ja9b13286_si_001.pdf (1.07 MB)
Ultrafast Self-Propelled Directional Liquid Transport on the Pyramid-Structured Fibers with Concave Curved Surfaces
journal contribution
posted on 2020-03-18, 20:29 authored by Binbin Hu, Zhongfeng Duan, Bojie Xu, Kejie Zhang, Zhongxue Tang, Cong Lu, Meijin He, Lei Jiang, Huan LiuSelf-propelled directional
liquid transport (SDLT) has been observed
on many natural substrates, serving as an efficient strategy to utilize
surrounding liquids for a better habitat to the local environment.
Drawing inspiration, various artificial materials capable of SDLT
have been developed. However, the liquid transport velocity is normally
very low (ca. 3–30 μm/s), which limits its practical
applications. Herein, we developed novel pyramid-structured fibers
with concave curved surfaces (P-concave curved-fiber, PCCF), which
enable the ultrafast SDLT. Specifically, the liquid transport velocity
can be up to ∼28.79 mm/s on a dry tri-PCCF, over 50 times faster
than that on the surface of Sarracenia trichome (∼520
μm/s). The velocity is even faster on a wet fiber by two times
(∼47.34 mm/s). Here, the Laplace pressure difference (FL) induced by the tapered structure determines
the liquid transport direction. It is proposed that both the capillary
rises imparted by the concave curved surfaces and the oriented microridges/valleys
and the enhanced FL aroused by the reduced
cross-sectional area accelerate the SDLT on surfaces of the PCCFs.
Consequently, the PCCF takes a different liquid transport strategy
with a convex-shaped advancing meniscus, differing from that on traditional
conical fibers. Moreover, the as-developed PCCF is also applicable
for underwater ultrafast SDLT of oil. We envision that the result
will open a new perspective for fabricating a fibrous system for microfluidic
and liquid manipulation.