Using Frost to Promote Cassie Ice on Hydrophilic Pillars
Hyunggon Park, S. Farzad Ahmadi, Jonathan B. Boreyko
Abstract
We develop a novel approach to suspend ice in the air-trapping Cassie state without requiring any fragile hydrophobic coatings or nanostructures. First, frost was preferentially grown on the tops of hydrophilic aluminum pillars due to their sharp corners and elevation over the noncondensable gas barrier. Subsequently, Cassie ice was formed by virtue of the impacting droplets getting arrested by the upper frost tips. A scaling model reveals that the dynamic pressure of an impacting droplet causes the water to wick inside the porous frost faster than the timescale to impale between the pillars.
Topics & Concepts
Frost (temperature)Materials sciencePorosityScalingNanotechnologyComposite materialChemical physicsChemistryGeometryMathematicsSurface Modification and SuperhydrophobicityIcing and De-icing TechnologiesFluid Dynamics and Heat Transfer