Temperature-Dependent Fatigue Properties of MXene-Based Flexible Pressure Sensor with Hollow Structure

The sensing capability of flexible piezoresistive sensors made of polymers and nanofillers can be significantly improved by a hollow design, with their mechanical stability being closely linked to temperature variations. In this article, a flexible piezoresistive sensor based on hollow polydimethylsiloxane (PDMS)/MXene/carbon nanotube active layers is fabricated using a sacrificial template method. It is observed that the sensitivity of the sensor is attenuated down to 8% as the temperature falls from 20 to −40 °C during bending 10,000 times. The numerical results and theoretical analysis indicate that reduced strain energy absorption by PDMS and weakened geometric confinement of the hollow skeleton at low temperatures jointly accelerate the disruption of van der Waals interactions at the PDMS/MXene interface, constituting the main cause of this phenomenon. The interfacial energy dissipation behavior of PDMS can effectively alleviate van der Waals force damage and protect the integrity of the hollow skeleton at 20 °C. However, under subzero temperatures, the PDMS chains cannot effectively disperse strain energy, and this results in damage to the hollow structure, ultimately deteriorating the sensor’s fatigue endurance. This work may provide new insights for the development of flexible electronics with antifatigue performance in harsh environments.