Superhydrophobic behavior of cylinder dual-scale hierarchical nanostructured surfaces

Sui, Xin; Wang, Yubo; Sun, Yongyang; Liang, Wenyan; Xue, Yiqing; Bonsu, Alex Osei

doi:10.1016/j.colsurfa.2021.127406

Cited by 9 publications

(9 citation statements)

References 40 publications

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“…These findings also prove that superhydrophobicity is largely dependent on multi-scale structures as seen in nature such as lotus leaves ( Darmanin and Guittard, 2015 ; Neinhuis and Barthlott, 1997 ). Besides, the results are in concordance with literature; MN structured surfaces were shown both experimentally and theoretically that the presence of submicron and nanostructures can decrease the threshold of micropillar height to attain superhydrophobicity ( Patankar, 2004 ; Sui et al, 2021 ). In cases of extremely small droplets, the nanostructures can prevent them from accessing the groves ( Liu et al, 2011 ).…”

Section: Resultssupporting

confidence: 90%

Bio-Inspired Hierarchical Micro/Nanostructured Surfaces for Superhydrophobic and Anti-Ice Applications

Zhang

Uzoma

Xiaoyang

et al. 2022

Front. Bioeng. Biotechnol.

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We report a scalable and cost-effective fabrication approach for constructing bio-inspired micro/nanostructured surfaces. It involves silicon microstructure etching using a deep reactive ion etch (DRIE) method, nanowires deposition via glancing angle deposition (GLAD) process, and fluorocarbon thin film deposition. Compared with the smooth, microstructured, and nanostructured surfaces, the hierarchical micro/nanostructured surfaces obtained via this method showed the highest water contact angle of ∼161° and a low sliding angle of <10°. It also offered long ice delay times of 2313 s and 1658 s at −5°C and −10°C respectively, more than 10 times longer than smooth surfaces indicating excellent anti-icing properties and offering promising applications in low-temperature environments. These analyses further proved that the surface structures have a significant influence on surface wettability and anti-icing behavior. Hence, the GLAD process which is versatile and cost-effective offers the freedom of constructing nanostructures on top of microstructures to achieve the required objective in the fabrication of micro/nanostructured surfaces when compared to other fabrication techniques.

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Section: Resultssupporting

confidence: 90%

Bio-Inspired Hierarchical Micro/Nanostructured Surfaces for Superhydrophobic and Anti-Ice Applications

Zhang

Uzoma

Xiaoyang

et al. 2022

Front. Bioeng. Biotechnol.

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“…During droplet retreat, Young’s equation is locally valid as follows where γ la , γ sa , and γ ls are the interfacial tension between the liquid–gas, solid-gas, and solid–liquid interfaces, respectively. The change in surface energy when the droplet recedes at different positions can be described as follows The adhesion energy consumed by detaching from the microstructure unit length during droplet retreat is given as follows When the droplets reached maximum spreading, the number of nanorods touching at the three structural scales are denoted as n 1 , n 2 , and n 3 , respectively. − The adhesion energy consumed during the droplet rebound process is respectively given below The initial kinetic energy of the droplet at the moment of falling on the surface of different scales is the same as the surface energy. The surface energy of the droplet after rebounding to the highest height is the same as the initial surface energy, and the initial kinetic energy is converted into potential energy, adhesion loss energy, and potential energy for microstructural deformation after rebound.…”

Section: Resultsmentioning

confidence: 99%

Dynamic Anti-Icing Performance of Flexible Hybrid Superhydropohobic Surfaces

Hou,

Zhan,

Fan

et al. 2023

ACS Appl. Mater. Interfaces

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Normal superhydrophobic surfaces with a rough topography provide pocketed air at the solid−liquid interface, which guides the droplet to easily detach from the surface at room temperature. However, at low temperatures, this function attenuates obviously. In this research, a flexible hybrid topography with submillimeter (sub-mm) and microcone arrays is designed to adjust the impacting behavior of the droplet. The sub-mm cone could provide rigid support to limit deformation, leading to reduced energy consumption during impact processes. However, the microcone could maintain surface superhydrophobicity under different conditions, preventing droplet breakage and the change of the droplet contact state during impact processes by providing multiple contact points. Under the synergistic effect, such a hybrid structure could provide much more pocket air at the solid−liquid interface to limit the spreading of liquid droplets and reduce the energy loss during the impact process. At a low temperature (−5 °C), even if the impact height is reduced to 1 cm, the droplets still could be bound off, and the hybrid superhydrophobic surface presents excellent dynamic anti-icing ability. The special flexible hybrid superhydropohobic surface has potential application in fast self-cleaning and anti-icing fields.

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“…A large number of thermodynamic studies have been conducted to analyze the C‐W transformation mechanism. This ranges from analyzing simple 2D models [ 43 ] to more complex three‐dimensional models, [ 44 ] along with simulations and assessments of single, uniformly distributed arrays and complex, diverse microstructurally arranged surfaces. Moreover, it extends from general thermodynamic analyses to the exploration of specific model simulations.…”

Section: Fundamental Understanding Of Superhydrophobicitymentioning

confidence: 99%

“…The most commonly used method for thermodynamic simulation of the wetting transition is finite element analysis. [ 44 , 51 ] The entire composite system is broken down into a multitude of small, simple units that interact with one another, and the small units are analyzed energetically. The motion environment is simplified, and the energy of all the small units is integrated to deduce the energy variation of the whole system.…”

Section: Fundamental Understanding Of Superhydrophobicitymentioning

confidence: 99%

“…For the energy analysis of the W state and C state, the W state has a relatively low free energy state, while the C state has a relatively high free energy state. [ 44a ] This indicates that the W state is more stable from a free energy minimization perspective, while the C state is thermodynamically unstable. However, in the actual experiment, the C state will not suddenly transform into the W state without any external influence.…”

Section: Fundamental Understanding Of Superhydrophobicitymentioning

confidence: 99%

See 1 more Smart Citation

The Challenge of Superhydrophobicity: Environmentally Facilitated Cassie–Wenzel Transitions and Structural Design

Zhong,

Xie,

Guo

2023

Advanced Science

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Superhydrophobic materials can be used in various fields to optimize production and life due to their unique surface wetting properties. However, under certain pressure and perturbation conditions, the droplets deposited on superhydrophobic materials are prone to change from Cassie state to Wenzel state, which limits the practical applications of the materials. In recent years, a large number of works have investigated the transition behavior, transition mechanism, and influencing factors of the wetting transition that occurs when a superhydrophobic surface is under a series of external environments. Based on these works, in this paper, the phenomenon and kinetic behavior of the destruction of the Cassie state and the mechanism of the wetting transition are systematically summarized under external conditions that promote the wetting transition on the material surface, including pressure, impact, evaporation, vibration, and electric wetting. In addition, superhydrophobic surface morphology has been shown to directly affect the duration of the Cassie state. Based on the published work the effects of specific morphology on the Cassie state, including structural size, structural shape, and structural level, are summarized in this paper from theoretical analyses and experimental data.

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Superhydrophobic behavior of cylinder dual-scale hierarchical nanostructured surfaces

Cited by 9 publications

References 40 publications

Bio-Inspired Hierarchical Micro/Nanostructured Surfaces for Superhydrophobic and Anti-Ice Applications

Bio-Inspired Hierarchical Micro/Nanostructured Surfaces for Superhydrophobic and Anti-Ice Applications

Dynamic Anti-Icing Performance of Flexible Hybrid Superhydropohobic Surfaces

The Challenge of Superhydrophobicity: Environmentally Facilitated Cassie–Wenzel Transitions and Structural Design

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