In situ doping enables the multifunctionalization of templately synthesized polyaniline@cellulose nanocomposites

•In situ oxidative polymerization of polyaniline on bacterial cellulose template.•In situ doping imparts PANI@BC aerogel excellent flame retardance and conductivity.•PANI@BC hydrogel exhibited self-motion behavior under low voltage electric field. Cellulose aerogels have been widely studied as promising environmentally friendly materials due to their low density, biocompatibility and degradability. However, their applications are limited due to their highly combustible nature. In this study, polyaniline (PANI) decorated bacterial cellulose (BC) composite aerogel has been synthesized with in situ polymerization of aniline monomer on the surface of BC scaffold. The PANI decorated BC composite aerogel has a very high specific area of 124.0m2/g and well-preserved nanoporous structure, while its conductivity drastically increased to 10.44S/m. Interestingly, phosphate groups were incorporated onto PANI backbones due to its unique doping/dedoping structure. The resultant composite aerogel presented excellent flame retardancy, which can be self-extinguished within 1s. Moreover, PANI@BC composite hydrogel exhibited self-motion behavior under low voltage electric field, illustrating potential electromechanical actuator application. This simple and sustainable in situ doping method opens up new opportunities for cost-efficient fabrication of multifunctional cellulose-based electronics.