关键词: Biomaterials · Bio-inspired surface · Oil-triggered wenzel-slippery transition · Superhydrophobicity ·Femtosecond laser

Abstract: Surface-tension-confined microfluidic devices are platforms for manipulating 2D droplets based on patterned surfaces with
special wettability. They have great potential for various applications, but are still in the early stages of development and
face some challenges that need to be addressed. This study, inspired by the Wenzel and slippery transition of rose petal,
develops a Patterned Oil-triggered Wenzel-slippery Surface (POWS) to examine the microfluidic devices. A laser-chemical
composite method is established to fabricate POWSs, which take rose-petal-like microstructures as wettability pattern and
a superamphiphobic surface as the background. The prepared POWSs switched between high adhesion superhydrophobic
state and the slippery liquid-infused surface state through adding or removing the lubricant oil. In the high adhesion
superhydrophobic state, the droplets can be sticked on the surface. In the slippery liquid-infused state, the droplet can slide
along the wettability pattern as the designed route. A POWS-based droplet reactor is further constructed, on which, the
droplets can be remotely controlled to move, mix and react, as required. Such a POWS, which manipulates droplets with
surface tension controlled by the switchable wettability patterns, would be a promising candidate to construct multiple
surface-tension-confined microfluidic devices. In addition, the fabrication technique and design principle proposed here
may aid the development of various field related to the bio-inspired surfaces, such as water collection, desalination and
high throughput analysis, etc.

Key words: Biomaterials · Bio-inspired surface · Oil-triggered wenzel-slippery transition · Superhydrophobicity · Femtosecond laser