Flexible polyaniline-coated poplar fiber composite membranes with effective electromagnetic shielding performance

Chemical pretreatment combined with ultrasonication was employed to obtain uniform cellulose nanofibers from poplar wood, which were then used for the fabrication of a flexible cellulose nanofiber/polyaniline (CNF/PANI) membrane with core-shell heterostructure by in-situ polymerization. In sharp contrast to the hydrophilic cellulosic material, the composite membrane was very stable in water. The as-prepared nanocomposite membranes, particularly those with 50% PANI-coated nanocomposites, exhibited high electromagnetic interference (EMI) shielding effectiveness (SE) of up to 25.2 dB (with thickness of only 0.28 mm). The experimental results indicated that microwave absorption was the main shielding mechanism of the membranes. The special chemical treatment combined with ultrasonication endowed the CNF surface with more hydroxyl and carboxyl groups, which facilitated the PANI loading. The enhanced SE of membrane was attributed to the core-shell heterostructure and the porous structure provided by the cellulose nanofibers.