Freezing a water droplet on an aligned Si nanorod array substrate

Abstract

When a water droplet is dried on a vertically aligned Si nanorod array surface, the nanorods are bundled together. To understand how bundles are formed, a water droplet is frozen rapidly on a Si nanorod array surface observed under a cryo-SEM (scanning electron microscope). The nanorods in the precursor film form similar bundles as those dried in air. But the nanorods under the apparent frozen water droplet are only slightly deformed. We propose that the bundling of nanorods is caused by non-uniform water-nanorod interaction, which could happen either during the water spreading or drying process. Therefore, controlling the liquid-nanostructure interaction could minimize the bundling. In addition, the rapid freezing process does not preserve the water inside the nanochannels, and almost all the water forms ice on top of the nanorod surface, either as a planar interface or as particles, depending on the locations. The separated ice-nanorod interface will have potential applications in chemical separation and crystal growth.

Perspectives on oblique angle deposition of thin films: From fundamentals to devices

“…Indeed, the nanocarpet effect has already served to increase the WCA on 1D surfaces [563,573] through the formation of a double or hierarchical roughness. From a fundamental point of view, it has also been used to provide a fingerprint of liquid droplets deposited on vertically aligned, tilted, zigzag and squared spring conformations of hydrophilic or hydrophobic materials [573,579]. In Ref.…”

Fabrication of a novel aluminum surface covered by numerous high-aspect-ratio anodic alumina nanofibers

“…2f), the alumina nanofibers increased in length to several hundred nanometers, and several nanofibers became tangled and bundled together due to bending under their own weight. These bundles may be structured by the surface tension and adsorption of each nanofiber via drying of distilled water on the surface after specimen washing [55]. After anodizing for 30 min (Fig.…”

Directional growth of nanocrystalline Si nanorod array by mid-frequency magnetron sputtering

“…Up to now, one‐dimensional silicon nanostructures have been successfully prepared by various chemical or physical methods, such as chemical vapor deposition (CVD), laser ablation, vapor–liquid–solid (VLS), sputtering, e‐beam evaporation, etc. Among these techniques, magnetron sputtering or e‐beam evaporation combined with glancing angle deposition (GLAD) mode has been reported to be superior to fabricate Si nanorods because of non‐toxic, efficient, and easy to design and sculpt the nanorod structures by adjusting the oblique angle and the substrate rotation . However, the silicon nanorods prepared by the above‐mentioned method are almost amorphous.…”