A Study on the Wetting Properties of Broccoli Leaf Surfaces and their Time Dependent Self-Healing After Mechanical Damage

TL;DR

This study investigates the super-hydrophobic and self-healing properties of broccoli leaf surfaces, revealing their ability to recover surface characteristics after mechanical damage through a multi-step process dependent on surface roughness.

Contribution

It provides new insights into the time-dependent self-healing mechanisms of plant wax surfaces, specifically in broccoli leaves, after mechanical damage.

Findings

Broccoli leaf surfaces are super-repulsive to water, glycerol, and formamide.

Surface properties recover after damage through a multi-step process.

Recovery depends strongly on the restoration of surface roughness.

Abstract

Plants are protected from the elements by a complex hierarchical epicuticular wax layer which has inspired the creation of super-hydrophobic and self-cleaning surfaces. Although many studies have been conducted on different plant wax systems to determine the mechanisms of water repulsion hardly any have studied the recovery of the epicuticular wax layer. In the current study the wetting properties and crystallographic nature of the wax surface of Brassica oleracea var. Italica (broccoli) has been studied, as well as the time-dependent recovery of the surface after mechanical damage. It was found that the surface of the broccoli leaves is not only super-repulsive and self-cleaning in regards to water but also in regards to glycerol and formamide both of which have considerably lower surface tension values. Furthermore, it was shown that the surface properties do indeed recover after damage and that this recovery is multi-steped and strongly dependent on the recovery of the roughness of the surface