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In this letter, we introduce a novel liquid manipulation strategy to design dynamically hydrophobic and statically hydrophobic/hydrophilic patterned surfaces using an "omniphobicity"-based technique. The surfaces guide the sliding direction of a droplet in the presence of a statically hydrophilic area where the droplet does not stick on the transport path significantly enhancing the fluidic system transport efficiency. The concept of dynamically hydrophobic and statically hydrophobic/hydrophilic patterned surfaces in conjunction with omniphobic patterning techniques having surface multifunctionality, we believe, has potential not only for fluidic applications but also for future material engineering development.

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.

As frost formation and ice accumulation result in serious problems in various industrial systems, some anti-icing system is highly required, and passive anti-icing processes based on ice prevention coatings have attracted much attention. Recently, antifreeze liquid-infused surfaces (LISs) have been developed for the preparation of ice-phobic surfaces owing to their low ice adhesion strength and antifrosting properties. However, it is still challenging to add an optical function such as high transparency to antifreeze LISs despite the potential for the application in window coatings. In addition, the influence on anti-icing properties by the thickness of antifreeze liquid layer and base layer are still unclear. Here, we designed highly transparent coating surfaces that were resistant to ice adhesion and frost formation. We controlled the thickness, surface roughness, and refractive index of the base layer through a spray layer-by-layer (LbL) method and then investigated the effect on the optical properties, ice adhesion strength, and frost formation behavior. The frost-resisting properties of the surfaces were clearly improved with the increase of the lubricant thickness as well as the increase of the number of bilayers; the parallel transmittance of antifreeze LIS composed of ethylene glycol and this base layer was approximately 92.6%, and the ice adhesion strength was below 17 kPa regardless of the number of bilayers. These results indicated that a high lubricant thickness coating can achieve both excellent anti-icing properties and transparency; the antifreeze LIS based on a 100 bilayer base coating had excellent antifrosting properties owing to its thick antifreeze liquid layer and maintained both of high transparency and low ice adhesion. Furthermore, the spray LbL method makes it possible to fabricate the base layer in short time and also in large scale, which is quite useful for the practical application of antifreeze LIS. This work will be of enormous help for the design of transparent anti-icing coatings as well as industrial applications such as solar cells and the windows of transportation vehicles.

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