Multifunctional Electronic Skin With a Stack of Temperature and Pressure Sensor Arrays

This paper presents multifunctional electronic skin (e-Skin) with a stack of pressure and temperature sensors arrays. The pressure sensor layer comprises of an 8x 8 array of capacitive sensors using soft elastomers as the dielectric medium and the temperature sensing layer comprises of 4 x4 array of conductive polymers based resistive sensors. Three variants of capacitive pressure sensors were developed using two different dielectric materials (PDMS and Ecoflex) to find the best combination of performance and softness. The Ecoflex-based pressure sensor showed high sensitivity (~4.11 kPa
⁻¹
) at a low-pressure regime (< 1 kPa) and the 7.5:1 PDMS based pressure sensor showed high sensitivity (~2.32 kPa
⁻¹
) in the high-pressure regime (>1 kPa). Two variants of temperature sensors were fabricated using CNT and CNT & PEDOT:PSS conducting polymer composite and their performance compared. Finally, a highly sensitive CNT+PEDOT:PSS based resistive temperature sensors layer was integrated on top of 7.5:1 PDMS based capacitive pressure sensors layer to realize the e-Skin prototype. The developed e-Skin is capable of sensing pressures greater than 10 kPa with a high sensitivity of ~2.32 kPa
⁻¹
at 1 kPa and temperatures with the sensitivity of ~0.64 (%)/(°C) up to 80°C, thus demonstrating high potential for use in robotics and touch based interactive systems.