Flexible Silica/MXene/Natural rubber film strain sensors with island chain structure for Healthcare monitoring

The demand for flexible strain sensors with high sensitivity and durability has increased significantly. However, traditional sensors are limited in terms of their detection ranges and fabrications. In this work, a space stacking method was proposed to fabricate natural rubber (NR)/ Ti₃C₂T_x (MXene)/silica (SiO₂) films that possessed exceptional electrical conductivity, sensitivity and reliability. The introduction of SiO₂ into the NR/MXene composite enabled the construction of an “island-chain structure”, which promoted the formation of conductive pathways and significantly improved the conductivity of the composite. Specifically, the electrical conductivity of the NR/MXene/10 wt%SiO₂ composite was enhanced by about 200 times compared to that of the NR/MXene composite alone (from 0.07 to 13.4 S/m). Additionally, the “island-chain structure” further enhanced the sensing properties of the NR/MXene/10 wt%SiO₂ composite, as evidenced by its excellent sensitivity (GF = 189.2), rapid response time (102 ms), and good repeatability over 10,000 cycles. The fabricated device demonstrates an outstanding mechanical sensing performance and can accurately detect human physiological signals. Specifically, the device serves as a strain detector, recognizing different strain signals by monitoring the movement of fingers, arms, and thighs. This study provides critical insights into composite manufacturing with exceptional conductivity, flexibility and stability, which are essential properties for creating high-performance flexible sensors.