2.4.2. Scanning Electron Microscopy

The morphologies of the hydrophobic silica and the resulting coatings were examined by field emission scanning electron microscope (FE-SEM) using a Hitachi S-4800 FE-SEM from Hitachi High Technologies Corp. (Tokyo, Japan). For cross-section visualization, the samples were cryo-fractured using liquid nitrogen. The materials were sputtered with a gold-palladium thin layer for 2 min under vacuum prior to analysis. An electron beam acceleration voltage of 5 kV and a working distance of 8–10 mm were applied. Image analysis was carried out using ImageJ 1.52a software (National Institutes of Health, Bethesda, MD, USA).