Wearable and flexible bacterial cellulose/polyaniline ammonia sensor based on a synergistic doping strategy

• First-time provided a synergistic doping strategy for higher interchain and intrachain carrier mobility of PANI. • The first-time introduction of the 3D interconnected dual network for flexible wearable ammonia sensor. • The sensing mechanism of co-doping PANI to enhance ammonia sensing is deduced in detail. • The detection limit of the sensor is less than 10 ppb to ammonia at room temperature. Herein, using three-dimensional interconnected bacterial cellulose (BC) as substrate, we prepare a wearable polyaniline (PANI)-based ammonia sensor via co-doping method with sulfosalicylic acid (SSA) and poly(2-acrylamido-2-methyl-1-propane sulfonic acid) (PAMPS). The introduction of SSA is intended to improve the intrachain carrier mobility of PANI, while the simultaneous doping of PAMPS is responsible for efficient interchain charge transfer, resulting in a significant synergy in carrier mobility and sensitivity enhancements. Moreover, with high specific surface area and 3D network, BC substrate is beneficial to enhance the contact area with detected gas as well as the mechanical tolerance during the practical utilization. Consequently, our PANI-SSA/PAMPS-based sensor performs a high response (21.3 for 50 ppm ammonia), quick response and recovery time (4.1 s/16 s). Furthermore, the sensor also demonstrates excellent ammonia selectivity among different interfering agents, with a lower detection limit (LOD) of 10 ppb at room temperature, and the limit sensing temperature even below -10 °C. Our work provides more opportunities for the design of flexible gas sensor in sensing application.