Conductive Nanocellulose Enabling Flexible, Sensitive and Robust Fiber Sensor for Multiple Signals Monitoring

Wearable electronics based on natural biocompatible fibers have attracted considerable interests due to the promising use for healthcare monitoring, human–machine interactions, and smart clothing. However, crucial challenges to design robust, flexible, and highly sensitive fiber sensors remain, to meet various requirements for practical application. Herein, Fischer esterification and in situ polymerization technologies were employed to produce conductive nanocelluloses (CNC–PEDOT), which possessed excellent mechanical stiffness and high conductivity (238 μS/cm). Then, silk yarns as supporting materials were functionalized by as-prepared conductive units to construct all-in-one fiber sensor (SCP) for multiple signals monitoring. Surprisingly, the resulted SCP fiber showed impressive mechanical performances (422.86 MPa at 18.44%), due to the strong hydrogen-bond interaction between SY substrate and CNC–PEDOT conductive units. More importantly, SCP fiber was employed a dual-function sensor for real-time monitoring of strain and temperature, illustrating remarkable sensitivities, i.e., gauge factor = 4.28 in a large strain range of 0–16%, and sensitivity = 1.55%/℃ in a broad temperature range of 25–60 ℃. The SCP fiber sensor with impressive mechanical performances and high sensitivity, can be applied for real-time health monitoring in wearable biosensors, smart healthcare, and on-demand therapy.