Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, International Research Institute for Multidisciplinary Science, Beihang University, Beijing, 100191, People's Republic of China.
Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Centre for High-efficiency Display and Lighting Technology, School of Materials and Engineering, Collaborative Innovation Centre of Nano Functional Materials and Applications, Henan University, Kaifeng, 475004, People's Republic of China.
J Am Chem Soc. 2020 Apr 1;142(13):6111-6116. doi: 10.1021/jacs.9b13286. Epub 2020 Mar 19.
Self-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 (∼520 μm/s). The velocity is even faster on a wet fiber by two times (∼47.34 mm/s). Here, the Laplace pressure difference () 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 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.
自主定向液体输运 (SDLT) 在许多天然基质上都有观察到，这是一种利用周围液体为局部环境提供更好栖息地的有效策略。受此启发，人们开发了各种能够实现 SDLT 的人工材料。然而，液体的输运速度通常非常低（约 3-30 μm/s），这限制了其实际应用。在此，我们开发了具有凹面的新型金字塔结构纤维（P 凹面纤维，PCCF），实现了超快 SDLT。具体而言，在干燥的三 PCCF 上，液体的输运速度可达约 28.79 mm/s，比表面上的速度快 50 多倍（约 520 μm/s）。在湿纤维上的速度甚至更快两倍（约 47.34 mm/s）。在这里，由锥形结构引起的拉普拉斯压差（）决定了液体的输运方向。据推测，凹面赋予的毛细上升以及定向微脊/微槽和减小的横截面积引起的增强都会加速 PCCF 表面上的 SDLT。因此，PCCF 采用了一种不同的液体输运策略，具有凸形前进接触角，与传统的锥形纤维不同。此外，所开发的 PCCF 还适用于水下超快 SDLT 的油。我们设想，这一结果将为制造用于微流控和液体处理的纤维系统开辟新的视角。
