writer：Lieshuang Zhong, Huan Chen, Lingmei Zhu, Maolin Zhou, Lei Zhang, Shaomin Wang, Xuefeng Han, Yongping
keywords：self-propelling
source：期刊
Issue time：2022年

Constructing surface wetting gradients usually involves complex physical or

chemical methods. Here, a novel Gradient-Janus wire (GJW) can be designed

based on the theory of newly Liquid Confined Modification (LCM). In LCM

theory, reaction difference will be generated by the confinement of reac-

tion solution, which constructs wettability discrepancy on the same curve

surface. Thus a unique continuous Gradient-Janus wetting region can be

constructed in a long range on a 1D wire. It is demonstrated that GJW can

propel water droplets to transport the distance of ≈73 mm in 0.9 s, and liquid

bridge to 85 mm (the longest among this kind of study) in 0.79 s with peak

velocity high up to 237 mm s ?1 (over 20 times faster than droplet transport on

surface of Sarracenia trichome). The mechanism is attributed to cooperation

between imbalanced Laplace pressure and surface tension force to generate

the driving force act on droplet, liquid bridge, or column transport, respec-

tively. LCM directs the large-scale facile fabrication of GJWs within 20 s. A

large-scale GJW array can achieve the high-efficient transport of water droplet

in a wide volume range (few μL to 1 mL), making it potential in fogwater

harvesting.