Coronamicroparticle Arrays with Stable Superamphiphobicity.

Springtails use reentrant nanostructures to repel both water and oil liquids, inspiring scientists to construct reentrant nanostructures for superamphiphobic surfaces. However, the packing density of the reentrant nanostructures related to their liquid repelling performance is generally limited on a planar surface. Packing reentrant nanostructures on curved surfaces can greatly increase the packing density, however fabrication of reentrant nanostructures on curved surfaces is a great challenge. Here, we develop a method to fabricate reentrant nanostructure arrays on polystyrene (PS) microsphere surfaces, giving rise to the formation of coronamicroparticles with the morphology resembling corona virus. The critical step to fabricating the coronamicroparticles is that a silver nanomesh is transferred onto the PS microspheres to form a conformal coating layer. Thermal evaporation of gold through the silver nanomesh formed gold nanodisk arrays on the PS microspheres. Consequent reactive ion etching of the gold nanodisk-protected PS microspheres gives rise to the formation of coronamicroparticle arrays. The morphology of the coronamicroparticles can be simply adjusted by the size of the PS spheres and the reactive ion etching time. The coronamicroparticle arrays demonstrate stable superamphiphobicity, suggesting potential applications in self-cleaning, liquid transportation, and sensing fields.