High-Sensitivity Pressure Sensors Using PPy/MWCNTs/PDMS@Melamine Foam for Human Motion Detection on Land and Underwater

Flexible pressure sensors with high sensitivity and outstanding mechanical reliability are crucial for human motion detection. In this work, we fabricated a flexible pressure sensor with a bilayer conductive structure using PDMS/MWCNTs@polypyrrol@melamine foam (PMPM). Typically, the construction of extra conductive routes is facilitated by a porous structure to achieve a high sensitivity of 117.61 kPa–1 for pressure in a low detection limit and constant gauge factor (GF) of 6.39 over a linear compression strain range. Furthermore, the polypyrrole particles covering the surface of melamine foam could enhance electron transfer and spatial deformation. And such hierarchical structures can form highly interconnected conductive networks, providing sensitive sensing behavior for a pressure range from 0 to 100 kPa and a strain range from 0 to 60%. Moreover, the PMPM sensor presents superhydrophobicity (CA > 150°) and excellent reliability (∼1200 cycles). The PMPM sensors show good sensing performance in detecting typical human movements, such as bending of joints. The motion detection of human motion underwater without encapsulation is also realized. This work may provide an innovative scheme for accessing the next generation of health and sports monitoring electronics.