Fabrication of hydrophobic inorganic coatings on natural lotus leaves for nanoimprint stamps

Hydrophobic inorganic films were obtained by direct deposition of copper or silicon onto natural lotus leaves by ion beam sputtering deposition technique. Scanning electron microscopy observations showed a lotus-leaf-like surface structure of the deposited inorganic films. Hydrophobic nature of the inorganic films on lotus leaves had been improved compared to the inorganic films deposited on flat silicon substrates. Water contact angles measured on the lotus-leaf-like copper and silicon films were 136.3 \pm 8° and 117.8 \pm 4.4°, respectively. The hydrophobic lotus-leaf-like inorganic films had been repeated used as nanoimprint stamps. Negative structures of lotus-leaf-like inorganic films were obtained on the polystyrene resist layers.