Ice-fouling on superhydrophobic and slippery surfaces textured by 3D printing: revealing key limiting factors

Solid surfaces, subjected to subzero temperatures, experience ice-fouling that poses a substantial economic burden to various industries (e.g. energy, transportation, aviation, building). Employing repellent surface chemistry on engineered surfaces (e.g. pillar, tubular, porous) delays icing and reduce ice adhesion. However, the limiting parameters that fail the icephobic properties of "slippery" and "superhydrophobic (SH)" surfaces are not well explored. Herein, we introduce anodized and chemically modified "slippery", and "SH" surfaces textured by 3D-printing to justify their ice-phobic properties considering the influencing factors, namely surface energy and roughness, temperature and humidity gradient, and droplet-to-surface contact area. Although "slippery" and "SH" surfaces can resist ice nucleation for a few hours at moderate subzero temperatures, they fail when the temperature drops to -12 degrees C. Despite posing -10 times lower adhesion strength (i.e. shear stress) than the control, "SH" surface with moisture-induced micro ice-crystals exhibited twice the ice-adhesion measured without the presence of micro ice-crystals on it. In contrast, the "slippery" sample, due to antifreeze properties, did not get affected by the presence of moisture-induced micro ice-crystals, exhibiting -17 times lower adhesion strength than the control substrate. The comparative aspects and explored limiting factors of icing on "slippery" and "SH" surfaces are significant for many industries that suffer from ice-fouling.