Study of capacitance type flexible electronic devices based on polyacrylamide and reduced graphene oxide composite hydrogel

Flexible electronic devices can transform various external stimuli into electrical signals, and have broad prospects in wearable devices, soft machines, artificial intelligence and other fields. However, the flexible electronic materials based on hydrogel lack mechanical strength and stability. Meanwhile, the electrodes in hydrogels are also easily corroded by electrolytes. In this work, the capacitive sensor based on polyacrylamide-rGO (PAM-rGO) composite hydrogel was studied to solve these problems. Due to the effect of hydrogen bonds, the reduced graphene oxide (rGO) can greatly enhance the mechanical strength of hydrogels. At the same time, the hydrogel is encapsulated in the capacitor, and the stability of the capacitor increases due to the decrease of the water loss of the hydrogel. The PAM-rGO composite hydrogel did not contain free anion and cation, the corrosion of the electrode decreased and the service life was prolonged. The wearable device of PAM-rGO composite hydrogel sensor performed well in tensile and compression stimulation tests, and the linear relationship reached 0.998 and 0.992 in turn, showing potential applications in the field of flexible electronic devices.