A general strategy to immobilize metal nanoparticles on MXene composite fabrics for enhanced sensing performance and endowed multifunctionality

Multifunctional flexible pressure sensors with high sensitivity and a wide sensing range can meet the requirements of various complex applications. Herein, metal (Au or Ag) nanoparticles (NPs) are introduced onto a MXene-coated nonwoven fabric (MNWF) using a self-reduction strategy to build a "brick-mortar" hierarchical structure (AuNPs or AgNPs@MNWF). This method is green and environmentally friendly because the self-reduction properties of MXene endow noble metal NPs with uniform sizes and controlled densities to be introduced without using reducing agents or surfactants. The introduction of metal NPs and the construction of composites considerably improve the piezoresistive properties of MNWF, resulting in a 4-fold increase in sensor sensitivity (a linear sensitivity of 24.5 kPa −1 at 0-100 kPa). Moreover, the excellent electrical conductivity and unique plasmonic effect of metal NPs also contribute toward enhancing the heating performance and expanding the antibacterial applications of MNWF. In particular, compared to MNWF, AgNPs@MNWF as a dual energy-driven flexible wearable heater exhibits an electrothermal enhancement of 25.3 °C (at 7.5 V) and a photothermal enhancement of 5.6 °C (at 100 mW cm −2 ). Notably, the antibacterial efficiency of AgNPs@MNWF is as high as 99.9%, indicating the potential of this material for applications in the medical and health field, such as in intelligent mattresses. Overall, noble metal NPs can enhance the sensing performance as well as the Joule heating, and photothermal and antibacterial properties of MNWF. Thus, this work extends the applicability of the self-reduction strategy, providing a general strategy for expanding the applications of multifunctional fabric-based flexible sensors. A general strategy was developed to enhance the sensing performance of MNWF composites and realize multifunctional applications by introducing metal NPs.