Structural health monitoring for polymer composites with surface printed MXene/ink sensitive sensors

In this study, a novel sensor with high sensitivity and linear was prepared based on two-dimensional (2D) material (MXene) and ink, which can be used for deformation and damage monitoring of structural composites. The MXene was efficiently prepared by etching Ti3AlC2 powder with LiF–HCl solution and subsequent vacuum drying. The viscosity and adhesion of MXene/ink composites were controlled by changing the ratio of solvent (dimethyl sulfoxide) to ink. The MXene/ink was printed on the surface of the composite material to avoid forming defects in the composite material. The percolation threshold of the MXene/ink nanocomposite was relatively low, 3.6wt%. In this paper, MXene/ink composites with different contents were selected as the sensor, and the characteristics of the sensor were verified through monotone stretch and cyclic load-and-unload tests. When the MXene content just exceeds the percolation threshold (4wt%), the gauge factor (GF) of the sensor is higher, the results of monotonic tensile experiment show that there are two different sensitive stages of linear change (0 ~ 0.477%) and (0.477 ~ 1.37%), and the range GF is116.6 and 554.3, respectively. In addition, the linear relationship and sensitivity of the sensor remained stable after loading and unloading tensile tests. MXene/ink sensor has a broad application prospect in damage monitoring of aerospace structural composites.