Laser-based functionalization for superhydrophobic silicon carbide with mechanical durability, anti-icing and anti-fouling properties

The further applications of silicon carbide (SiC) are limited due to the ease of being contaminated and tendency for icing at low temperature caused by its intrinsically hydrophilicity. In recent years, superhydrophobic surface has been widely employed due to the potential value in anti-fouling and passive anti-icing. In this work, a novel laser ablation-silicone oil heat treatment (LASH) composite process is proposed to fabricate superhydrophobic SiC surface. Many microscale "fence" structures and nanoscale "broccoli" fragmental structures are successfully obtained, which can be adjusted by using different laser processing parameters. Besides, the X-ray photoelectron spectroscopy analysis demonstrates that the effective deposition of low surface energy chemical functional groups is the key to realize the superhydrophobic properties of SiC surface. The coupling effect between the micro/nano structures and low surface energy is confirmed to be important for the stability of Cassie-Baxter state at low temperature. In addition, the freezing process of water droplets on the LASH surface at low temperature and the mechanism of the rapid transition from Wenzel state to Cassie-Baxter state are analyzed. The experimental results indicate that the LASH surface possesses a longer static icing time and keeps good hydrophobicity at -5 degrees C. The icing temperature of the LASH surface decreases to -17.6 degrees C while the temperature of the untreated surface is -3.7 degrees C. Moreover, the LASH surface possesses a lower ice adhesion strength which means it is easier for the ice droplets to break away from the surface. After 20 cycles of icing-deicing experiments, the WCA of the LASH surface is still higher than 150 degrees and its ice adhesion strength slightly increases to 240 kPa. Finally, the mechanical robustness of the LASH surface is studied through the abrasive belt and tape stripping tests, and the anti-fouling property is also evaluated. The change of ice adhesion strength on the LASH surface under cyclic icing experiment is analyzed. The experimental results show that the LASH surface has great mechanical durability and anti-fouling property, which is expected to further expand the application prospects of SiC in different fields.