Superhydrophobic Coatings and Their Durability

Superhydrophobic coatings with contact angles (CAs)>150 degrees and sliding angles (SAs)<10 degrees have become the focus of research and industrial development studies for water repellency applications. Furthermore, superhydrophobic coatings have shown to reduce ice adhesion by means of their low surface energy chemistry and nano/micro roughness. Superhydrophobicity can be achieved by combining the chemistry and the roughness of the surface, inspired by the lotus leaf composition and structure. Durability enhancement of superhydrophobic surfaces is a critical issue for commercial and industrial applications. Consequently, the use of superhydrophobic surfaces in practical applications is limited due to their poor mechanical abrasion resistance and hostile environmental conditions. Covalent bonding of the micro/nano particles to the binder material was identified as essential for durability enhancement. This review summarizes the state of the art of the design, preparation techniques of durable superhydrophobic coatings and the characterization techniques for durability evaluation.