Superhydrophobic surfaces have applications in self-cleaning of buildings, solar panels, vehicles, and textiles. Superhydrophobic surfaces can be used in drag reduction and increasing heat transfer rates via drop-wise condensation.
Hierarchical surfaces composed of microscale structures coated with nanoscale texturing have been fabricated using direct molding, etching, deposition, and growth techniques. However, this technology uses biological templates – the tobacco mosaic virus (TMV) – for the guided assembly of inorganic materials, which has several advantages including simple and low-cost fabrication, structural versatility, and the ability to tune structures through genetic modifications.
Superhydrophobic surfaces can be created using nanoscale features alone. However, naturally occurring self-cleaning surfaces (e.g. Taro plant, Myrtle Spurge plant, and the Lotus plant) exhibit hierarchical micro- and nanoscale structures. Through investigating this technology, it was realized that these hierarchical structures allow surfaces to retain superhydrophobicity under dynamic droplet impact (i.e. rain). Microscale pillars were created using a photo-definable polymer patterned onto a silicon substrate, followed by conformal self-assembly and metallization of the TMV. The final step is an atomic layer deposition of aluminum oxide followed by vapor deposition of trichlorosilane. However, the use of TMV enables direct patterning over a wide range of materials (including metals, ceramics, and polymers). The ability to use different materials allows broader applications of this technique. For example, if the application needs to be electrically conductive but also hydrophobic then a metal can be used.
Simple and low-cost fabrication
Enables superhydrophobicity under dynamic droplet impact