Bactericidal activity of coatings with nanomaterials obtained by green chemistry

ELENA RASTELLI; ERASMO GÁMEZ ESPINOSA; NATALIA BELLOTTI; CECILIA DEYÁ; MARISA VIERA ; SANDRA GÓMEZ DE SARAVIA

Congreso; XXI Congreso Internacional de Metalurgia y Materiales CONAMET-SAM y en el XV Congreso Iberoamericano de Metalurgia y Materiales IBEROMAT.; 2023

In addition to their decorative function, paints are used to protect surfaces from oxidation, from adverseeffects of weather and the sun, as well as from biofilm formation. The increasing demand for newantimicrobial paints is rising due to the important need to avoid the spreading of infections mainly causedby harmful microorganisms [1]. Nano-based antibacterial agents are gaining wide acceptance by scientificexperts all over the world for their antimicrobial effects [2]. Nanoparticles (NPs) are usually synthesizedthrough physical and chemical methods such as laser ablation, sol-gel and electro-explosion. However, thesetechniques have proven to pose health and environmental hazards. For this reason, it is crucial to adapt saferoptions for their fabrication. With this, the concept of “green nanoparticles” is developed which is essentiallythe synthesis of nanoparticles using environmentally benign routes [3]. Considering the above, and knowingthe bactericidal action of silver (Ag), the objective of this work was to obtain silver nanoparticles (AgNPs)by green synthesis technique to be incorporated into a potential water-based hygienic paint. AgNPs wereobtained by adding Schinopsis balansae (TS) or Caesalpinia spinosa (TC) tannin solution in an aqueoussolution of AgNO3, stirred for 30 minutes at 60 °C with pH adjusted to 7. The concentration of the TS orTC solution was 500 ppm. The final concentration of AgNO3 in each synthesis system was 10-2 M. TheNPs were purified by successive washes using a microcentrifuge (15000 rpm, 20 min, 20 °C). The particlesin suspension were kept in the fridge at 4 °C in caramel flasks [4]. The AgNPs were characterized by UVVis and FTIR spectroscopy, TEM, SEM and EDS. To carry out the tests, a water-based paint was formulatedand prepared with 13.78 g of distilled water, 42.09 g of resin, 12.4 g of TiO2, 27.32 g of natural CaCO3,2.43 g of precipitated CaCO3 and 1.98 g of additives, mixed in a high-speed disperser. For the treatmentpaints (AgNPs-TS paint and Ag-NPsTC paint), all the water was replaced by the corresponding suspensionwith the nanoparticles, obtaining a concentration of 13.78 mg Ag /100 g of paint.