Super-hydrophobic surfaces

It is well observed in nature that to achieve surfaces with high hydrophobicity, proper surface roughness is required in combination with correct surface chemistries. Presently we are studying the optimum surface roughness required for highest contact angle and lowest rolling angle. We are preparing ultra-hydrophobic organo-silica films using a sol-gel process. We have visually identified self-cleaning action and bouncing of the liquid drops on ultra-hydrophobic aerogel materials.