Highly stretchable, breathable and negative resistance variation textile strain sensor with excellent mechanical stability for wearable electronics

In recent years, wearable and stretchable electronic devices have attracted great research interest and effort due to their promising applications in electronic skin, wearable health monitoring, human-machine interactions and so on. However, it still remains a great challenge to fabricate highly stretchable and wearable devices with excellent breathability, mechanical robustness and laundering durability. Herein, we fabricated a highly stretchable and breathable textile strain sensor based on conductive polyester fabric (CPF) with weft-knitted structure by chemically growing conductive and transparent Al-doped ZnO (AZO) element via atomic layer deposition (ALD). The CPF strain sensor demonstrates captivating performance, including high stretchability (up to 130%) and long-term stability (3000 cycles), as well as a distinct negative resistance variation with increasing strain owing to its weft-knitted structure. Most importantly, due to the formation of chemical interactions between textiles and AZO films during ALD process, the CPF strain sensor exhibits excellent mechanical robustness and laundering durability under reciprocating rubbing (50 kPa load pressure, 30 cycles), washing (500 r/min for 10 cycles, 200 min) and light fastness (accelerated light aging test for 7 days), thus allowing the fabrication of breathable and comfortable wearable sensor without elastomer encapsulation. Based on its admirable performances, the CPF strain sensor can be easily knitted or sewed on garments or attached on human skin directly for tracking both large and subtle human motions, revealing its numerous prospects in wearable electronics, intelligent robotics and other fields.