A simple method to generate hierarchical nanoscale structures on microwrinkles for hydrophobic applications

• Simple way to make hierarchical structure having nanoscale structures on microwinkles.
• Fabrication method of microwrinkles using a repetitive dividing volume (RDV) technique.
• Parameter study to generate fine microwrinkles in the RDV process.
• Generation of nanoscale protrusions having tens to hundreds nanometers in size.
• The hierarchical structures have superhydrophobic characteristics.

We propose an effective method of fabricating hierarchical nanoscale structures on microwrinkles for use in diverse applications. To do this, we introduce a wrinkling process to engender fine wrinkles using a method of repetitive dividing volume of ultraviolet curable resin. A plasma treatment technique then generates nanoscale protrusions on the microwrinkles. With this simple two-step process, we create interesting hierarchical micro- and nanoscale structures that exist in natural objects, such as the surface structure of a lotus leaf. We investigate changes in the contact angles on a flat, hierarchical structure. The proposed method presents a simple means of creating micro- and nanoscale hierarchical structures for hydrophobic and biomimetic applications.