Antifungal performance of ZnO films on cement-based materials under different application methods and light activation

Fungal growth on concrete threatens both structural integrity and occupant health, particularly in humid environments. This study investigates the antifungal performance of zinc oxide (ZnO) films applied to concrete using two methods: direct application to the sample surface and transfer from formwork of ZnO dispersed in a surfactant solution. We assessed ZnO retention, film uniformity, and antifungal activity against Fusarium oxysporum , Alternaria alternata , and Trichoderma koningii under dark and visible light conditions. The results demonstrate that ZnO-treated surfaces significantly reduce fungal viability, with visible light further enhancing antifungal performance through photocatalysis. Quantitative analysis revealed that ZnO-treated surfaces reduced the number of viable fungal cells by up to 68.4% (0.5 log 10 reduction for Fusarium oxysporum ), 80.1% (0.7 log 10 for Alternaria alternata ), and 74.9% (corresponding to 63,100 viable cells for Trichoderma koningii ) under dark conditions, with even higher reductions of up to 96% observed under visible-light exposure (40 J·cm − 2 ). A dose-response relationship was observed, and similar antifungal efficacy was achieved regardless of the ZnO synthesis route. Surfactant-assisted ZnO films showed better uniformity and coverage. Despite minor issues such as agglomeration and faster surface drying, the brush-based application method is suitable for on-site use. These findings support ZnO as a scalable, low-cost antifungal additive for improving the hygiene and durability of concrete structures.