Self-Healing Superhydrophobic Surfaces: Healing Principles and Applications

Superhydrophobic surfaces have already been applied in anti-fouling, water-oil separation, liquid transportation, etc. Surfaces can be defined as superhydrophobic surfaces once they can support a water droplet with its spherical shape maintained and accompanied by an apparent contact angle larger than 150 degrees and a rolling-off angle below 10 degrees. Such water repellent property is achieved by the synergetic action of hierarchical structures and the low-surface energy of the substances constructing the surface. Structures with high aspect ratio always perform good superhydrophobicity. However, they are usually with poor mechanical stability. Since durability is one of the essential factors for practical use, exploiting robust superhydrophobic surfaces has attracted tremendous interest. During the past decade, great effort has been made in developing self-healing superhydrophobic surfaces to improve the potential practice and broaden the application fields. An overview of the recent development of self-healing superhydrophobic surfaces is provided in this review. The focus here is particularly on the fabrication process based on specific healing mechanisms and possible applications. Finally, an outlook on future fabrication techniques for durable superhydrophobic surfaces is presented.