Selection of second step micro-morphology for anti-icing surfaces based on icing time

Abstract

Superhydrophobicity are associated with surface two-step micro/nanostructure together morphology. However, it is uncertain for Superhydrophobic surface (SHS) whether having anti-icing ability if without detailed knowledge of the surface morphology. For this reason, we proposed a three-dimensional (3-D) icing model to analyze anti-icing properties and determine the second step morphology suitable for the anti-icing. Followed by it, representative samples (hydrophobic or hydrophilic, metal or nonmetal, organic or inorganic) were selected for freezing measurement to confirm theoretical results. Ranked order is a sine wave/cone frustum/prism/cylinder/cuboid/paraboloid, and a semi-sine-wave model by the anti-icing time from high to low. The anti-icing property still depends on the surface micro-scale and micro-morphology to a great extent as hydrophobicity does. Effect of morphology on anti–icing will be significantly reduced even neglected, if the solid–liquid contact fraction being small enough. Meanwhile we also found that both the time for drop in temperature and the icing time are directly related to the solid fraction, whether the freezing singularity appears depends on freezing velocity or hydrophilicity. The predictions of the model largely agree with the experimental observations, also opening up possibilities for rational design of anti-icing SHS by selecting suitable morphology in micro scales.