Robust and easy-repairable superhydrophobic surfaces with multiple length-scale topography constructed by thermal spray route

• Coating with multiscale structure was made by thermal spray and nano modification.
• Ceramic matrix with cone-like geometry was fabricated by plasma spray deposition.
• The superhydrophobic surfaces are mechanically robust and easy-repairable.

This paper demonstrates a thermal spray route for making superhydrophobic surfaces with mechanically robust and easy-repairable performances. Cone-like geometry with multi-scale topographical structures was firstly achieved by plasma spray deposition of titania using stainless steel mesh as shielding plate, then polytetrafluoroethylene/nano-copper composites were deposited by suspension flame spray onto the patterned titania coating. The coatings exhibit superhydrophobicity with a water contact angle of ∼153° and a sliding angle of ∼2°. Unlike the surfaces with normal structure, the coatings with multiple length-scale structure retain the superhydrophobicity even after severe mechanical abrasion. The superhydrophobicity can be further easily restored after it is damaged by abrasion. The thermal spray construction of superhydrophobic surfaces proposed in this research offers the advantages of precisely tailoring the surface textures and surface chemistry cost-efficiently over as large an area as desired, showing bright prospects for versatile applications.

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