Lifetime health monitoring of fiber reinforced composites using highly flexible and sensitive MXene/CNT film sensor

In this paper, lifetime health monitoring of composites was conducted, included manufactured monitoring and structural health monitoring. A thin film sensor composed of multi-walled carbon nanotubes (MWCNTs) and MXene was developed through simple mixing and spray vacuum filtration. This highly flexible and susceptible MXene/CNT film sensor can be embedded in polymer composites to monitor the phase change of the resin and the determination of the gel point during the preparation of the composite in real-time. The MXene/CNT film sensors were embedded and arrayed in fiber-reinforced composites, which can be used for resin curing monitoring, then continued structural health monitoring. Experimental results show that the MXene/CNT film sensor embedded in the composite laminates can effectively capture the change of the resin phase, that characterized by resistance. MXene/CNT films have a good ability to respond to changes in the resin state. The gel point of resin obtained from the MXene/CNT film sensor is 134 °C, which is consistent with 137 °C from the DMA results. The accurate gel point can optimize the curing system and improve the quality of composite products. Then the tensile, bending, and fatigue tests of fiber-reinforced composite laminates embedded with MXene/CNT film sensors were carried out. MXene/CNT film sensor can keep good response and response consistency for a long time. As a novel sensor, the MXene/CNT film sensor has the advantages of high response sensitivity, solid real-time performance, and long service time. The MXene/CNT film sensor has great potential to establish and optimize manufacturing processes and to improve the cure quality of fiber-based resin composites. This sensor can be used to follow the entire life cycle of a composite from fabrication till end-of-life.