A known family of rare-earth oxide ceramics turns out to be intrinsically water-repellent and sustains the hydrophobicity after exposure to harsh environments, reports a study published online in Nature Materials this week. Ceramics with durable hydrophobicity are needed in a broad range of applications, such as in the avoidance of ice build-up on aircraft or where self-cleaning and corrosion-resistant surfaces are essential.
Durable materials, such as metals and ceramics, are typically hydrophilic. To make them hydrophobic scientists use polymeric coatings, but these quickly degrade in aggressive environments. Kripa Varanasi and colleagues find that a class of ceramics repel impinging water droplets because of their unique electronic structure, which leads to the inhibition of hydrogen bonding with interfacial water molecules, even after the ceramics have been exposed to abrasive wear and to temperatures above 1,000 °C.