Liquid-Infused Smooth Surface for Improved Condensation Heat Transfer

Abstract

Control of vapor condensation properties is a promising approach to manage a crucial part of energy infrastructure conditions. Heat transfer by vapor condensation on superhydrophobic coatings has garnered attention, because dropwise condensation on superhydrophobic surfaces with rough structures leads to favorable heat-transfer performance. However, pinned condensed water droplets within the rough structure and a high thermodynamic energy barrier for nucleation of superhydrophobic surfaces limit their heat-transfer increase. Recently, slippery liquid-infused surfaces (SLIPS) have been investigated, because of their high water sliding ability and surface smoothness originating from the liquid layer. However, even on SLIPS, condensed water droplets are eventually pinned to degrade their heat-transfer properties after extended use, because the rough base layer is exposed as infused liquid is lost. Herein, we report a liquid-infused smooth surface named "SPLASH" (surface with π electron interaction liquid adsorption, smoothness, and hydrophobicity) to overcome the problems derived from the rough structures in previous approaches to obtain stable, high heat-transfer performance. The SPLASH displayed a maximum condensation heat-transfer coefficient that was 175% higher than that of an uncoated substrate. The SPLASH also showed higher heat-transfer performance and more stable dropwise condensation than superhydrophobic surfaces and SLIPS from the viewpoints of condensed water droplet mobility and the thermodynamic energy barrier for nucleation. The effects of liquid-infused surface roughness and liquid viscosity on condensation heat transfer were investigated to compare heat-transfer performance. This research will aid industrial applications using vapor condensation.

Implementing Superhydrophobic Surfaces within Various Condensation Environments: A Review

“…reported a liquid‐infused smooth surface called “SPLASH” (surface with π‐electron interaction liquid adsorption, smoothness, and hydrophobicity). [ 59 ] The SPLASH was prepared on a copper plate, using silicone oil as the lubricating liquid. The effects of surface roughness and liquid viscosity were investigated.…”

Review of Micro–Nanoscale Surface Coatings Application for Sustaining Dropwise Condensation

“…The liquid entrainment problem has been handled by liquid infusion, and these surfaces are termed as slippery liquid infused porous surfaces (SLIPS) [165]. The disadvantage of SLIPS are their durability; after a certain time, liquid infusion diminishes, and due to condensate pinning, htc decreases [166]. Attempts have been made to develop microporous surfaces along with SAMs [167,168].…”

Mechanically durable and long-term repairable flexible lubricant-infused monomer for enhancing water collection efficiency by manipulating droplet coalescence and sliding

“…However, compared to superhydrophobic surfaces and hydrophobic/hydrophilic surfaces, FLIM surfaces have better water collection capacity due to their excellent heat transfer efficiency and low nucleation energy, which has been proved in previous reports. 36,37 Because the thickness of the infused lubricant decreases with time, the rough base layer is exposed and the water sliding ability cannot exist for a long period. In addition, on a rigid substrate, the droplets are easily blown away by natural wind.…”