A layered sensor for simultaneous measurement of skin water content and softness

In this paper, a layered sensor was developed for simultaneous measurement of skin water content and softness. The sensor consisted of a thin stainless steel film on top of a polyvinylidene difluoride (PVDF) film. Electrostatic and piezoelectric effects generated voltages which were measured simultaneously in the stainless steel and PVDF films while the sensor was repeatedly in contact with/released from the skin. The voltages in the films depended on the skin water content and softness. The layered sensor measured the skin water content and softness at the same position using the voltage waveforms. The relationships between the voltages obtained using the layered sensor and results obtained with commercial moisture and softness sensors were evaluated. The potential of the proposed sensor for skin condition measurements was evaluated.