How droplets nucleate and grow on liquids and liquid impregnated surfaces

Abstract

Condensation on liquids has been studied extensively in context of breath figure templating, materials synthesis and enhancing heat transfer using liquid impregnated surfaces. However, the mechanics of nucleation and growth on liquids remains unclear, especially on liquids that spread on the condensate. By examining the energy barriers of nucleation, we provide a framework to choose liquids that can lead to enhanced nucleation. We show that due to limits of vapor sorption within a liquid, nucleation is most favoured at the liquid-air interface and demonstrate that on spreading liquids, droplet submergence within the liquid occurs thereafter. We provide a direct visualization of the thin liquid profile that cloaks the condensed droplet on a liquid impregnated surface and elucidate the vapour transport mechanism in the liquid films. Finally, we show that although the viscosity of the liquid does not affect droplet nucleation, it plays a crucial role in droplet growth.

Porous polyurethane film fabricated via the breath figure approach for sustained drug release

“…The submerging of the droplets caused an increase in the distance among the pores. Also, there were several factors influencing droplet growth; these included the droplet density in the atmosphere of the system and the temperature of the surface . The submerging phenomenon was also seen at the cross‐section in the SEM images [Figure (A,B)].…”

Inverted Leidenfrost-like Effect during Condensation

“…During the entire droplet growth process, heat is continuously released to the substrate. For a single, isolated drop, the water vapor profile around the drop surface is radially symmetric and the drop radius follows 32,38 = R kt x (4) with x = 1/2. Our measurements show that the droplet growth profile on the cyclohexane surface roughly fits this growth curve ( Figure 3).…”

Fabrication of super slippery sheet-layered and porous anodic aluminium oxide surfaces and its anticorrosion property

“…However, most surface morphologies on the substrates result from retextured structures, and the slippery property is performed after immersing in the lubricating liquid. It is difficult for these surfaces to store lubricating oil [47,48]; in other words, they lose their super slippery characteristics after a few days due to a gravity effect when the samples come into contact with air or they move [49][50][51]. However, maintaining slippery quality for a long time is still a pressing challenge for the provision of super slippery surfaces with excellent anticorrosion property.…”