Implanting Ag nanoparticles in SiOC ceramic nanospheres for exceptional electromagnetic wave absorption and antibacterial performance

The development of multifunctional composites with desirable electromagnetic wave absorption and antibacterial performance for the medical field has aroused wide interest. In this work, SiOC/Ag composites were successfully fabricated via the liquid-phase method. When the filler content of SiOC/Ag-3 is 40 wt%, SiOC/Ag-3 exhibits excellent electromagnetic wave absorption performance, achieving a minimum reflection loss (RL_min) value of −58.03 dB with a matching thickness of only 2.82 mm. The superior electromagnetic wave absorption performance is attributed to (i) multiple reflections, (ii) conductive loss, and (iii) interfacial polarization loss. In addition, the radar cross-section (RCS) simulation indicates that all RCS values of the perfect electric conductor (PEC) with the SiOC/Ag-3 coating are below −20 dB·m² across the incident angle range from −60° to 60°, indicating strong radar stealth performance. Moreover, SiOC/Ag composites also achieve excellent antibacterial ability against E. coli and S. aureus through the generation of reactive oxygen species (ROS) under visible light irradiation. This work provides new insights into the design and development of bifunctional composites with electromagnetic wave absorption and antibacterial performance for application in medical devices.