Flexible hemline-shaped microfibers for liquid transport

ABSTRACT Directional liquid transport is important in both fundamental studies and industrial applications. Most existing strategies rely on the use of predesigned surfaces with

sophisticated microstructures that limit the versatility and universality of the liquid transport. Here we present a platform for liquid transport based on flexible microfluidic-derived

fibers with hemline-shaped cross-sections. These microfibers have periodic parallel microcavities along the axial direction, with sharp edges and wedge corners that enable unilateral pinning

and capillary rise of liquids. This structure enables directional liquid transport along hydrophilic substrates with the use of a single fiber. Alternatively, a pair of fibers enables

directional liquid transport along hydrophobic substrates or even without any additional substrate; the directional transport behavior applies to a wide range of liquids. We demonstrate the

use of these fibers in open microfluidics, water extraction and liquid transport along arbitrary three-dimensional paths. Our platform provides a facile and universal solution for

directional liquid transport in a range of different scenarios. Access through your institution Buy or subscribe This is a preview of subscription content, access via your institution ACCESS

OPTIONS Access through your institution Subscribe to this journal Receive 12 digital issues and online access to articles $119.00 per year only $9.92 per issue Learn more Buy this article *

Purchase on SpringerLink * Instant access to full article PDF Buy now Prices may be subject to local taxes which are calculated during checkout ADDITIONAL ACCESS OPTIONS: * Log in * Learn

about institutional subscriptions * Read our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS TWISTED FIBER MICROFLUIDICS: A CUTTING-EDGE APPROACH TO 3D SPIRAL DEVICES

Article Open access 22 January 2024 NANOFIBER SELF-CONSISTENT ADDITIVE MANUFACTURING PROCESS FOR 3D MICROFLUIDICS Article Open access 15 September 2022 MICROFLUIDIC MANIPULATION BY SPIRAL

HOLLOW-FIBRE ACTUATORS Article Open access 14 March 2022 DATA AVAILABILITY All data are available within the paper and its Supplementary Information. REFERENCES * Feng, S. et al.

Three-dimensional capillary ratchet-induced liquid directional steering. _Science_ 373, 1344–1348 (2021). Article  CAS  PubMed  Google Scholar  * Li, S. et al. Hydrophobic polyamide

nanofilms provide rapid transport for crude oil separation. _Science_ 377, 1555–1561 (2022). Article  CAS  PubMed  Google Scholar  * Fu, C., Gu, L., Zeng, Z. & Xue, Q. Simply adjusting

the unidirectional liquid transport of scalable janus membranes toward moisture-wicking fabric, rapid demulsification, and fast oil/water separation. _ACS Appl. Mater. Interfaces_ 12,

51102–51113 (2020). Article  CAS  PubMed  Google Scholar  * Cacucciolo, V. et al. Stretchable pumps for soft machines. _Nature_ 572, 516–519 (2019). Article  CAS  PubMed  Google Scholar  *

Dudukovic, N. A. et al. Cellular fluidics. _Nature_ 595, 58–65 (2021). Article  CAS  PubMed  Google Scholar  * Raux, P. S., Gravelle, S. & Dumais, J. Design of a unidirectional water

valve in _Tillandsia_. _Nat. Commun._ 11, 396 (2020). Article  CAS  PubMed  PubMed Central  Google Scholar  * Chen, H. et al. Continuous directional water transport on the peristome surface

of _Nepenthes alata_. _Nature_ 532, 85–89 (2016). Article  CAS  PubMed  Google Scholar  * Van Erp, R., Soleimanzadeh, R., Nela, L., Kampitsis, G. & Matioli, E. Co-designing electronics

with microfluidics for more sustainable cooling. _Nature_ 585, 211–216 (2020). Article  PubMed  Google Scholar  * Yafia, M. et al. Microfluidic chain reaction of structurally programmed

capillary flow events. _Nature_ 605, 464–469 (2022). Article  CAS  PubMed  Google Scholar  * Aleman, J., Kilic, T., Mille, L. S., Shin, S. R. & Zhang, Y. S. Microfluidic integration of

regeneratable electrochemical affinity-based biosensors for continual monitoring of organ-on-a-chip devices. _Nat. Protoc._ 16, 2564–2593 (2021). Article  CAS  PubMed  Google Scholar  *

Battat, S., Weitz, D. A. & Whitesides, G. M. An outlook on microfluidics: the promise and the challenge. _Lab Chip_ 22, 530–536 (2022). Article  CAS  PubMed  Google Scholar  * Hou, X. et

al. Dynamic air/liquid pockets for guiding microscale flow. _Nat. Commun._ 9, 733 (2018). Article  PubMed  PubMed Central  Google Scholar  * Kong, T., Shum, H. C. & Weitz, D. A. The

fourth decade of microfluidics. _Small_ 16, 2000070 (2020). Article  CAS  Google Scholar  * Cira, N. J., Benusiglio, A. & Prakash, M. Vapour-mediated sensing and motility in

two-component droplets. _Nature_ 519, 446–450 (2015). Article  CAS  PubMed  Google Scholar  * Malinowski, R., Parkin, I. P. & Volpe, G. Nonmonotonic contactless manipulation of binary

droplets via sensing of localized vapor sources on pristine substrates. _Sci. Adv._ 6, eaba3636 (2020). Article  CAS  PubMed  PubMed Central  Google Scholar  * Lagubeau, G., Le Merrer, M.,

Clanet, C. & Quéré, D. Leidenfrost on a ratchet. _Nat. Phys._ 7, 395–398 (2011). Article  CAS  Google Scholar  * Ichimura, K., Oh, S.-K. & Nakagawa, M. Light-driven motion of liquids

on a photoresponsive surface. _Science_ 288, 1624–1626 (2000). Article  CAS  PubMed  Google Scholar  * Xu, W. et al. Triboelectric wetting for continuous droplet transport. _Sci. Adv._ 8,

eade2085 (2022). Article  CAS  PubMed  PubMed Central  Google Scholar  * Li, W., Tang, X. & Wang, L. Photopyroelectric microfluidics. _Sci. Adv._ 6, eabc1693 (2020). Article  CAS  PubMed

  PubMed Central  Google Scholar  * Kwon, G. et al. Visible light guided manipulation of liquid wettability on photoresponsive surfaces. _Nat. Commun._ 8, 14968 (2017). Article  PubMed 

PubMed Central  Google Scholar  * Lv, J. A. et al. Photocontrol of fluid slugs in liquid crystal polymer microactuators. _Nature_ 537, 179–184 (2016). Article  CAS  PubMed  Google Scholar  *

Parker, A. R. & Lawrence, C. R. Water capture by a desert beetle. _Nature_ 414, 33–34 (2001). Article  CAS  PubMed  Google Scholar  * Dai, H., Dong, Z. & Jiang, L. Directional

liquid dynamics of interfaces with superwettability. _Sci. Adv._ 6, eabb5528 (2020). Article  CAS  PubMed  Google Scholar  * Chu, K.-H., Xiao, R. & Wang, E. N. Uni-directional liquid

spreading on asymmetric nanostructured surfaces. _Nat. Mater._ 9, 413–417 (2010). Article  CAS  PubMed  Google Scholar  * Ju, J. et al. A multi-structural and multi-functional integrated fog

collection system in cactus. _Nat. Commun._ 3, 1247 (2012). Article  PubMed  Google Scholar  * Li, J. et al. Topological liquid diode. _Sci. Adv._ 3, eaao3530 (2017). Article  PubMed 

PubMed Central  Google Scholar  * De Jong, E., Wang, Y., Den Toonder, J. M. J. & Onck, P. R. Climbing droplets driven by mechanowetting on transverse waves. _Sci. Adv._ 5, eaaw0914

(2019). Article  PubMed  PubMed Central  Google Scholar  * Liu, M., Wang, S. & Jiang, L. Nature-inspired superwettability systems. _Nat. Rev. Mater._ 2, 17036 (2017). Article  CAS 

Google Scholar  * Shi, Z., Tang, Z., Xu, B., Jiang, L. & Liu, H. Bioinspired directional liquid transport induced by the corner effect. _Nano Res._ 16, 3913–3923 (2023). Article  Google

Scholar  * Luan, K. et al. Spontaneous directional self‐cleaning on the feathers of the aquatic bird _Anser cygnoides domesticus_ induced by a transient superhydrophilicity. _Adv. Funct.

Mater._ 31, 2010634 (2021). Article  CAS  Google Scholar  * Tang, Z. et al. Bioinspired robust water repellency in high humidity by micro-meter-scaled conical fibers: toward a long-time

underwater aerobic reaction. _J. Am. Chem. Soc._ 144, 10950–10957 (2022). Article  CAS  PubMed  Google Scholar  * Meng, Q. et al. Controlling directional liquid transport on dual cylindrical

fibers with oriented open‐wedges. _Adv. Mater. Interfaces_ 9, 2101749 (2022). Article  CAS  Google Scholar  * Zheng, Y. et al. Directional water collection on wetted spider silk. _Nature_

463, 640–643 (2010). Article  CAS  PubMed  Google Scholar  * Nunes, J. K. et al. Fabricating shaped microfibers with inertial microfluidics. _Adv. Mater._ 26, 3712–3717 (2014). Article  CAS

  PubMed  Google Scholar  * Shang, L. et al. Spinning and applications of bioinspired fiber systems. _ACS Nano_ 13, 2749–2772 (2019). Article  CAS  PubMed  Google Scholar  * Tian, Y. et al.

Large-scale water collection of bioinspired cavity-microfibers. _Nat. Commun._ 8, 1080 (2017). Article  PubMed  PubMed Central  Google Scholar  * Li, J., Li, J., Sun, J., Feng, S. &

Wang, Z. Biological and engineered topological droplet rectifiers. _Adv. Mater._ 31, 1806501 (2019). Article  Google Scholar  * Liu, M. et al. Inhibiting random droplet motion on hot

surfaces by engineering symmetry‐breaking Janus‐mushroom structure. _Adv. Mater._ 32, 1907999 (2020). Article  CAS  Google Scholar  * Zhang, C. et al. Bioinspired anisotropic slippery cilia

for stiffness-controllable bubble transport. _ACS Nano_ 16, 9348–9358 (2022). Article  CAS  PubMed  Google Scholar  * Wu, S. et al. Superhydrophobic photothermal icephobic surfaces based on

candle soot. _Proc. Natl Acad. Sci. USA_ 117, 11240–11246 (2020). Article  CAS  PubMed  PubMed Central  Google Scholar  * Oh, I. et al. Dynamically actuated liquid‐infused poroelastic film

with precise control over droplet dynamics. _Adv. Funct. Mater._ 28, 1802632 (2018). Article  Google Scholar  * Xu, B. et al. Electrochemical on‐site switching of the directional liquid

transport on a conical fiber. _Adv. Mater._ 34, 2200759 (2022). Article  CAS  Google Scholar  * Li, C. et al. Bioinspired inner microstructured tube controlled capillary rise. _Proc. Natl

Acad. Sci. USA_ 116, 12704–12709 (2019). Article  CAS  PubMed  PubMed Central  Google Scholar  * Li, J. et al. Nature-inspired reentrant surfaces. _Prog. Mater Sci._ 133, 101064 (2023).

Article  Google Scholar  * Yu, Y. et al. Simple spinning of heterogeneous hollow microfibers on chip. _Adv. Mater._ 28, 6649–6655 (2016). Article  CAS  PubMed  Google Scholar  * Du, X. Y.,

Li, Q., Wu, G. & Chen, S. Multifunctional micro/nanoscale fibers based on microfluidic spinning technology. _Adv. Mater._ 31, 1903733 (2019). Article  CAS  Google Scholar  * Paulsen, K.

S., Di Carlo, D. & Chung, A. J. Optofluidic fabrication for 3D-shaped particles. _Nat. Commun._ 6, 6976 (2015). Article  PubMed  Google Scholar  * Amini, H. et al. Engineering fluid flow

using sequenced microstructures. _Nat. Commun._ 4, 1826 (2013). Article  PubMed  Google Scholar  * Chao, Y. & Shum, H. C. Emerging aqueous two-phase systems: from fundamentals of

interfaces to biomedical applications. _Chem. Soc. Rev._ 49, 114–142 (2020). Article  CAS  PubMed  Google Scholar  * Mak, S. Y., Li, Z., Frere, A., Chan, T. C. & Shum, H. C. Musical

interfaces: visualization and reconstruction of music with a microfluidic two-phase flow. _Sci. Rep._ 4, 6675 (2014). Article  CAS  PubMed  PubMed Central  Google Scholar  * Sauret, A. &

Shum, H. C. Beating the jetting regime. _Int. J. Nonlinear Sci. Numer. Simul._ 13, 351–362 (2012). Article  Google Scholar  * Weislogel, M. M. & Lichter, S. Capillary flow in an

interior corner. _J. Fluid Mech._ 373, 349–378 (1998). Article  Google Scholar  * Weislogel, M. M. Compound capillary rise. _J. Fluid Mech._ 709, 622–647 (2012). Article  Google Scholar  *

Wang, K., Sanaei, P., Zhang, J. & Ristroph, L. Open capillary siphons. _J. Fluid Mech._ 932, R1 (2022). Article  CAS  Google Scholar  * Liu, Y. et al. Bionic jaw-like micro one-way valve

for rapid and long-distance water droplet unidirectional spreading. _Nano Lett._ 23, 5696–5704 (2023). Article  CAS  PubMed  Google Scholar  * Washburn, E. W. The dynamics of capillary

flow. _Phy. Rev._ 17, 273–283 (1921). Article  Google Scholar  * Courbin, L., Bird, J. C., Reyssat, M. & Stone, H. A. Dynamics of wetting: from inertial spreading to viscous imbibition.

_J. Phys. Condens. Matter_ 21, 464127 (2009). Article  CAS  PubMed  Google Scholar  * Zhang, L. et al. Bioinspired unidirectional liquid transport micro-nano structures: a review. _J. Bionic

Eng._ 18, 1–29 (2021). Article  CAS  Google Scholar  Download references ACKNOWLEDGEMENTS This work was supported by the National Natural Science Foundation of China with grants T2225003

(Y.Z.), 22202050 (C.Y.), 32271383 (L.S.) and 52073060 (Y.Z.), and the National Key Research and Development Program of China with grant 2020YFA0908200 (Y.Z.). AUTHOR INFORMATION Author notes

* These authors contributed equally: Chaoyu Yang, Yunru Yu. AUTHORS AND AFFILIATIONS * Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science

and Medical Engineering, Southeast University, Nanjing, China Chaoyu Yang, Yunru Yu & Yuanjin Zhao * Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health),

Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, China Chaoyu Yang, Yunru Yu & Yuanjin Zhao * Zhongshan-Xuhui Hospital, and the Shanghai Key Laboratory of Medical

Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology (Institutes of Biomedical Sciences), Fudan University, Shanghai, China

Luoran Shang Authors * Chaoyu Yang View author publications You can also search for this author inPubMed Google Scholar * Yunru Yu View author publications You can also search for this

author inPubMed Google Scholar * Luoran Shang View author publications You can also search for this author inPubMed Google Scholar * Yuanjin Zhao View author publications You can also search

for this author inPubMed Google Scholar CONTRIBUTIONS Y.Z. and L.S. conceived the idea. C.Y. designed the experiments. C.Y. and Y.Y. conducted the experiments. C.Y. and L.S. analyzed the

data. C.Y., L.S. and Y.Z. wrote the paper. CORRESPONDING AUTHORS Correspondence to Luoran Shang or Yuanjin Zhao. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing

interests. PEER REVIEW PEER REVIEW INFORMATION _Nature Chemical Engineering_ thanks Huan Liu and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

ADDITIONAL INFORMATION PUBLISHER’S NOTE Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. SUPPLEMENTARY INFORMATION

SUPPLEMENTARY INFORMATION Supplementary Tables 1 and 2, Figs. 1–21 and Discussion. SUPPLEMENTARY VIDEO 1 Jet dynamics under piezoelectric vibration. SUPPLEMENTARY VIDEO 2 Computational fluid

dynamics simulation of the hemline-shaped jet dynamics. SUPPLEMENTARY VIDEO 3 Liquid transport behavior along a hemline-shaped and straight fiber. SUPPLEMENTARY VIDEO 4 High-speed digital

images of the pinning and spreading behavior on a hydrophilic substrate. SUPPLEMENTARY VIDEO 5 Applications of hemline-shaped fibers. SOURCE DATA SOURCE DATA FIG. 1 Statistical source data.

SOURCE DATA FIG. 2 Statistical source data. SOURCE DATA FIG. 3 Statistical source data. SOURCE DATA FIG. 4 Statistical source data. RIGHTS AND PERMISSIONS Springer Nature or its licensor

(e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted

manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law. Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Yang, C.,

Yu, Y., Shang, L. _et al._ Flexible hemline-shaped microfibers for liquid transport. _Nat Chem Eng_ 1, 87–96 (2024). https://doi.org/10.1038/s44286-023-00001-5 Download citation * Received:

11 April 2023 * Accepted: 20 November 2023 * Published: 11 January 2024 * Issue Date: January 2024 * DOI: https://doi.org/10.1038/s44286-023-00001-5 SHARE THIS ARTICLE Anyone you share the

following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently available for this article. Copy to clipboard Provided by the Springer

Nature SharedIt content-sharing initiative