| DONG Jian,DONG He,LONG Zhi-jian,GUO You-hai,YE Sen-bin.Effect of Micro/Nano Structure on Condensation Characteristics of Hierarchical Superhydrophobic Silicon Surface[J],48(9):104-112 |
| Effect of Micro/Nano Structure on Condensation Characteristics of Hierarchical Superhydrophobic Silicon Surface |
| Received:January 17, 2019 Revised:September 20, 2019 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2019.09.010 |
| KeyWord:micro-nano hierarchical structure superhydrophobic silicon surface condensate droplets spontaneous migration water collection efficiency |
| Author | Institution |
| DONG Jian |
Zhejiang University of Technology, Hangzhou , China |
| DONG He |
Zhejiang University of Technology, Hangzhou , China |
| LONG Zhi-jian |
Zhejiang University of Technology, Hangzhou , China |
| GUO You-hai |
Zhejiang University of Technology, Hangzhou , China |
| YE Sen-bin |
Zhejiang University of Technology, Hangzhou , China |
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| Abstract: |
| The work aims to study the influence of microstructure center distance on heat transfer performance of micro- nano hierarchical superhydrophobic silicon surface. The wet etching was applied to construct micro-nano pyramid structures with center distance of 22, 24, 26, 28 and 30 μm on the silicon surface and then sol-gel method was used to coat hydrophobic nano silica particles to obtain micro-nano hierarchical superhydrophobic surface. The wettability and microtopography characteristics of the superhydrophobic silicon surface were analyzed by contact angle meter and scanning electron microscope. Spontaneous migration of small condensate droplets was observed by optical microscope. The electronic balance was used to measure the mass of the collected condensation water. For the same nanostructure, with the increase of microstructure center distance, the static contact angle of droplets became smaller, the spontaneous migration of small condensate droplets became slower and the average water collection efficiency decreased within the same period. Flooding was observed when relative humidity was larger than 90%. The water collection efficiency of the micro-nano structured hierarchical superhydrophobic silicon surface (22 μm micro-distance) was 1.38 times as large as that of the monolayer microstructure Si surface, 1.27 times as large as that of the monolayer nanostructure hydrophobic surface, 1.75 times as large as that of the hydrophobic smooth Si surface and 3.6 times as large as that of the hydrophilic smooth SiO2 surface. For the same nanostructure, reducing the microstructure spacing is helpful to enhance the surface heat exchange efficiency of hierarchical superhydrophobic silicon surface. |
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