Role variability of surface chemistry and surface topography in anti-icing performance.

Largely varied anti-icing performance among superhydrophobic surfaces remains perplexing and challenging. Herein, the issue is elucidated by exploring the roles of surface chemistry and surface topography in anti-icing. Three superhydrophobic surfaces, i.e., gecko-like, petal-like, and lotus-like surfaces, together with smooth hydrophobic and hydrophilic surfaces, are prepared and compared in ice nucleation temperature under both non-condensation and condensation conditions. As a result, in non-condensation condition, water droplet freezing is caused by interfacial heterogeneous nucleation, wherein both surface chemistry and surface topography contribute to deferring freezing, and the former is dominant. In condensation condition, the freezing strongly correlates to condensation frosting. Surface chemistry maintains as a strong deterrent, whereas surface topography has two competing effects on the freezing. The paper deepens the understanding of water freezing on superhydrophobic surfaces, unravels the correlation between superhydrophobicity and anti-icing, and provides design guidelines on application-oriented anti-icing surfaces.