Header Image: The surface morphology with the magnification of one thousand times of the four kinds of plant leaves: (a) Photinia serrulata, (b) Ginkgo, (c) Aloe vera and (d) Hypericum monogynum. (CC BY-NC-ND 4.0)
Throughout millions of years, organisms evolved in Nature due to a need of adaptation driven by different environmental conditions imposed. Functional systems with intricate properties arose from this continuous structural development leading to, for example, super hydrophobic and self-cleaning surfaces found in lotus leafs (referred as “lotus effect”). An understanding of role of the microstructural features in these systems may help elucidating how to tailor system with an appropriate surface wettability.
In order to tackle this need, Wang and co-workers (2016) studied the wettability properties of four different types of plants (P. serrulata, Ginkgo, Aloe vera, H. monogynum) exhibiting dissimilar microstructures by means of static contact angle for deionized water.
Their results provide an insightful understanding of surface wettability. Whilst minor corrugated and raised boundary microstructures portray the highest wettability (i.e., P. serrulata), increase in cross section corrugation diminishes the liquid/surface contact area and, therefore, intensifies hydrophobicity. Also, the L/W ratio seems to play a major role in surface wettability. Ginko, although displays a corrugated microstructure on the leaf, its large L/W ratio promotes diffusion of liquid, which consequently leads to a hydrophilic surface.
This post was written by Pedro Luiz Lima dos Santos as part of an ongoing series of scientific communications written and curated by BioTrib’s Early Stage Researchers.
Pedro is researching the Functional Biotribology of the Surface Engineering of 3D Printed Components at the University of Leeds, UK.