Ultrasonic‐Assisted Freeze‐Drying for Polyimide/Carboxylated MWCNTs Aerogel Sensor with Excellent Aging Sensing Performance

Abstract Along with the rapid development of science and technology, the new demand for flexible strain sensors have been put forward in the field of aerospace and other sophisticated exploration areas. Meanwhile, the high temperature generated during the launch of the aerospace aircraft presents new challenges. The existing high temperature resistant sensors are limited in further development by their inherent defects (stability, high processing costs, etc.). A flexible strain sensor with high‐temperature sensing capability is urgently needed. Therefore, the composite polyimide aerogel flexible strain sensor is prepared by ultrasonic‐assisted freeze‐drying method and thermal imidization. Characterizing the structure and sensing performance of the polyimide/carboxylated MWCNTs (PI/CNTs) composite aerogel, the tunneling effect is innovatively introduced to theoretically calculate the parameters in the sensing path. The prepared composite sensor has a high sensitivity (5.34), a fast response time (187 ms), and long‐term cycling stability (1000 cycles). The composite aerogel sensor, which has undergone high temperature aging, still has good sensing performance. It can be used for sensing under extreme conditions, for example, the peripheral electronic devices of aerial probes are used to sense and detect external deformation or withstand pressure conditions.