A new study is throwing cold water on the idea that superhydrophobic surfaces are effective at repelling ice (Langmuir,10.1021/la104). Researchers led by Sergei A. Kulinich of the University of Quebec, Chicoutimi, have performed a systematic study of rough superhydrophobic surfaces to see how the materials hold up over time and under various conditions. Such materials have previously been reported to repel ice by causing water to bead up and roll off their micro- and nanotextured surfaces before it ever has a chance to freeze. Kulinich’s group found that this ice-repellent behavior gradually diminishes with repeated icing and deicing cycles as the ice apparently damages the surface micro- and nanostructures. Furthermore, they found that the anti-icing materials did not perform well in humid environments where water was concentrated throughout the rough surfaces. “This work thus shows that superhydrophobic surfaces are not always ice-repellent and their use as anti-ice materials may therefore be limited,” the researchers note.