Long-term Study of Cu/SiO2 Microspheres as Antimicrobial Additives in Paints

Abstract

Cu/SiO2 microspheres were prepared with the sol-gel process by adding 3-(glycidyloxypropyl)trimethoxysilane (GLYMO), using tetraethoxysilane (TEOS) as a silica precursor. Sol-gel formation with acid catalysts and copper acetate monohydrate was used in combination with a spray dryer, to obtain Cu/SiO2 microspheres. SEM-EDS showed the surface morphology, the particle size, and the shape of the Cu/SiO2 microspheres. The long-term effects of Cu/SiO2 microspheres against microorganisms in paint were determined using the fungus (P. funiculosum), gram-negative bacteria (E. coli), and gram-positive bacteria (S. aureus). The addition of GLYMO increased the stability of antimicrobial properties by lengthening the biocidal effect up to 12 months with 85% inhibition, in comparison with the commercial antimicrobial paint, which showed only 40% inhibition in the same time period.