Novel superamphiphobic surfaces based on micro-nano hierarchical fluorinated Ag/SiO2 structures

Abstract

In this study, a novel micro-nano hierarchical fluorinated Ag/SiO2 structure having both superhydrophobic and superoleophobic properties is presented. SiO2 layers with microscale roughness were fabricated using a combination of sol-gel and electrospraying processes. Nanoparticles of silver were deposited on SiO2 using a UV reduction method; subsequent fluorination treatment resulted in micro-nano hierarchical fluorinated Ag/SiO2 layers. The micro-nano hierarchical fluorinated Ag/SiO2 layers have outstanding repellency towards different liquids including water, with a water contact angle of 170 degrees and sliding angle of 1 degrees. This demonstrated the excellent superhydrophobic nature of the micro-nano hierarchical structures. Long-term durability, durability of ex-situ and in-situ fluorinated Ag/SiO2 layers in harsh environments, and ultraviolet resistance of the superhydrophobic fluorinated Ag/SiO2 layers were studied. Thermal stability studies showed that the superhydrophobic properties were retained even at 400 degrees C for 10 h, indicating the good thermal resistance of the fluorinated Ag/SiO2. Finally, the fluorinated Ag/SiO2 structure showed outstanding superoleophobicity (contact angle of 158 degrees) towards mineral oil, which demonstrates the superamphiphobic nature of the micro-nano hierarchical fluorinated Ag/SiO2 structures. Such superamphiphobic fluorinated Ag/SiO2 layers can be used to produce self-cleanable, anti-fogging, anti-bacterial, anti-reflection, and anti-icing surfaces. (C) 2018 Elsevier B. V. All rights reserved.