Visualizing contact line phenomena on microstructured superhydrophobic surfaces

The presence of microstructures or nanostructures on a surface can influence how that surface interacts with liquids. When simple surface roughening techniques are employed, increased surface area amplifies the natural sur- face chemistry: hydrophilic surfaces become more hydro- philic upon roughening, and hydrophobic surfaces become more hydrophobic. While the interaction between the drop- let and the surface microstructures is understood to control the macroscopic wetting dynamics, few experimental meth- ods have been reported to study the microscopic interaction between a droplet and a microstructured surface. This article reports metrology of microscopic contact line phenomena via metal droplets frozen onto a microstructured surface.