Self-propelled drop jumping during defrosting and drainage characteristic of frost melt water from inclined superhydrophobic surface

Liu, Dong; Qian, Chenlu; Gao, Shangwen; Zhao, Xiangen; Zhou, Yiming

doi:10.1016/j.ijrefrig.2017.04.022

Cited by 32 publications

(14 citation statements)

References 30 publications

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“…Chen et al observed that the frost meltwater exhibited a relatively low fracture density and became a large spherical water droplet at the end of defrosting on horizontal nanograssed superhydrophobic surfaces . The self-propelled behavior of melting droplets during defrosting was also reported, ,, and many research studies have confirmed the excellent meltwater drainage performance on superhydrophobic surfaces. − However, some fundamental issues are still unclear. For example, how does the meltwater film dewet into a spherical droplet?…”

Section: Introductionmentioning

confidence: 99%

Meltwater Evolution during Defrosting on Superhydrophobic Surfaces

Chu

Wang

2017

ACS Appl. Mater. Interfaces

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Defrosting is essential for removing frost from engineering surfaces, but some fundamental issues are still unclear, especially for defrosting on superhydrophobic surfaces. Here, defrosting experiments on prepared superhydrophobic surfaces were conducted along with the investigation on meltwater evolution characteristics. According to the experiments, the typical meltwater evolution process on superhydrophobic surfaces can be divided into two stages: dewetting by edge curling and dewetting by shrinkage. The edge curling of a meltwater film is a distinct phenomenon and has been first reported in this work. Profiting from the ultralow adhesion of the superhydrophobic surface, edge curling is mainly attributed to two unbalanced forces (one at the interface between the ice slurry layer and pure water layer and the other in the triple phase line area) acting on the layered meltwater film. During the multi-meltwater evolution process, the nonbreaking of chained droplets on superhydrophobic surfaces is also an interesting phenomenon, which is controlled by the interaction between the surface tension and the retentive force because of contact angle hysteresis. An approximate criterion was then developed to explain and determine the status of chained droplets, and experimental data from various surfaces have validated the effectiveness of this criterion. This work may deepen the understanding of defrosting on superhydrophobic surfaces and promote antifrosting/icing applications in engineering.

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Section: Introductionmentioning

confidence: 99%

Meltwater Evolution during Defrosting on Superhydrophobic Surfaces

Chu

Wang

2017

ACS Appl. Mater. Interfaces

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“…As reported in literature which contains our own work, large amounts of surface energy can be released during the shrinking of melting frost with irregular shape, which easily triggers a self-propelled movement such as jumping. [22][23][24] As seen in Fig.3(a), the self-propelled jumping of melting frost indeed occurs very frequently (the solid circles represent original frost, the dashed circles show clean surfaces after jumping, and the white arrows indicate shadows of jumping paths). These jumping movements are able to selfremove most frost pieces, leaving an almost clean surface.…”

Section: Frost Jump Off During Defrosting When Frost Quantity Is Littlementioning

confidence: 76%

“…[18][19] Like that occurred during condensation, [20][21] self-propelled jumping, rotating and sliding movements during defrosting also take place frequently, making the defrosting process very dynamic and generating very low surface coverages on superhydrophobic surfaces. [22][23][24] On vertical superhydrophobic surfaces, the defrosting process is more efficient that the melting frost departs from the superhydrophobic surface directly at the early stage of defrosting. [25][26][27] Compared with conventional surfaces such as bare Aluminum surfaces and hydrophobic surfaces, the retention water mass or fraction presents a much lower value.…”

Section: Indroductionmentioning

confidence: 99%

Frost Self-Removal Mechanism during Defrosting on Vertical Superhydrophobic Surfaces: Peeling Off or Jumping Off

Chu

Wen

2018

Langmuir

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Although a superhydrophobic surface has potentials to delay frosting, it fails finally when conditions are too harsh, so defrosting is still essential. Here, we investigated the frost self-removal mechanism during defrosting on vertical superhydrophobic surfaces. Owing to the great water repellency of the superhydrophobic surface and the water absorption of porous frost, meltwater close to the surface tends to permeate into the frost layer. As frost density is much less than water density, the frost volume shrinks during defrosting. When the frost quantity is large, the permeation effect dominates because there is much porous frost. The permeation effect separates the unmelted frost layer from the superhydrophobic surface, as a result, the frost peels off by gravity completely. When the frost quantity is little, the permeation effect is negligible, while the volume shrinkage effect works, making the thin frost layer break up into many small pieces. These small frost pieces keep irregular shapes and continue to shrink, releasing large amounts of surface energy to drive themselves jump off from the superhydrophobic surface. However, compared with the peeling off mode, the jumping off mode is not so effective that there are still small droplets adhering on the surface after defrosting. This work may provide guides for defrosting application of superhydrophobic surfaces in related engineering fields.

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“…Here, E k0 obtained by the coalescence of two droplets can be expressed as: 60 E k0 = E s − E vis − E w …”

Section: Resultsmentioning

confidence: 99%

Beetle-like droplet-jumping superamphiphobic coatings for enhancing fog collection of sheet arrays

Wang

Zeng

et al. 2020

RSC Adv.

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Self-propelled drop jumping during defrosting and drainage characteristic of frost melt water from inclined superhydrophobic surface

Cited by 32 publications

References 30 publications

Meltwater Evolution during Defrosting on Superhydrophobic Surfaces

Meltwater Evolution during Defrosting on Superhydrophobic Surfaces

Frost Self-Removal Mechanism during Defrosting on Vertical Superhydrophobic Surfaces: Peeling Off or Jumping Off

Beetle-like droplet-jumping superamphiphobic coatings for enhancing fog collection of sheet arrays

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