טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentRich Benjamin
SubjectA Study on the Wetting Properties of Broccoli Leaf Surfaces
and their Time Dependent Self-Healing After
Mechanical Damage
DepartmentDepartment of Materials Science and Engineering
Supervisor Professor Boaz Pokroy
Full Thesis textFull thesis text - English Version


Abstract

Plants have evolved complex surfaces called cuticles to protect themselves from their environment. The cuticle acts as a boundary between the plant and its environment and covers the majority of plant organs. The microstructure of the plant cuticle is extremely diverse as different species of plants have different cell formations, different surface folds, and varying microstructure of their epicuticular wax crystals. Since there are many different wax compositions the epicuticular wax crystals present different morphologies which can contribute to the variation in properties of the surfaces.

The cuticle has many functions, foremost of which is to serve as a transport barrier and reduce water loss. The cuticle can also reduce or increase surface wettability and serves to give the plant anti-adhesive, anti-biofouling, and self-cleaning properties. Finally it can also provide protection from harmful radiation and reduction of surface temperature. 

Biomimetic research deals for the most part with translating biological effects to practical engineering solutions for day to day problems. Prominent examples of biomimetic applications in relation to plant surfaces can be seen in the development of super-hydrophobic surfaces based on the Lotus phenomenon. The potential application of super-hydrophobic surfaces in the industry is great and so there is motivation to study biological systems with interesting wetting properties. 

The objective of this research is to evaluate the recovery of wetting properties of the Brassica oleracea var. italic (i.e. broccoli) surface after mechanical damage. This is relevant as at the moment the use of self-cleaning surfaces is limited by the fact that the micro- and nano-scale structures in said surfaces are very susceptible to wear and so must be constantly maintained. Furthermore we strove to study the physical the broccoli wax itself; from a crystallographic, chemical, and thermodynamic point of view.