Superhydrophobic and oleophilic micro‐nano hierarchical Pd‐decorated SiO 2 layers

This paper reports a novel fluorinated micro‐nano hierarchical Pd‐decorated SiO 2 structure (hereafter called Pd/SiO 2 ), which was formed by the deposition of Pd nanoparticles ( NP s) on SiO 2 microspheres. The SiO 2 layers with microscale roughness were fabricated by electrospraying a solution prepared using the sol‐gel process. Subsequently, the Pd NP s were deposited using an ultraviolet reduction process. The resulting surfaces exhibited a micro‐nano hierarchical morphology. After fluorination, the micro‐nano hierarchical surface exhibited outstanding water repellency with a water contact angle ( WCA ) of 170° and a sliding angle <5°, indicating excellent superhydrophobic properties. The layers exhibited good long‐term durability and excellent ultraviolet resistance. Interestingly, the surface was oleophilic ( CA of oil ~10°). These results show the potential of employing superhydrophobic fluorinated Pd/SiO 2 layers in smart devices, such as self‐cleanable surfaces and intelligent water/oil separation systems.