Surface-engineered porous MXene-elastomer composites-based ultra-sensitive pressure sensor assembled via electrostatic interaction for human-machine interface

Flexible and wearable devices require high-performance pressure sensors for human motion monitoring, but conventional sensors have limited deformability and complex fabrication. To overcome these issues, a composite structure incorporating conductive nanomaterials and a deformable elastomer has been proposed. However, an inherently weak adhesion between the elastomer and nanomaterials remains a practical challenge. To address this, we show a porous polymer sponge coated with Ti₃C₂T_x MXene as an ultra-sensitive pressure sensor. The sensor is fabricated by creating a deformable elastomer sponge using a sugar template, followed by a simple dip-coating process to apply MXene nanosheets. The elastomer surface is chemically treated using surfactants to enhance the surface energy and induce electrostatic forces, thereby improving adhesion between the elastomer and MXene while maintaining the intrinsic mechanical properties of the elastomer. This stable MXene-based network ensures high sensitivity across a broad pressure range. The sensor's low stiffness and porous structure enable rapid response to subtle pressures like breathing and gentle touch, as well as larger forces like arm bending and foot pressure. When integrated into a human-machine interface for the walking assistive device, the pressure sensors enable active control of the exoskeleton, facilitating easier joint motion for rehabilitation.