomimetic

combinational groove can realize enhanced underwater gas collection. This

research reveals a new mechanism of fast bubble generating which is of great

potential for the applications based on underwater bubbles.