Preparation of multifunctional ceramic foams for sound absorption, waterproofing, and antibacterial applications.

Using porous materials for sound absorption is an effective approach to alleviating noise pollution, although their hydrophilic properties potentially cause concerns regarding public safety and health risks. This work provides a facile strategy for establishing a multifunctional ceramic system by using sponges as the sintering template, adjusting the pore structure of ceramic foams by varying the ceramic slurry weights and fluorinating the sintered ceramic foams via hydrolysis and condensation processes to provide low surface energy. The obtained porous ceramic foams demonstrate sound-absorbing, waterproof, and antibacterial properties. The results reveal that the increase in ceramic slurry weight decreases the pore size and porosity due to the formation of more compact structures, and the decrease in porosity compromises the sound absorption performance. In the middle-range sound frequency, the maximum sound absorption coefficient reached 0.92. In addition, the fluorination of the rough ceramic surfaces endows the ceramic foams with waterproof properties, which enables them to float on water and display the silver mirror phenomenon. In addition, due to the waterproof property reducing the contact area between the ceramic surface and the bacterial suspension, as well as the lipophilic fluorine chain disrupting the bacterial structures, these ceramic foams exhibited antibacterial rates above 95%. In addition, the mechanisms underlying the sound-absorbing, waterproof, and antibacterial properties of these porous ceramic foams are elucidated. Therefore, this work provides a facile approach to developing a multifunctional ceramic system. Their practical features make these ceramic foams more significant in the field of noise reduction.