High-strength Janus cellulose/MXene composite paper from deep eutectic solvent-carboxymethylated eucalyptus fibers...

The development of cellulose-based electromagnetic shielding materials is critical for the advancement of sustainable, lightweight, and flexible electronic devices. Most high-performance composites rely on nanocellulose, which is expensive and energy-intensive to produce. In this work, we employ chemically modified conventional eucalyptus pulp fibers (non-nano) to fabricate Janus-structured cellulose/MXene composite papers. A deep eutectic solvent (DES) composed of benzyltriethylammonium chloride and formic acid is used to produce the fibers, enhancing their chemical accessibility and swelling. Subsequent carboxymethylation promotes dense inter-fiber hydrogen bonding, forming a mechanically robust substrate for vacuum-filtered MXene deposition. The resulting Janus paper displays distinct functional layers, combining high strength and excellent conductivity. At 40 wt% MXene, the composite achieves a tensile strength of 118.12 MPa, electrical conductivity of 245.04 S/m, and EMI shielding effectiveness exceeding 45 dB. It also exhibits rapid Joule heating and photothermal conversion performance. Overall, this work provides a sustainable strategy for developing multifunctional, high-performance paper-based materials, demonstrating that conventional pulp fibers can rival nanomaterials in advanced electronic applications.