Nanoscale friction of biomimetic hair surfaces

The smoothness and feel of human hair are strongly influenced by the friction between strands. Typically, friction is controlled by surface roughness across a wide range of length scales. In this work, we study the nanoscale friction between two model hair surfaces using molecular simulations and atomic force microscopy experiments. We consider ultrasmooth surfaces at various degrees of chemical damage to mimic both healthy and bleached hair. Our results show that friction is increased on bleached hair compared to virgin hair, which is consistent with measurements on real hair. This friction increase is not due to an increase in surface roughness, but rather a change in surface chemistry. The results of this work could be beneficial for fine-tuning hair care formulations to restore the low-friction properties of healthy hair.

Erik Weiand, James P. Ewen, Yuri Roiter, Peter H. Koenig, Steven H. Page, Francisco Rodriguez-Ropero,  Stefano Angioletti-Uberti and  Daniele Dini