Unique ice dendrite morphology on state-of-the-art oil-impregnated surfaces

Abstract

Due to its multifaceted impact in various applications, icing and ice dendrite growth has been the focus of numerous studies in the past. Dendrites on wetting (hydrophilic) and nonwetting (hydrophobic) surfaces are sharp, pointy, branching, and hairy. Here, we show a unique dendrite morphology on state-of-the-art micro/nanostructured oil-impregnated surfaces, which are commonly referred to as slippery liquid-infused porous surfaces or liquid-infused surfaces. Unlike the dendrites on traditional textured hydrophilic and hydrophobic surfaces, the dendrites on oil-impregnated surfaces are thick and lumpy without pattern. Our experiments show that the unique ice dendrite morphology on lubricant-infused surfaces is due to oil wicking into the porous dendritic network because of the capillary pressure imbalance between the surface texture and the dendrites. We characterized the shape complexity of the ice dendrites using fractal analysis. Experiments show that ice dendrites on textured oil-impregnated surfaces have lower fractal dimensions than those on traditional lotus leaf-inspired air-filled porous structures. Furthermore, we developed a regime map that can be used as a design guideline for micro/nanostructured oil-impregnated surfaces by capturing the complex effects of oil chemistry, oil viscosity, and wetting ridge volume on dendrite growth and morphology. The insights gained from this work inform strategies to reduce lubricant depletion, a major bottleneck for the transition of micro/nanostructured oil-impregnated surfaces from bench-top laboratory prototypes to industrial use. This work will assist the development of next-generation depletion-resistant lubricant-infused ice-repellent surfaces.

Apple-like Shape of Freezing Paraffin Wax Droplets and Its Origin

“…The sharp tip registered during the cooling of water droplets exhibits a remarkable universality in its shape, independent of the cooling regime and physical properties of the substrate [ 4 , 5 , 6 , 7 , 8 , 9 ], which has been attributed to the jump in water density during freezing. Dendrite-like morphology has recently been observed on the outer shell of oil-coated frozen droplets [ 10 ]. The shape of the solidified wax droplets was studied intensively in view of their applications in 3D solid-inkjet printing [ 11 , 12 ].…”

Visualization and Experimental Characterization of Wrapping Layer Using Planar Laser-Induced Fluorescence

“…Chemically modified and functionalized surfaces with roughness possess nonwetting properties , that are beneficial for a wide range of industrial applications, including antifouling, − anti-icing, − drag reduction, − and phase change. − The central theme of nonwettability relies heavily on suppressing contact between the solid substrate and the liquid droplet using an air cushion trapped within the surface texture. , State-of-the-art approaches have been based on the “lotus” effect, where intricate nanostructures are carefully designed to maintain an air layer between the structures, forming a stable interface between the substrate and the applied liquid. , The pockets of air trapped beneath the droplets placed on these surfaces lead to a composite solid–liquid–air interface in thermodynamic equilibrium. As long as the air pockets within the nanostructures remain stable (for example, by heating the surface above the boiling point), the surface continues to exhibit superior liquid repellency.…”