Fungal deterioration control in outdoor environments by nano-additivated waterborne paint

GAMEZ ERASMO; DEYA CECILIA; BELLOTTI NATALIA

Congreso; XXV Congreso Latinoamericano de microbiología; 2021

Asociación de bioquímicos del Paraguay

Biodeterioration of facades in building constructions causes economic losses. Filamentous fungi by their presence cause aesthetic damage to structural materials. In addition, its invasive growth through hyphae generates physical deterioration and due to its nutrition and excretion, they release enzymes, acids and pigments that cause chemical deterioration. To control fungal deterioration, paint additives with nanostructured biocides can be applied on facades. In addition, it is important that the nanoadditive maintains its long-term antimicrobial activity to delay fungal deterioration. The aim of this research was to assess the antifungal activity of a waterborne paint additivated with ZnO nanoparticles (ZnONPs) after 4 years exposed to the outdoor environment.Control paint without biocides (PC), was prepared. Following the same base formulation, paints additivated with the ZnONPs were prepared replacing 1%, by weight, the natural calcium carbonate by the corresponding NPs (PZnO). The nanoparticles were supplied courtesy of Dr. Facundo Ruiz, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México. Paints films applied on pretreated concrete were exposed to the natural weather conditions of La Plata city (34º54?S and 57º55?W) (Fig 1). Biodeterioration observed on the coatings was evaluated taking into account ASTM D 5590 standard. The mycobiota of the samples was studied after 4 years of exposition to the outdoor environment. The paints were swabbed and the fungi were isolated following conventional microbiological techniques. In addition, relative density (RD) and apparition relative frequency (RF) of the isolate were calculated. In this study, it was possible to formulate a waterborne paint containing ZnPNOs as additive to control the biodegradation of facades and can be used to prevent fungal deterioration in hospitals and buildings.