Constructing Robust and Multifunctional Superamphiphobic Surfaces by Using Two Different Nanostructures of Silicon Dioxide

Superamphiphobic surfaces, combining both superhydrophobic and superoleophobic properties, show tremendous potential applications in various fields. However, the complicated procedures, expensive equipment, and poor mechanical robustness and durability seriously limit their commercialization. In this study, superamphiphobic surfaces have been fabricated by a simple spraying method using two different nanostructures of silicon dioxide. The nanosheet silica (about 80 nm) constructed a large-scale layer structure, and the nanospherical silica (about 30 nm) interweaved with nanosheet silica to form a double-scale "reentrant" micronano structure. The contact angle (CA) and sliding angle (SA) were estimated to be 158° and 1° for a water droplet, while the CA and SA were measured to be 154° and 3° for olive oil, meeting the superamphiphobic requirement. On the other hand, control surfaces that only adopted nanosheet or nanospherical silica just satisfy the superhydrophobic requirement. Owing to the similar chemical components of nanosheet and nanospherical silica, the two mixed very well and were uniformly dispersed, endowing the whole surface with the same superamphiphobic behavior. More importantly, the mixture of nanosheet and nanospherical silica was sprayed on the wet poly(amide-imide) (PAI) substrate, making them easily enter into the PAI film. This unique structure is helpful for improving mechanical robustness and durability. Thus, the surface wettability was nearly unaffected even though it underwent lots of tests, including sandpaper abrasion, ultrasonic treatment, acid-base immersion, UV irradiation, and boiling water jet impact. As expected, the superamphiphobic surfaces show antifouling, self-cleaning, and icing delay performances, and the icing time was prolonged from 55 to 342 s. It is believed that robust superamphiphobic surfaces with multifunctions of antiliquid-adhesion, self-cleaning, anticorrosion, and anti-icing have enormous potential applications in the industrial environment.