3D wearable piezoresistive sensor with waterproof and antibacterial activity for multimodal smart sensing

High sensitivity, excellent stability and rapid response have been gradually satisfied with the rapid development of 3D wearable piezoresistive sensors. Nevertheless, advanced parameters such as waterproof and antibacterial property, which are critical to wearable electronics, have received inadequate attention. Herein, a 3D wearable piezoresistive sensor with waterproof and antibacterial activity was fabricated with the utilization of graphene, silver nanoparticles (Ag NPs), polyurethane (PU) and thermoplastic polyurethanes (TPU). This 3D TPU@rGO-Ag NPs@PU sensor exhibits competitive sensing performance, achieving a remarkable sensitivity (GF(max)=152.97kPa(-1)), reliable dynamic stability (over 10,000 cycles), fast response/recovery time (50 ms/40 ms), and satisfactory sensitivity retention (similar to 90%). Furthermore, this sensor achieves outstanding waterproof and high antibacterial activity (>99.9%), providing ample convenience for the realization of wearable. Besides, fingering habits, typing strength and typing speed can be captured by this sensor, which overcomes the security deficiencies of password authentication system and improves the security of information. This 3D piezoresistive sensor shows huge potential in multimodal smart sensing, which provides opportunities for developing intelligent wearable sensors and future broad commercial applications.