The present disclosure describes a method for preparing a paper nanocomposite, including: continuously providing a first suspension that includes lignocellulosic pulp fibers, cellulose nanofibrils, carbon nanotubes, and a cationic surfactant; continuously adding a second suspension to the first suspension to provide a slurry, the second suspension includes lignocellulosic pulp fibers, cellulose nanofibrils, carbon nanotubes, and an anionic surfactant; depositing the slurry comprising the first and second suspensions onto the substrate; and dewatering the slurry to form the paper nanocomposite.