Effect of Temperature on Mechanical Fatigue of Flexible Pressure Sensor Based on PDMS-GO Elastomer Composites Embedded With Ag Nanoparticles

Polymer-nanoparticles (NPs) composites are widely used for flexible pressure sensors owing to ease preparation, good conductivity, and flexibility. However, little research focuses on the bending failure mechanism for such sensors under variable temperatures. Here, we study the temperature-dependent bending fatigue of the polydimethylsiloxane (PDMS)/graphene oxide (GO)/Ag NPs pressure sensor. The sensitivity remains similar to 60% after 20 000 bending cycles at 20 degrees C. The retention of the sensitivity after 20 000 times decreases significantly when the temperature changes from 20 to either -40 degrees C or 100 degrees C. The finite element analysis results suggest that the hydrogen bond at PDMS/GO interface and the synergistic effect between GO and Ag NPs dominantly influence the fatigue process at different temperatures. At 20 degrees C, the crack growth is decelerated by hydrogen bond and the resistance of composite remains stable owing to the synergistic effect. However, the hydrogen bond is weakened from 20 degrees C to -100 degrees C, accelerating the crack growth. The strain energy stored by PDMS decreases with decreasing temperature from 20 degrees C to -40 degrees C, which accelerates the crack propagation. These two factors both weaken the synergistic effect, and the sensor thus exhibits a bad fatigue performance at high-/low-temperature conditions.