Recoating/plasma driven rewritable and erasable superhydrophobicity on CuO surfaces

The present work reports a simple way to achieve rewritable and erasable superhydrophobicity on CuO surfaces. The as-prepared CuO surfaces show superhydrophilicity with a water contact angle less than 5°. When being chemically modified with octadecanethiol (ODT), the wettability of CuO surfaces changes to superhydrophobicity, just like using a pencil to write something on a piece of blank paper. After being treated with air-plasma, the superhydrophobicity can be erased and the original superhydrophilicity can be recovered, which works the same as you use an eraser to erase the words written on the paper. In addition, the rewritable and erasable wettability between superhydrophobicity and superhydrophilicity can be achieved on CuO surfaces by the ODT recoating and air-plasma treatment alternatively. The reversibly procedure has been switched with full reproducibility more than five times, exhibiting good rewritable and erasable superhydrophobicity on the CuO surfaces.