Icing delay of sessile water droplets on superhydrophobic titanium alloy surfaces

Abstract

Superhydrophobic surfaces have been widely considered and expected to play an important role in promoting anti-icing performance. In this research, superhydrophobic surfaces based on titanium alloy were fabricated by combining laser processing and further chemical modification. Surface morphology and wettability were characterized with scanning electron microscopy and contact angle measurement, respectively. Icing behaviors of sessile water droplets on smooth hydrophilic, smooth hydrophobic and superhydrophobic surfaces, maintained at subzero temperatures, were investigated under a humidity condition on a self-built apparatus. The effects of surface wettability, morphology and temperature on droplet icing were analyzed. Results show that droplet icing is remarkably delayed on the superhydrophobic titanium alloy surfaces through the temperature range. Decreasing surface temperature, the extended time for the cooling stage and the freezing stage in sequence dominates the total icing delay. It was also observed that the icing delay of water droplets is more obvious on the pitted superhydrophobic surface than on the grooved one, due to the larger liquid-air interface fraction. This study provides an effective approach for fabricating superhydrophobic surfaces to resist icing on titanium alloy.