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

TL;DR

This paper presents a method to create hydrophobic inorganic coatings on natural lotus leaves using ion beam sputtering, resulting in surfaces suitable for nanoimprint stamps with enhanced water repellency.

Contribution

It introduces a novel technique to fabricate hydrophobic inorganic coatings with lotus-leaf-like structures for use as durable nanoimprint stamps.

Findings

Water contact angles of 136.3° and 117.8° on copper and silicon films

Successful replication of lotus-leaf-like structures on polystyrene

Enhanced hydrophobicity compared to flat inorganic films

Abstract

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{\deg} and 117.8 \pm 4.4{\deg}, 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.