Controlled Hydration in Epidermal Ridges Probed by THz Time-Domain Spectroscopy
International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz
Yum S.-M., Baek I.-K., Hong D., Kim S., Eom K., Jang J., Kim S., Sattorov M., Lee M.-G., Kim S., Adams M., Park G.-S.
Abstract
Fingerprints are common to humans, primates, and koalas but how their role in grip activities is poorly understood. Here, we reveal that the fingerprints control the hydration level of the fingertip, as required for precision gripping, by ultimately maximizing the friction. Electromagnetic waves with frequencies in the megahertz, terahertz, infrared, and visible ranges were used to identify the hydrodynamics in fingerprints, which lead to the steady-state hydration condition in 'dry' and 'wet' conditions. The results suggest that the fingerprint structure functions as a moisture channel for facilitating precision grip. © 2019 IEEE.