Simple and environmentally friendly approach for preparing high-performance polyimide precursor hydrogel with fully aromatic structures for strain sensor

Abstract The development of wearable devices, soft robots, and electronic skin requires strain sensors that integrate multiple functionalities, such as being stretchable, self-healing, and biocompatible. In this work, we prepared a fully aromatic polyamic acid salt (PAAs) hydrogel using a novel and simple approach. This study describes an environmentally friendly and green synthetic method for synthesizing. The obtained PAAs hydrogel exhibits excellent stretch ability and has an elongation rate of about 1350%. It can also rapidly complete self-healing and return to the original mechanical strength without needing any external stimuli. In addition, the PAAs hydrogel has excellent temperature responsiveness. When used as a strain sensor, the PAAs hydrogel has a sensitive electrical resistance response even after 200 cycles and adhesiveness to various surfaces, especially human skin. To the best of our knowledge, this is the first time to prepare a high-performance polyimide (PI) precursor hydrogel that can be used as a raw material for PI aerogel. Because of its superb overall performance, low preparation cost, efficient preparation, and environmentally friendliness, the PAAs hydrogel is highly suitable for use as sensitive strain sensors for applications in motion detection.