Highly sensitive and flexible wearable pressure sensor with dielectric elastomer and carbon nanotube electrodes

Wearable sensors for tracking human body motion are being increasingly applied in medical systems and are considered important components of human-machine interfaces. This study proposes a flexible sandwich-like capacitive pressure sensor that consists of carbon nanotube-polydimethylsiloxane (CNT-PDMS) composite electrodes and a porous polymer dielectric layer. CNT yarn and polymer materials help fabricate a pressure sensor without complex patterns, easily and quickly. The dielectric layer is made of a porous polymer to improve the sensor sensitivity. The high porosity of the dielectric layer increases its deformation under pressure and enhances the sensitivity (to approximately 5.6 kPa(-1) (%)) even under low pressures (< 5 kPa). The sensitivity of the sensor varies according to the density of porosity and dielectric permittivity of the dielectric layer. Owing to the high porosity of the dielectric layer and flexibility of the CNT yarn, the capacitive pressure sensor proposed in this study exhibits good performance in detecting even a slight change in stimulus. The proposed pressure sensor can be applied in wearable applications such as human-friendly interfaces and sensitive electronic skins. (C) 2020 Published by Elsevier B.V.