Durable and self-healing superhydrophobic surface with bistratal gas layers prepared by electrospinning and hydrothermal processes

In this work, a novel bistratal gas layer structure has been used to enhance the long-term durability of a superhydrophobic surface. The design of this bistratal structure takes inspiration from the wings of the insect Notonecta glauca and a spider web. It is comprised of an underlying semi-interpenetrating array structure and a superficial microfiber network structure. On modification with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS), the prepared surface demonstrates an excellent superhydrophobicity with a water contact angle (WCA) of 168 ± 1.4° and a sliding angle (SA) of 4 ± 0.5°. The underlying semi-interpenetrating array structure can capture more gas to form a stable underlying gas layer, which enhances its anti-static pressure capability. When the superhydrophobic surface was impacted by a high-pressure water column (250 kPa), the superficial micro fibers network structure acted as a buffer layer to disperse the impact force that spread over the network. The prepared surface with bistratal gas layer structure was thus able to high speed water jetting (22.4 m s−1), which is three times the speed of the heavy rain (7–9 m s−1) and four times that reported for polysiloxane/multiwalled carbon nanotubes (POS/MWCNTs) surfaces (5.4 m s−1). Furthermore, the superhydrophobic surface designed by this method was also shown to possess self-healing and hot-water-repellent (100 °C) capability. These features demonstrate the practical potential of superhydrophobic surfaces with a bistratal gas layer structure.