Three-Layer Core-Shell Ag/Agcl/Pedot : Pss Composite Fibers Via a One-Step Single-Nozzle Technique Enabled Skin-Inspired Tactile Sensors

High sensitivity plays a crucial role in the development of wearable electronic devices. For fiber-based wearable sensors, the sensitivity mainly depends on the conductive properties and surface structure of the fibers. Researchers have made great progress in exploring novel structures and sensing mechanisms for flexible sensors so far. However, the development of convenient and rapid methods to prepare conductive fibers with high conductivity and sensitivity still requires unremitting efforts. In this work, PEDOT: PSS fibers were firstly prepared by wet spinning, which were subsequently placed in Tollens' reagent with the addition of hydroxyurea for a specific silver mirror reaction, achieving three-layer core-shell Ag/AgCl/PEDOT: PSS composite fibers with an optimal conductivity up to 5.2×104 S·cm-1. The resultant composite fibers have extremely fast response time (32 ms) and high sensitivity (5.12 kPa-1), while revealing a pressure-dependent feature. It is worth mentioning that the surface of these composite fibers is not a smooth silver layer, but a layer made of tightly stacked Ag nanoparticles, which contribute to a fast response time, ultra-low detection limit, and bidirectional resistance change. Benefiting from the excellent performance, these fibers have been demonstrated to be used as a flexible sensor in wearable e-textiles. Meanwhile, it is expected to be prepared into next-generation flexible electronics such as bionic arms or artificial intelligence