A Flexible Leather-Based Sensor via the Dual In Situ Growth of Conductive Materials for Human Motion Detection

Natural leather, with its mechanical strength, flexibility, and wearing comfort, is an ideal substrate material for wearable sensors. Currently, leather-based piezoresistive sensors still suffer from poor uniformity of conductive networks and weak interfacial interactions between conductive materials and leather, which limit their performance. Herein, it was innovatively proposed that polypyrrole (PPy) and silver nanoparticles (AgNPs) were sequentially grown in situ on the surface of collagen fibers (CFs). Then, the tanning process was carried out to produce a leather-based flexible wearable sensor (PPy/AgNPs-LBPS) with excellent conductivity, hydrothermal, and environmental stability. Specifically, the dual in situ growth and tanning process ensured the uniform penetration and distribution of conductive materials in leather substrates. Meanwhile, the hydrogen bonds between the conductive materials and CFs provided a firm combination to prevent the dropping of conductive materials. The synergistic effect of PPy and AgNPs enhanced the sensing performance of PPy/AgNPs-LBPS. It exhibited high sensitivity (0.65 kPa^-1 and 3.76), a wide detection range (0-80 kPa and 0-100%), and fast response capability. These characteristics enabled PPy/AgNPs-LBPS to monitor subtle activities and large-scale movements of the human body in real time, as well as tactile perception. This thesis provides a new idea for the intelligent design of traditional leather materials, multidimensional perception in electronic skin, and advancements in artificial intelligence.