Biomimicked high-aspect-ratio hierarchical superhydrophobic polymer surfaces

There is an abundance of plant surfaces in nature, which inspires scientific community to replicate and prepare artificial superhydrophobic surfaces. However, most of these studies are limited to low-aspect-ratio structures as found in petals and leaves. In this study, the authors chose Canna indica, a garden plant belonging to Cannaceae family, as a model plant. The C. indica seedpods possess high-aspect-ratio multiscale structures and also show superhydrophobic behavior. These high-aspect-ratio hierarchical structures as found in C. Indica seedpod were then successfully replicated by replica molding in different polymers such as poly(dimethylsiloxane) (PDMS) and resorcinol-formaldehyde (RF)based xerogel. These biomimicked polymer surfaces exhibit superhydrophobicity as confirmed by water contact angle measurement. The original seedpod shows water contact angle of 151, while negative PDMS and RF gel replica with high-aspect-ratio structural patterns show water contact angle of 146 and 155, respectively. Thus, the biomimetic approach depicted here not only allows the facile fabrication of high-aspect-ratio structures over a large area but also provides a low-cost alternative to produce superhydrophobic polymer surfaces.