Investigations on Different Sol-gel Incorporation Methods of Green Synthesized AgNPs in Textiles for Antibacterial Activity

Sol-gel is an excellent antibacterial agent carrier. Different researchers incorporated various antibacterial substances, including silver nitrate (AgNO3), quarternary ammonium chloride (QAC), and titanium dioxide (TiO2) in sol-gel. However, there is limited study on the influence of pH and acid hydrolysis time (ageing) to form sol-gel. Besides, few investigations have been made on the influence of fabric structure and silver nanoparticles (AgNPs) incorporation into fabrics by the sol-gel method. This study also compared the light and heavy fabrics in terms of sol-gel application and the advantages of sol-gel over other AgNPs incorporation methods. The sol-gel-AgNPs incorporated fabric samples were characterized by Ultra Violet Spectroscopy (UV-VIS), X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersion spectroscopy (EDS). For AgNPs synthesis in a green way, we used Calendula arvensis, a Mediterranean weed. This study found, that for sol-gel formation the minimum acid hydrolysis time was 5.30 hours, 6.30 hours, and 8.00 hours at 60 ºC, 25 ºC, and 3 ºC, respectively. After ageing, a minuscule amount of alkaline was needed for gelation. Seven different methods for incorporating AgNPs through sol-gel have been illustrated. The lower molarity of AgNO3, having a more significant portion in the sol-gel solution, had excellent antibacterial activity and wash fastness. Besides, the ex-situ method was better than the in-situ method. Among different types of cotton fabric, lightweight knit fabric showed much better antibacterial activity than heavier twill fabric.