Evaporation-triggered directional transport of asymmetrically confined droplets

He, Xukun; Cheng, Jiangtao

doi:10.1016/j.jcis.2021.06.164

Cited by 4 publications

(2 citation statements)

References 54 publications

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“…Elsewhere, it has been shown with simulations that an isopressure droplet, in a wedge with hysteresis, has F capillary = 0. 48,56 For the present case, the analytical proof is straightfor-ward: F capillary with the three respective terms in explicit form (eq 2) is identically null for every H t , H b , ϑ t , ϑ b and β that satisfy eq 1 (see section S1, Supporting Information). The third term, F p , is obtained by substituting ΔP Laplace = 2σ lv /R t .…”

Section: Discussionmentioning

confidence: 82%

“…Regarding the droplet suspended in the conical pore with hysteresis, the contact angles ϑ t and ϑ b can vary in the range [ϑ r , ϑ a ]. By imposing the curvature radii R t (eq S1.1) and R b (eq S1.2) to be equal, we obtain eq , the relationship to be satisfied by the five parameters H t , H b , ϑ t , ϑ b , and β in order to have a uniform internal pressure (as for wedges ,− ). In eq we define the shape ratio λ ≡ H t / H b between the heights of the contact lines respect to the apex.…”

Section: Discussionmentioning

confidence: 99%

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Single Condensation Droplet Self-Ejection from Divergent Structures with Uniform Wettability

Di Novo,

Bagolini,

Pugno

2024

ACS Nano

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Coalescence-induced condensation droplet jumping has been extensively studied for anti-icing, condensation heat transfer, water harvesting, and self-cleaning. Another phenomenon that is gaining attention for potential enhancements is the self-ejection of individual droplets. However, the mechanism underlying this process remains elusive due to cases in which the abrupt detachment of an interface establishes an initial Laplace pressure difference. In this study, we investigate the self-ejection of individual droplets from uniformly hydrophobic microstructures with divergent geometries. We design, fabricate, and test arrays of truncated, nanostructured, and hydrophobic microcones arranged in a square pattern. High-speed microscopy reveals the dynamics of a single condensation droplet between four cones: after cycles of growth and stopped self-propulsion, the suspended droplet self-ejects without abrupt detachments. Through analytical modeling of the droplet in a conical pore as an approximation, we describe the slow isopressure growth phases and the rapid transients driven by surface energy release once a dynamic configuration is reached. Microcones with uniform wettability, in addition to being easier to fabricate, have the potential to enable the self-ejection of all nucleated droplets with a designed size, promising significant improvements in the aforementioned applications and others.

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Section: Discussionmentioning

confidence: 82%