Electrochemical 3D printing of superhydrophobic pillars with conical, cylindrical, and inverted conical shapes

Meniscus-confined electrochemical three-dimensional (3D) printing is an effective method for fabricating metal pillars, which have huge application prospects in the fields of anti-icing, oil/water separation, and oil-repellence. However, this method is only applicable for fabricating cylindrical pillars with uniform diameters, and there is still no universal method for fabricating conical, cylindrical and inverted conical pillars. Here, a universal method based on meniscus-confined electrochemical 3D printing was proposed to prepare conical, cylindrical, and inverted conical pillars. First, the meniscus-shaped liquid/air interface was divided into three parts: conical, cylindrical, and inverted conical parts. Then, numerical simulation was conducted to investigate growth processes of the deposition layer. The results indicated that the deposition layer consistently grew at the conical, cylindrical, or inverted conical part, thus forming conical, cylindrical, or inverted conical pillar, respectively. Finally, pillars with conical, cylindrical, and inverted conical shapes were successfully fabricated by electrochemical 3D printing technology, and three types of pillar arrays were also constructed on Cu substrates. After low energy modification, surfaces with the pillar arrays exhibited excellent superhydrophobicity. This work is expected to enrich the theory and technology for preparing superhydrophobic pillars with variable diameters.

Automated summary

A novel method was proposed in this study to prepare conical, cylindrical, and inverted conical pillars using meniscus-confined electrochemical 3D printing. Pillar arrays with excellent superhydrophobicity were successfully fabricated on Cu substrates, enriching the theory and technology for preparing superhydrophobic pillars with variable diameters.