High-Performance Sustainable Cellulosic Paper Based on Flame Retardancy Coating with Photothermal Sterilization

Inherent drawbacks of cellulose paper, like flammability and mildew, have become increasing potential issues affecting safety and health in public places. Herein, a universal interface self-assembly strategy is developed for synthesizing the functional composite heterostructure PA/PB-MMT (phytic acid/Prussian blue-montmorillonite). The synergetic combination of the PA surface adhesion and electrostatic interaction enables the realization of PA/PB-MMT-PEI-3 with effectively stable connection, reliable flame retardancy, and excellent photothermal sterilization performance. Moreover, the synergistic effect between P–N and Fe not only leads to a stable improvement in the mechanical properties with the tensile strength increasing to 2.7 ± 0.3 MPa but also leads to PA/PB-MMT-PEI-3 exhibiting fire retardant properties with a limiting oxygen index value of 33.5%. The resultant PA/PB-MMT-PEI-3 shows excellent photothermal conversion performance, resulting in outstanding sterilization efficiency upon near-infrared (NIR) irradiation. This work provides vital guidance in the design of functional materials for integrating fire safety and antibacterial properties in modified paper materials.