F2-laser-induced micro/nanostructuring and surface modification of iron thin film to realize hydrophobic and corrosion resistant

Abstract

Nanoswellings of 60 nm height and 500 nm diameter on average of an iron thin film deposited on a silica glass substrate at regular intervals of 2.5 µm were fabricated by the irradiation of a 157 nm F2 laser. The F2 laser was focused on the iron thin film by each microsphere made of silica glass of 2.5 µm diameter, which covered the entire surface of the films. The surface of the silica glass substrate underneath the F2-laser-irradiated iron thin film selectively swelled to push up the film. After the laser-induced micro/nanostructuring, the F2 laser was again irradiated onto the entire surface of the periodic micro/nanostructured iron thin film to form an approximately 2-nm-thick Fe3O4 modified layer. As a result, the samples showed hydrophobicity and high corrosion resistance to 3 wt % NaCl aqueous solution (quasi-seawater). No rust was observed on the samples after the immersion test in the quasi-seawater for 24 h.