Mammalian hair reveals potential limits to composite materials strength

Hair structure and Tensile strength

The tensile strength of hair is increased with decreasing diameter, a mechanical property consistent with Weibull statistics. Credit: Cell Matters

Hair is a remarkable composite material that exhibits a wide spectrum of mechanical properties, ranging from the stiff quills of porcupines to the water-adapted fibers on capybaras, a mammal native to South America, and the largest living rodent in the world. This diversity is made all the more impressive by the fact that, regardless of species, hair is mostly comprised of the same constituent materials. Hair has attracted the attention of materials researchers, considering that a better understanding of its varied properties may lead to the improved design and manufacture of synthetic materials.

Toward this end, Wen Yang, a research scientist working in Marc Meyers’ laboratory at the University of California, San Diego, and her colleagues surveyed the tensile strength of hair samples taken from a myriad of sources. Their results, published in Matter, suggest a relationship exists between the structure, strength, and failure of hair fibers that is predicted by Weibull probability analysis. They conclude that the larger the diameter of a hair fiber, the more likely it is to have an internal flaw and be weaker for it.

Read the full write-up on MRS Bulletin.

Read the Matter article.