MXENE-REINFORCED POLYMER NANOCOMPOSITES FOR FLEXIBLE WEARABLE SENSORS AND ELECTROMAGNETIC INTERFERENCE SHIELDING APPLICATIONS

Abstract

Multifunctional nanocomposites made of Ti3C2Tx MXene and thermoplastic polyurethane (TPU) are presented in this research for applications as flexible strain sensors and electromagnetic interference (EMI) shielding material. The synthesis process of Ti₃C₂Tx MXene involves selective etching of Ti₃AlC₂ MAX phase through LiF/HCl, and subsequent delamination. Nanocomposite films containing 0, 2, 5, 10, and 15 wt% MXene content were prepared and analyzed. XRD results confirmed the formation of MXene along with increased interlayer space, while FTIR results showed hydrogen bonding between surface groups of MXene and the TPU backbone. The morphology analysis using SEM and TEM showed accordion-type layered structures and ultrathin nanosheets. Thermal stability was enhanced with an increase in degradation temperature from 287 °C to 315 °C. Electric conductivity varied from 1.8×10−10 S/m in the case of pure TPU to 11.6 S/m in the case of 15 wt% MXene-TPU, with percolation from 5 to 10 wt%. The optimal ratio of MXene-10 yielded a gauge factor of 12.5, response/recovery times of 72/86 ms, and 94.3% response retention for 5000 cycles. Besides, the sensor could monitor human activities. The values of EMI shielding effectiveness varied within 29.6–33.8 dB in the X band and increased from 18.9 to 37.4 dB in the same range of frequencies when thickness changed from 50 to 200 µm. At the same time, 92.1% of shielding efficiency was retained after 1000 bending cycles. The shielding effect was based on conductive loss, interfacial polarization, and multiple internal reflections.