Hand-colored scanning electron micrograph (SEM) showing the upper surface of a rose petal (Rosa sp.) by Martin Oeggerli.
Hairs are only present on the lower surface of the leaf. Thousands of finely corrugated warts cause the velvet shimmer on the upper surface of dark red rose petals. Thousands of finely corrugated warts cause the velvet shimmer on the upper surface of dark red rose petals.A superhydrophobic surface is a surface on which a drop of water forms an almost perfect sphere and even a very slight tilting is sufficient to cause the water drop to roll off. Biological tiny structures have been observed on many kinds of surfaces such as lotus leaves, rice leaves, butterfly wings, mosquito eyes, moth eyes, cicada wings, gecko feet, desert beetle, spider silks, fish scales, and red rose petals which exhibit excellent hydrophobicity and/or superhydrophobicity. Understanding the anti-wetting principles of surfaces is of special interest, because properties such as anti-sticking, anti-contamination, and self-cleaning are expected, and therefore surfaces with superhydrophobic properties are attractive for many industrial and biological applications, such as anti-biofouling paints for boats, anti-sticking and self-cleaning windshields and windows, microfluidics, stain resistant textiles, anti-soiling architectural coatings, or dust-free coatings on building glasses, and other biological and technical applications.