The wetting of gold and silicon nanoscale arrays

The relative hydrophobicity of surfaces containing highly regular, nanoscale (<100 nm) topological features (50 nm diameter, 5 nm height, 100 nm spacing) was measured and compared with their flat counterparts. The results are described in the context of both the Wenzel and Cassie models for wetting rough surfaces. Wenzel-type wetting is observed for these high areal density nanostructures (approximately 10(10)/cm2) whose aspect ratios range from 0.2 to 0.7.