Mechanism Investigation and Structural Design of Hybrid Responses Pressure Sensor 

   Capacitive pressure sensors (CPS) capable of conforming to curvilinear and even deformable surfaces are essential components of e-skins. However, the applications of CPS in soft e-skins have been limited by i) the decay of sensitivity with increasing pressure; ii) the coupled response of in-plane deformation and out-of-plane pressure.

Our lab recently overcame the first major limitation through developing a flexible hybrid response pressure sensor (HRPS). HRPS is constructed by laminating a barely conductive porous nanocomposite (PNC) with an ultrathin insulating layer between two parallel electrodes. The PNC was a carbon nanotube (CNT)-doped Ecoflex composite with an overall porosity of 86%. the PNC exhibits a hybrid response encompassing both piezoresistivity and piezocapacitivity. 

However, there still exist some unclear fundamental questions about how piezoresistivity and piezocapacitivity interact with each other.  Therefore, we are investigating the mechanism of HRPS.  Through the mechanism study, we hope that we can design the structure of HRPS to decouple the response of in-plane deformation and out-of-plane pressure. 

Ongoing project includes: 

-Mechanism study of HRPS: how piezoresistivity and piezocapacitivity change with pressure.

-Structural design of HRPS to decouple response of in-plane deformation and out-of-plane pressure.