Porous PDMS pulsewave sensors with haircell structures for enhanced water vapor transmission rate and signal to noise ratio

Abstract

We have proposed the porous PDMS pulsewave sensors with haircell structures that improve water vapor transmission rate and signal to noise ratio through the use of porous PDMS layers and haircell structures. The water vapor transmission rate is improved by the thin-thickness and high-porosity PDMS layers, fabricated by the crystallization of citric acid particles inside the PDMS. The signal to noise ratio is enhanced by the haircell structures, properly designed to increase skin contact area. The fabricated porous PDMS pulsewave sensors with haircell structures increase both water vapor transmission rate and signal to noise ratio. The porous PDMS pulsewave sensors with haircell structures show the 27 % higher water vapor transmission rate (486.17 g/day/$m^2$) and the 757 % higher signal to noise ratio (22.89), compared to the previous PDMS pulsewave sensors with flat structures. Furthermore, the present sensors achieve the water vapor transmission rate, which is 13 % higher than the skin requirement (432 g/day/$m^2$). The porous PDMS pulsewave sensors with haircell structures are capable for a long-term use with the lower skin irritation and the enhanced signal to noise ratio.