A comparative study of droplet impact dynamics on a dual-scaled superhydrophobic surface and lotus leaf

Chen, Longquan; Xiao, Zhiyong; Chan, P.C.H.; Lee, Yi-Kuen; Li, Zhigang

doi:10.1016/j.apsusc.2011.04.094

Cited by 176 publications

(172 citation statements)

References 37 publications

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“…[10][11][12][13][14] Artificial superhydrophobic surfaces (SHSs) with contact angles larger than 150°are extremely low-energy surfaces that facilitate rapid drop bounce off due to the low friction between the drop and the substrate. [15][16][17][18][19][20][21][22][23] The drops retain a circular symmetry during the first inertial-driven spreading stage and the second capillary-controlled recoiling phase. In addition, the contact time (τ o ⩾ 2.2 rR 3 =g ð Þ 1=2 ) is independent of the impact speed.…”

Section: Introductionmentioning

confidence: 99%

Reducing the contact time using macro anisotropic superhydrophobic surfaces — effect of parallel wire spacing on the drop impact

Song

Liu

et al. 2017

NPG Asia Mater

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Surfaces designed to reduce the contact time of impacting droplets are potentially of great importance for fundamental science and technological applications, for example, anti-icing, self-cleaning and heating transfer applications. Previous studies have shown that the contact time can be reduced via introducing one or several crossing macroscale wires on superhydrophobic surfaces (SHSs). However, the impacts that strike far from the wires (off-center impacts) have contact times that are equal to those obtained on SHSs. Here we demonstrate that this problem can be largely solved by using macro anisotropic SHSs (macroaniso-SHSs)-in which the wires are parallel and macroscaled. The droplet contact time depends on the spacing between the macrostripes and is remarkably reduced by 40-50% when the spacing is comparable to the droplet size. Obvious differences in the contact time are not observed for impacts that are centered on the stripe and in the groove. The impacts centered in the groove produce new hydrodynamics that are characterized by extended spreading, easy break up and bouncing in a flying-eagle configuration. The study discusses the underlying mechanisms of the impact processes. Moreover, the effect of parallel wires on the contact time is discussed by comparing the droplet impact data for grooved rice leaves and non-grooved cabbage leaves. The enhanced drop mobility associated with the macro-aniso-SHSs should be very useful in many industrial applications.

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Section: Introductionmentioning

confidence: 99%

Reducing the contact time using macro anisotropic superhydrophobic surfaces — effect of parallel wire spacing on the drop impact

Song

Liu

et al. 2017

NPG Asia Mater

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“…This We 0 approximation is in fact similar to that observed on a CNT-coated micropatterned silicon surface where it was found that We 0 = 0.1. 15 It has been hypothesised that partial pinning phenomenon in the high We regime occurs when the Laplace pressure (P L ) of the deformed liquid-vapor interface is higher than the dynamic pressure (P D ) of the impinging water droplet, but at the same time smaller than the effective water hammer pressure (P WH ) of the impinging water droplet P WH > P L > P D . 26-27 \ 15, 28 The…”

mentioning

confidence: 99%

Physicochemical Characteristics and Droplet Impact Dynamics of Superhydrophobic Carbon Nanotube Arrays

Aria

Gharib

2014

Langmuir

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The physicochemical and droplet impact dynamics of superhydrophobic carbon nanotube arrays are investigated. These superhydrophobic arrays are fabricated simply by exposing the as-grown carbon nanotube arrays to a vacuum annealing treatment at a moderate temperature. This treatment, which allows a significant removal of oxygen adsorbates, leads to a dramatic change in wettability of the arrays, from mildly hydrophobic to superhydrophobic. Such change in wettability is also accompanied by a substantial change in surface charge and electrochemical properties. Here, the droplet impact dynamics are characterized in terms of critical Weber number, coefficient of restitution, spreading factor, and contact time. Based on these characteristics, it is found that superhydrophobic carbon nanotube arrays are among the best water-repellent surfaces ever reported. The results presented herein may pave a way for the utilization of superhydrophobic carbon nanotube arrays in numerous industrial and practical applications, including inkjet printing, direct injection engines, steam turbines, and microelectronic fabrication.

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“…This is something connected with contact angle hysteresis [9][10][11], in which the contact angle can vary within a range without moving of contact line, i.e. the contact line is pinned on the edge of the pillars [10][11][12] Generally speaking, the contact angle hysteresis (or roll-off angle), Â H , can be obtained by a simple experiment [10,15] (see Fig. 1c): if liquid is steadily added or removed from a droplet by a syringe, initially the contact line keeps static and the contact angle increases or decreases.…”

Section: Introductionmentioning

confidence: 99%

Droplets impact on textured surfaces: Mesoscopic simulation of spreading dynamics

Wang

Chen

2015

Applied Surface Science

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A comparative study of droplet impact dynamics on a dual-scaled superhydrophobic surface and lotus leaf

Cited by 176 publications

References 37 publications

Reducing the contact time using macro anisotropic superhydrophobic surfaces — effect of parallel wire spacing on the drop impact

Reducing the contact time using macro anisotropic superhydrophobic surfaces — effect of parallel wire spacing on the drop impact

Physicochemical Characteristics and Droplet Impact Dynamics of Superhydrophobic Carbon Nanotube Arrays

Droplets impact on textured surfaces: Mesoscopic simulation of spreading dynamics

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