Lotus leaf-like Ni-decorated SiC with combined superhydrophobicity and enhanced microwave absorption performance

The m-(Ni@SiC)(p) composite particles were firstly prepared by surface chemical modification of industrial coarse-grained SiC particles [named as (SiC)(p)] using a simple and environmentally friendly electroless plating method. Unexpectedly, it is occasionally found that the (Ni@SiC)(p) possess superhydrophobic properties with contact angle of 156 degrees after storage for a long period (> 360 days). The obtained particles [named as s-(Ni@SiC)(p)] can form a superhydrophobic film with lotus leaf effect when they are mixed with water. To reveal the underlying formation mechanism of the surprising superhydrophobicity, systematic morphology-composition characterization was carried out. It shows that the microstructure of the surface of s-(Ni@SiC)(p) is similar to that of natural lotus leaf with numerous random distributed papillae-like protruded pillars. Combined with XRD and XPS analysis, this surprising superhydrophobicity is attributed to the spontaneous formation of unique micro/nano hierarchical rough surface with some Ni oxidizing to NiO under ambient condition during long-term storing. More importantly, they can exhibit excellent microwave absorption performance. When the sample thickness is 2.0 mm, the minimum reflection loss value is -35.78 dB. Moreover, when the thickness is 1.5 mm, the minimum reflection loss value is -20.3 dB and the effective absorption bandwidth is 2.6 GHz. Our results demonstrate that this simple yet effective method can improve both hydrophobic properties and microwave absorption performance, further expanding the potential application scopes of SiC-based materials.

Automated summary

The m-(Ni@SiC)(p) composite particles were prepared by modifying industrial coarse-grained SiC particles through a simple and environmentally friendly method. Surprisingly, the stored (Ni@SiC)(p) particles exhibited superhydrophobic properties with a contact angle of 156 degrees. This was attributed to the formation of a unique micro/nano hierarchical rough surface with some Ni oxidizing to NiO during long-term storage, resembling the microstructure of a natural lotus leaf.