Capillary Balancing: Designing Frost-Resistant Lubricant-Infused Surfaces

Wong, William S. Y.; Hegner, Katharina I.; Donadei, Valentina; Hauer, Lukas; Naga, Abhinav; Vollmer, Doris

doi:10.1021/acs.nanolett.0c02956

Cited by 49 publications

(56 citation statements)

References 34 publications

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“…Nanoscopic anti-icing surfaces developed to address the icing challenge aim to tune the water-ice transformation at a few nanometer scales. These include nanostructured surfaces [18][19][20] , slippery liquid-infused porous surfaces 21,22 , magnetic slippery surfaces 23 , and even anti-frosting [24][25][26][27][28] surfaces. Furthermore, confinement effects could drastically affect the phase-change phenomenon in membrane 29 , porous material [30][31][32][33] , nanochannels 34,35 , and carbon nanotubes 36,37 .…”

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confidence: 99%

Freezing of few nanometers water droplets

et al. 2021

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Water-ice transformation of few nm nanodroplets plays a critical role in nature including climate change, microphysics of clouds, survival mechanism of animals in cold environments, and a broad spectrum of technologies. In most of these scenarios, water-ice transformation occurs in a heterogenous mode where nanodroplets are in contact with another medium. Despite computational efforts, experimental probing of this transformation at few nm scales remains unresolved. Here, we report direct probing of water-ice transformation down to 2 nm scale and the length-scale dependence of transformation temperature through two independent metrologies. The transformation temperature shows a sharp length dependence in nanodroplets smaller than 10 nm and for 2 nm droplet, this temperature falls below the homogenous bulk nucleation limit. Contrary to nucleation on curved rigid solid surfaces, ice formation on soft interfaces (omnipresent in nature) can deform the interface leading to suppression of ice nucleation. For soft interfaces, ice nucleation temperature depends on surface modulus. Considering the interfacial deformation, the findings are in good agreement with predictions of classical nucleation theory. This understanding contributes to a greater knowledge of natural phenomena and rational design of anti-icing systems for aviation, wind energy and infrastructures and even cryopreservation systems.

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confidence: 99%

Freezing of few nanometers water droplets

et al. 2021

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“…Notably, even condensation of water vapor from a near-field water source (immersion) into the superhydrophobic layer can trigger a premature effervescence reaction. The stability of bulk GL material at different humidities is analyzed using a climate chamber [37,40] (exposure time: 30 min). The exposure time of 30 min exceeds the preparation time for the PVP-GL layer (typically 10-20 min).…”

Section: Scale-up Design (From Model Surface To Quad-layered Coatings)mentioning

confidence: 99%

Effervescence‐Inspired Self‐Healing Plastrons for Long‐Term Immersion Stability

Wong

Vollmer

2021

Adv Funct Materials

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The use of superhydrophobic/superamphiphobic surfaces demands the presence of a stable plastron, i.e., a film of air between micro-and nanostructures. Without actively replenishing the plastron with gases, it eventually disappears during immersion. The air diffuses into the immersion liquid, i.e., water. Current methods for sustaining the plastron under immersion remain limited to techniques such as electrocatalysis, electrolysis, boiling, and airrefilling. These methods are difficult to implement at scale, are either energyconsuming, or require continuous monitoring of the plastron (and subsequent intervention). Here, the concept of passive on-demand recovery of the plastron via the use of a chemical reaction (effervescence) is presented. A superhydrophobic nanostructured surface is layered onto a wetting-reactive, gas-forming (effervescent) sublayer. During extended exposure to moisture, the effervescent layer must be protected by a moisture-absorbent, water-soluble polymer. Under prolonged immersion, partial collapse of the Cassie-state induces contact of water with the effervescent layer. This induces the local formation of gases from effervescence, which restores the Cassie-state. These facile and scalable design principles offer a new route toward intervention-free and immersion-durable superhydrophobic/superamphiphobic surfaces.

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“…For example, loss of lubricant during frost formation over lubricated surfaces was lowest for substrates with the smallest interstitial space. 20 Enhanced capillary effects generated by nanoscale roughness or hierarchical features also improve the lubricant retention during frost formation 21 and condensation. 22 Within the extensive field of porous materials, there are other applications that require keeping an immobilized liquid on a surface.…”

Section: Introductionmentioning

confidence: 99%

Materials with Hierarchical Porosity Enhance the Stability of Infused Ionic Liquid Films

et al. 2021

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Defined surface functionalities can control the properties of a material. The layer-by-layer method is an experimentally simple yet very versatile method to coat a surface with nanoscale precision. The method is widely used to either control the chemical properties of the surface via the introduction of functional moieties bound to the polymer or create nanoscale surface topographies if one polymeric species is replaced by a colloidal dispersion. Such roughness can enhance the stability of a liquid film on top of the surface by capillary adhesion. Here, we investigate whether a similar effect allows an increased retention of liquid films within a porous surface and thus potentially increases the stability of ionic liquid films infused within a porous matrix in the supported ionic liquid-phase catalysis. The complex geometry of the porous material, long diffusion pathways, and small sizes of necks connecting individual pores all contribute to difficulties to reliably coat the required porous materials. We optimize the coating process to ensure uniform surface functionalization via two steps. Diffusion limitations are overcome by force-wetting the pores, which transports the functional species convectively into the materials. Electrostatic repulsion, which can limit pore accessibility, is mitigated by the addition of electrolytes to screen charges. We introduce nanoscale topography in microscale porous SiC monoliths to enhance the retention of an ionic liquid film. We use γ-Al 2 O 3 to coat monoliths and test the retention of 1-butyl-2,3-dimethylimidazolium chloride under exposure to a continuous gas stream, a setup commonly used in the water-gas shift reaction. Our study showcases that a hierarchical topography can improve the stability of impregnated ionic liquid films, with a potential advantage of improved supported ionic liquid-phase catalysis.

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Capillary Balancing: Designing Frost-Resistant Lubricant-Infused Surfaces

Cited by 49 publications

References 34 publications

Freezing of few nanometers water droplets

Freezing of few nanometers water droplets

Effervescence‐Inspired Self‐Healing Plastrons for Long‐Term Immersion Stability

Materials with Hierarchical Porosity Enhance the Stability of Infused Ionic Liquid Films

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