טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentTsipenyuk Alexey
SubjectTribology of Biomimetic Surface Microstructures
DepartmentDepartment of Mechanical Engineering
Supervisors Dr. Yuri Kligerman
Assistant Professor Michael Varenberg
Full Thesis textFull thesis text - English Version


Abstract

The animal body covering is a multifunctional system that represents the interface between living organisms and the environment, at which tribological interactions - adhesion, friction, lubrication, and wear - take place. These interactions are a critical evolutionary factor, which contribute to the appearance of a broad range of specialized surfaces adapted to work across all relevant length scales, from macro- to micro- and nanoscales.

Smooth contact pads that evolved in insects, amphibians and mammals to enhance the attachment abilities of the animals' feet are often dressed with surface micropatterns of different shapes that act in the presence of a fluid secretion. One of the most striking surface patterns observed in contact pads of these animals is based on a hexagonal texture, which is recognized as a friction-oriented feature capable of suppressing both stick-slip and hydroplaning while enabling friction tuning.

Here, we compare this design of natural friction surfaces to textures developed for working in similar conditions in disposable safety razors. When slid against lubricated human skin, the hexagonal surface texture is capable of generating about twice the friction of its technical competitors, which is related to it being much more effective at channeling of the lubricant fluid out of the contact zone. The draining channel shape and contact area fraction are found to be the most important geometrical parameters governing the fluid drainage rate.