Thank frogs’ legs and Technion researchers for getting a smoother shave

Animals that live in a wet environment improve their ability to hold on to things by removing liquid from the surface with special tunnels on their feet.

By JUDY SIEGEL-ITZKOVICH
Shaving legs (photo credit: Wikimedia Commons)
Shaving legs
(photo credit: Wikimedia Commons)
Studying friction of surfaces that imitate tissues in frogs, crickets and salamanders, researchers at the Technion-Israel Institute of Technology have discovered a way to improve significantly the process of shaving.
Prof. Michael Varenberg, a mechanical engineer in the Haifa institute, and colleagues used their knowledge of tribology -- the science of interacting surfaces in relative motion -- to learn how these small creatures that live in wet surroundings don’t slip on wet surfaces.
An article on the research was just published in the journal ITAL Interface END ITAL of the Royal Society of London for the Improvement of Natural Knowledge (commonly known as the “Royal Society”).
Surfaces that imitate biological textures were examined using a "unique device” built by Varenberg’s group that can perform measurements while working inside a scanning electronic microscope. Among the forces at play are friction and adhesion. The device makes it possible to simultaneously view at high resolution how different surfaces function when touching each other.
“We use natural solutions as inspiration for the development of new engineering technologies relating to surfaces,” he explained on Wednesday. “We are doing this in cooperation with biologists who give us data on the functions and complex structures of biological systems that we are trying to simplify and apply using technical means. This process makes it possible to understand how things work in nature, and then we can advance the engineering.”
The Technion team learned that animals that live in a wet environment improve their ability to hold on to things by removing liquid from the surface with the help of special tunnels that exist on the surfaces of their feet. It turns out that a similar problem exists in modern razor blades. A rubber stripe under the razors are meant to increase the friction so as to stretch the skin of a man’s face before the razor passes over it. This creates a closer shave. But when shaving foam is present on the skin, the friction is diminished, and this upsets the stretching of the skin.
To examine genuine razor blades, the researchers took those sold in shops and replaced the original rubber stripe that functions like tiny window wipers with a rubber strip with a hexagonal texture that copies textures that imitate nature. The scientists built the stripe after examining the legs of frogs. They also studied structures on crickets and salamanders.
“The surface that we created in the lab is twice as efficient in increasing the friction with skin coated with shaving cream than the surface of commercial razor blades, said Varenberg, who applied for a patient on this dovery he made with his student, Alexei Tzipaniuk.
“Our surface is also more pleasant when making contact with the skin,” added the student, who carried out friction experiments on the skin of his arm. A scientific poster that Tzipaniuk prepared was recently chosen as one of the three top posters in a competition held by the Technion’s Russell Berrie Nanotechnology Institute.