Langmuir, Vol.30, No.48, 14469-14475, 2014
Creation of Superwetting Surfaces with Roughness Structures
In this work, we explored the possibility of creating superwetting surfaces, which are defined here as those with apparent contact angles of <5 degrees, using roughness structures for the purpose of eliminating the surface tension effect on a floating small plate, which is denser than the surrounding liquid. The roughness ratio is often thought to play a critical role in generating superwetting surfaces. However, we found that the top surface ratio had more influence on apparent contact angles. When this ratio was <0.013, the resulting apparent contact angle might be less than 5 degrees, when the intrinsic contact angle was >= 40 degrees. Accordingly, hybrid micro- and nanostructures, which had such a small ratio, were chosen to create the superwetting surfaces. These surfaces were subsequently applied to eliminate the surface tension effect on a small plate. As a result of this elimination, the small plate sank down to the bottom of the liquid.