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Lee CL, Chan TS, Carlson A, Dalnoki-Veress K. Multiple droplets on a conical fiber: formation, motion, and droplet mergers. SOFT MATTER 2022; 18:1364-1370. [PMID: 35043822 DOI: 10.1039/d1sm01462e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Small droplets on slender conical fibers spontaneously move along the fiber due to capillary action. The droplet motion depends on the geometry of the cone, the surface wettability, the surface tension, the viscosity, and the droplet size. Here we study with experiments and numerical simulations, the formation, spontaneous motion, and the eventual merger, of multiple droplets on slender conical fibers as they interact with each other. The droplet size and their spacing on the fibre is controlled by the Plateau-Rayleigh instability after dip-coating the conical fiber. Once these droplets are formed on the fiber, they spontaneously start to move. Since droplets of different size move with different speeds, they effectively coarsen the droplet patterning by merging on the fiber. The droplet merging process affects locally the droplet speed and alters the spatiotemporal film deposition on the fiber.
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Affiliation(s)
- Carmen L Lee
- Department of Physics & Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada.
| | - Tak Shing Chan
- Mechanics Division, Department of Mathematics, University of Oslo, 0316 Oslo, Norway
| | - Andreas Carlson
- Mechanics Division, Department of Mathematics, University of Oslo, 0316 Oslo, Norway
| | - Kari Dalnoki-Veress
- Department of Physics & Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada.
- UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 75005 Paris, France
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2
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Li C, Lan C, Guo M, Wang N, Ma Y. Wicking-Driven Evaporation Self-Assembly of Carbon Nanotubes on Fabrics: Generating Controlled Orientational Structures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:13963-13970. [PMID: 33174745 DOI: 10.1021/acs.langmuir.0c02436] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nanostructures with orientational order exhibit excellent electrical and optical properties; however, their construction on complex fabrics is challenging. Here, we demonstrate the potential of wicking-driven evaporation self-assembly in the oriented arrangement of carbon nanotubes (CNTs) on fabrics. The solution-evaporation self-assembly in combination with the fabric wicking effect leads to convective flows along the fibers, which makes it possible to prepare orientational nanostructures over large fabric surface areas. The orientation of CNTs is controlled by the fluid drag force from the convective flow during drying, thus the interaction between the CNT and the solution is crucial. We show that the nanostructures of CNTs on fibers depend, for example, on the evaporation temperature, component concentration, and solution pH. Weakening the viscous connection of the fluid with CNTs can lead to an interesting eddy nanostructure of CNTs. The electrical conductivity of the assembled fabrics increases strongly with the degree of orientation and the assembly cycles of CNTs. In this work, the large-scale orientational order of nanomaterial achieved by wicking-driven evaporation self-assembly offers a new strategy for constructing three-dimensional oriented conductive networks in electronic textiles.
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Affiliation(s)
- Chenglong Li
- Key Laboratory of Textile Science & Technology of Ministry of Education, College of Textiles, Donghua University, Shanghai 201620, China
| | - Chuntao Lan
- Key Laboratory of Textile Science & Technology of Ministry of Education, College of Textiles, Donghua University, Shanghai 201620, China
| | - Min Guo
- Key Laboratory of Textile Science & Technology of Ministry of Education, College of Textiles, Donghua University, Shanghai 201620, China
| | - Ni Wang
- Key Laboratory of Textile Science & Technology of Ministry of Education, College of Textiles, Donghua University, Shanghai 201620, China
| | - Ying Ma
- Key Laboratory of Textile Science & Technology of Ministry of Education, College of Textiles, Donghua University, Shanghai 201620, China
- Innovation Center for Textile Science and Technology, Donghua University, Shanghai 200051, China
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3
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Zhang Q, Lin G, Yin J. Highly efficient fog harvesting on superhydrophobic microfibers through droplet oscillation and sweeping. SOFT MATTER 2018; 14:8276-8283. [PMID: 30320332 DOI: 10.1039/c8sm01688g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Water droplet transport on fibers is of great importance for achieving high water collection efficiency from fog. Here, we exploit a new droplet sliding mechanism to accelerate the droplet coalescence and collection for highly efficient fog harvesting by coating hydrophilic microfibers with superhydrophobic layers of assembled carbon nanoparticles. We find that during the initial water collection, unlike the pinned droplets having axisymmetric barrel shapes wrapped around uncoated microfibers, the hanging droplets on coated microfibers with non-wrapping clamshell shapes are highly mobile due to their lower contact hysteresis adhesion; these are observed to oscillate, coalesce, and sweep the growing droplets along the horizontally placed microfibers. The driving force for droplet transport is mainly ascribed to the coalescence energy release and fog flow. After introducing small gravity force by tilting coated microfibers with a small angle of 5°, we find that it can effectively drive the oscillating mobile droplets for directional transport by rapidly sweeping the droplets with a much higher frequency. Finally, the water collection rate from fog on uncoated microfibers over a prolonged duration is found to be improved over 2 times after superhydrophobic coating, and it is further enhanced over 5 times after a small tilting angle of 5°.
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Affiliation(s)
- Qiuting Zhang
- Applied Mechanics of Materials Laboratory, Department of Mechanical Engineering, Temple University, 1947 North 12th Street, Philadelphia, PA 19122, USA.
| | - Gaojian Lin
- Applied Mechanics of Materials Laboratory, Department of Mechanical Engineering, Temple University, 1947 North 12th Street, Philadelphia, PA 19122, USA.
| | - Jie Yin
- Applied Mechanics of Materials Laboratory, Department of Mechanical Engineering, Temple University, 1947 North 12th Street, Philadelphia, PA 19122, USA.
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4
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Affiliation(s)
- Ying Cui
- State
Key Laboratory of Chemical Engineering, College of Chemical and Biological
Engineering, Zhejiang University, Hangzhou 310027, China
| | - Dewen Li
- State
Key Laboratory of Chemical Engineering, College of Chemical and Biological
Engineering, Zhejiang University, Hangzhou 310027, China
| | - Hao Bai
- State
Key Laboratory of Chemical Engineering, College of Chemical and Biological
Engineering, Zhejiang University, Hangzhou 310027, China
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Xu T, Lin Y, Zhang M, Shi W, Zheng Y. High-Efficiency Fog Collector: Water Unidirectional Transport on Heterogeneous Rough Conical Wires. ACS NANO 2016; 10:10681-10688. [PMID: 27689385 DOI: 10.1021/acsnano.6b05595] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
An artificial periodic roughness-gradient conical copper wire (PCCW) can be fabricated by inspiration from cactus spines and wet spider silks. PCCW can harvest fog on periodic points of the conical surface from air and transports the drops for a long distance without external force, which is attributed to dynamic as-released energy generated from drop deformation in drop coalescence, in addition to both gradients of geometric curve (inducing Laplace pressure) and periodic roughness (inducing surface energy difference). It is found that the ability of fog collection can be related to various tilt-angle wires, thus a fog collector with an array system of PCCWs is further designed to achieve a continuous process of efficient water collection. As a result, the effect of water collection on PCCWs is better than previous results. These findings are significant to develop and design materials with water collection and water transport for promising application in fogwater systems to ease the water crisis.
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Affiliation(s)
- Ting Xu
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University (BUAA) , Beijing 100191, P. R. China
| | - Yucai Lin
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University (BUAA) , Beijing 100191, P. R. China
| | - Miaoxin Zhang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University (BUAA) , Beijing 100191, P. R. China
| | - Weiwei Shi
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University (BUAA) , Beijing 100191, P. R. China
| | - Yongmei Zheng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University (BUAA) , Beijing 100191, P. R. China
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Amrei MM, Venkateshan DG, D'Souza N, Atulasimha J, Tafreshi HV. Novel Approach to Measuring the Droplet Detachment Force from Fibers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:13333-13339. [PMID: 27993019 DOI: 10.1021/acs.langmuir.6b03198] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Determining the force required to detach a droplet from a fiber or from an assembly of fibers is of great importance to many applications. A novel technique is developed in this work to measure this force experimentally by using ferrofluid droplets in a magnetic field. Unlike previous methods reported in the literature, our technique does not require air flow or a mechanical object to detach the droplet from the fiber(s); therefore, it simplifies the experiment and also allows one to study the capillarity of the droplet-fiber system in a more isolated environment. In this article, we investigated the effects of the relative angle between intersecting fibers on the force required to detach a droplet from the fibers in the in-plane or out-of-plane direction. The in-plane and through-plane detachment forces were also predicted via numerical simulation and compared with the experimental results. Good agreement was observed between the numerical and experimental results. It was found that the relative angle between intersecting fibers has no significant effect on the detachment force in the out-of-plane direction. However, the detachment force in the in-plane direction depends strongly on the relative angle between the fibers, and it increases as this angle increases.
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Affiliation(s)
- M M Amrei
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University , Richmond, Virginia 23284-3015, United States
| | - D G Venkateshan
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University , Richmond, Virginia 23284-3015, United States
| | - N D'Souza
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University , Richmond, Virginia 23284-3015, United States
| | - J Atulasimha
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University , Richmond, Virginia 23284-3015, United States
| | - H Vahedi Tafreshi
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University , Richmond, Virginia 23284-3015, United States
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