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Zhan D, Chen X, Xia Y, He S, Huang J, Guo Z. Improved Fog Collection on a Hybrid Surface with Acylated Cellulose Coating. ACS APPLIED MATERIALS & INTERFACES 2024; 16:27657-27667. [PMID: 38747627 DOI: 10.1021/acsami.4c04456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Fog collection serves as an efficient method to alleviate water scarcity in foggy, water-stressed regions. Recent research has focused on constructing a hybrid surface to enhance fog collection efficiency, with one approach being the prevention of liquid film formation at hydrophilic sites. Inspired by the desert beetle, a coating (10-MCC) made by partially acylating microcrystalline cellulose (MCC) exhibits hydrophilic sites alongside a hydrophobic skeleton enabling rapid droplet capture despite its overall hydrophobicity. The captured droplets quickly coalesce into a large droplet driven by the wetting gradient created by the hydrophobic backbone and hydrophilic sites. To achieve greater fog collection efficiency, a hydrophobic-superhydrophobic hybrid surface is formed by combining a coating of 10-MCC with a superhydrophobic surface. The construction of superhydrophobic surfaces typically involves creating a rough surface with a distinctive structure produced by the anodization technique and modifying it with stearic acid. The superhydrophobic surface exhibits excellent corrosion resistance and mechanical stability. Moreover, the hybrid surface shows high efficiency in fog collection, with a tested maximum efficiency of approximately 1.5092 g/cm2/h, 1.77 times that of the original Al sheets. The results demonstrate a remarkable enhancement in fog collection capacity. Furthermore, this work serves as an inspiration for the low-cost and innovative design of engineered surfaces for efficient fog collection.
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Affiliation(s)
- Danyan Zhan
- School of Materials Science and Engineering, Hubei University, Wuhan 430062, China
| | - Xionggang Chen
- School of Materials Science and Engineering, Hubei University, Wuhan 430062, China
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China
| | - Yu Xia
- School of Materials Science and Engineering, Hubei University, Wuhan 430062, China
| | - Shaojun He
- School of Materials Science and Engineering, Hubei University, Wuhan 430062, China
| | - JinXia Huang
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China
| | - Zhiguang Guo
- School of Materials Science and Engineering, Hubei University, Wuhan 430062, China
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China
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Chang LH, Kumar S. Capillary Filling in Open Rectangular Microchannels with a Spatially Varying Contact Angle. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:18526-18536. [PMID: 38054451 DOI: 10.1021/acs.langmuir.3c02865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Capillary flow in microchannels is important for many technologies, such as microfluidic devices, heat exchangers, and fabrication of printed electronics. Due to a readily accessible interior, open rectangular microchannels are particularly attractive for these applications. Here, we develop modifications of the Lucas-Washburn model to explore how a spatially varying contact angle influences capillary flow in open rectangular microchannels. Four cases are considered: (i) different uniform contact angles on channel sidewalls and channel bottom, (ii) contact angles varying along the channel cross section, (iii) contact angle varying monotonically along the channel length, and (iv) contact angle varying periodically along the channel length. For case (i), it is found that the maximum filling velocity is more sensitive to changes in the wall contact angle. For case (ii), the contact angles can be averaged to transform the problem into that of case (i). For case (iii), the time evolution of the meniscus position no longer follows the simple square-root law at short times. Finally, for case (iv), the problem is well described by using a uniform contact angle that is a suitable average. These results provide insights into how to design contact-angle variations to control capillary filling and into the influence of naturally occurring contact-angle variations on capillary flow.
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Affiliation(s)
- Li-Hsuan Chang
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Satish Kumar
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Gao J, Song Y, Huang L, Luo H, Dong X, Wang C, Duan JA. Laser-Textured Hybrid Brass Pattern Array Surface for High-Efficiency Fog Collection. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 38037240 DOI: 10.1021/acs.langmuir.3c03056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Fog collection holds promise for addressing water shortage. However, the conventional fabrication of fog collection devices, normally chemical methods, suffers many challenges, such as complicated preparation and environmental issues. Herein, we proposed a green fabrication strategy to construct superhydrophobic/hydrophilic surfaces on the brass substrate via the combination of laser fabrication and heat treatment. The wettability of brass is directly dictated by the laser process parameters. The different superhydrophobic/hydrophilic hybrid pattern surface with a rectangular/triangular array was designed for an optimal fog collection performance. The maximum water collection efficiency of the prepared surface is measured up to 427.36 mg h-1 cm-2, which is 97% higher than that of the control sample. Furthermore, the surface can be folded into different forms to realize a flexible collector. We envision that our work provides a green fabrication strategy to construct a superwetting surface for highly efficient fog collection.
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Affiliation(s)
- Jinghui Gao
- College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, 498 South Shaoshan Street, Changsha 410004, China
| | - Yuxin Song
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Longhui Huang
- College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, 498 South Shaoshan Street, Changsha 410004, China
| | - Hong Luo
- College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, 498 South Shaoshan Street, Changsha 410004, China
| | - Xinran Dong
- College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, 498 South Shaoshan Street, Changsha 410004, China
| | - Cong Wang
- State Key Laboratory of Precision Manufacturing for Extreme Service Performance, College of Mechanical and Electrical Engineering, Central South University, 932 South Lushan Street, Changsha 410083, China
| | - Ji-An Duan
- State Key Laboratory of Precision Manufacturing for Extreme Service Performance, College of Mechanical and Electrical Engineering, Central South University, 932 South Lushan Street, Changsha 410083, China
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Sun P, Feng X, Tian G, Zhang X, Chu J. Ultrafast Self-Healing Superhydrophobic Surface for Underwater Drag Reduction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:10875-10885. [PMID: 36001007 DOI: 10.1021/acs.langmuir.2c01566] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The self-healing superhydrophobic surfaces have attracted great interest owing to restoring superhydrophobicity without preparation crafts. However, the self-healing superhydrophobic surface still faces the dilemma of long repairing time. Especially in aqueous environments, superhydrophobic surfaces are highly susceptible to contamination and damage. In the current study, a superhydrophobic surface with ultrafast repairability was developed, which apply for drag reduction in aqueous medium. The prepared superhydrophobic surface can recover superhydrophobicity in only 30 s after severe physical and chemical damage. In addition, this research pioneered the combination of superhydrophobicity and porous structures for underwater drag reduction. The study of drag reduction confirms that the superhydrophobic surface can reduce the frictional drag by about 43% in the water. However, the drag reduction rate of the superhydrophobic surface with the porous structure can be improved to 76% due to increased stability of the air layer. More importantly, the porous structure with the average pore size of 50 μm has the most excellent stability through further experiments on the underwater air layer. This is attributed to the proper size of the pore to effectively balance the capillary force and resist wetting in the marginal region. This study will bring inspiration for the large-scale application of superhydrophobic surfaces and long-term drag reduction.
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Affiliation(s)
- Pengfei Sun
- College of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, China
| | - Xiaoming Feng
- College of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, China
| | - Guizhong Tian
- College of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, China
| | - Xiaowei Zhang
- College of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, China
| | - Jiahui Chu
- College of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, China
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Tsao HK, Walker GC. Virtual Issue: Wettability Gradient Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:603-604. [PMID: 35038869 DOI: 10.1021/acs.langmuir.1c02940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
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Song YY, Yu ZP, Dong LM, Zhu ML, Ye ZC, Shi YJ, Liu Y. Cactus-Inspired Janus Membrane with a Conical Array of Wettability Gradient for Efficient Fog Collection. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:13703-13711. [PMID: 34767375 DOI: 10.1021/acs.langmuir.1c02368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Fog collection plays an important role in alleviating the global water shortage. Despite great progress in creating bionic surfaces to collect fog, water droplets still could adhere to the microscale hydrophilic region and reach the thermodynamic stable state before falling, which delays the transport of water and hinders the continuous fog collection. Inspired by lotus leaves and cactuses, we designed a Janus membrane that functions to both collect fog from the air and transport it to a certain region. The Janus membrane with opposite wettability contains conical microcolumns with a wettability gradient and hydrophilic copper mesh surface. The apexes of conical microcolumns are superhydrophobic and the rest are hydrophobic. The fog droplets were deposited, coalesced, and directionally transported to the bottom of the conical microcolumns. Then, the droplets unidirectionally passed through the membrane and flowed into the water film on the surface of the copper mesh. The asymmetric structural and wettability merits endow the Janus membrane with an improved fog collection of ∼7.05 g/cm2/h. The study is valuable for designing and developing fluid control equipment in fog collection, liquid manipulation, and microfluidics.
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Affiliation(s)
- Yun-Yun Song
- School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, P. R. China
| | - Zhao-Peng Yu
- School of Automotive Engineering, Changshu Institute of Technology, No. 99 Hushan Road, Changshu, Suzhou 215500, P. R. China
| | - Li-Ming Dong
- School of Automotive Engineering, Changshu Institute of Technology, No. 99 Hushan Road, Changshu, Suzhou 215500, P. R. China
| | - Mao-Lin Zhu
- School of Automotive Engineering, Changshu Institute of Technology, No. 99 Hushan Road, Changshu, Suzhou 215500, P. R. China
| | - Zhi-Chun Ye
- School of Automotive Engineering, Changshu Institute of Technology, No. 99 Hushan Road, Changshu, Suzhou 215500, P. R. China
| | - Yuan-Ji Shi
- Department of Mechanical Engineering, Nanjing Institute of Industry Technology, Nanjing 210046, Jiangsu, P. R. China
| | - Yan Liu
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022, P. R. China
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Liang X, Li D, Li S, Xu C, Guo Z. Artificial Leaf for Switchable Droplet Manipulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5745-5752. [PMID: 33929871 DOI: 10.1021/acs.langmuir.1c00799] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Droplet manipulation plays an important role in scientific research, daily life, and practical production such as biological and chemical analysis. Inspired by the structure and function of three typical leaf veins, the bionic texture was replicated by the template method, and the artificial leaf was selectively treated by nanoparticles to obtain a quasi-three-dimensional hybrid superhydrophobic-hydrophilic surface. When the droplet touches the surface of the leaf, it will be attracted to the bottom of the main vein from different directions even in horizontal conditions due to the Laplace pressure gradient and energy gradient. The simulation analysis demonstrates that the reason for directional transportation is the energy gradient of the droplets on the different levels of veins, including the thin veins, lateral veins, and main vein. Meanwhile, the experimental result of water collection also showed an outstanding directional transportation effect and excellent water collection efficiency. In addition, when the sample is tilted upside down, the droplet will flow back to the main vein along the lateral vein and then flow down the main vein, showing a good droplet pumping effect. Therefore, the directional and polydirectional transportation of droplets on the same sample is successfully realized, and the conversion between executing single and multiple tasks simultaneously can be realized only by upright and inverted samples. This work provided a new strategy for directional and polydirectional water manipulation, water collection, directional drainage, and microfluidic devices.
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Affiliation(s)
- Xiaojing Liang
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Deke Li
- School of Materials Engineering, Lanzhou Institute of Technology, Lanzhou 730050, People's Republic of China
| | - ShanPeng Li
- College of Engineering, Lishui University, Lishui 323000, People's Republic of China
| | - Chenggong Xu
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Zhiguang Guo
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan 430062, People's Republic of China
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