A green, maskless, and universal preparation method for patterned surfaces on various metal substrates

Superhydrophobic surfaces with hydrophilic patterns are widely used in liquid transport, water collection, and cell screening. However, the preparation process of these patterned surfaces tends to be time-consuming and complicated. Here, we apply a simple, efficient and versatile laser processing method. Superhydrophobic substrates are firstly constructed by laser treatment and fluoroalkylsilane (FAS) solution; then superhydrophilic patterns such as dot-shaped or linear grooves are processed by secondary laser treatment. The dot-shaped grooves have strong adhesive force to droplets, and the linear grooves show obvious anisotropic adhesion behavior. On the basis of these features, applications like liquid transport, droplets grabbing and mixing, and fog collection are successfully achieved. The proposed laser processing method is applicable for various metal substrates including aluminum, copper, steel and titanium, and is expected to have promising application prospects in lab-on-a-chip system and chemical analysis domains.