Wearable, Ultrawide-Range, and Bending-Insensitive Pressure Sensor based on Carbon Nanotube Network-Coated Porous Elastomer Sponges for Human Interface and Healthcare Devices.

Flexible and wearable pressure sensors have attracted tremendous attention due to their wider applications such as human-interfacing and healthcare monitoring. However, it is a great challenge to achieve accurate pressure detection and stability against external stimuli (in particular, bending deformation) over a wide range of pressure from tactile to body weight levels. Here, we introduce an ultrawide-range, bending-insensitive, and flexible pressure sensor based on a carbon nanotube (CNT) network-coated thin porous elastomer sponge for use in human interface devices. The integration of the CNT networks into three dimensional (3D) microporous elastomers provides high deformability and a large change of contact between the conductive CNT networks due to the presence of micropores, thereby improving the sensitivity compared with that obtained using CNTs-embedded solid elastomers. As electrical pathways are continuously generated up to high compressive strain (~80%), the pressure sensor shows an ultrawide pressure-sensing range (10 Pa-1.2 MPa) while maintaining favorable sensitivity (0.01-0.02 kPa) and linearity (R ~0.98). Also, the pressure sensor exhibits excellent electromechanical stability and insensitivity to bending-induced deformations. Finally, we demonstrate that the pressure sensor can be applied in a flexible piano pad as an entertainment human interface device and a flexible foot insole as a wearable healthcare and gait monitoring device, respectively.