Investigation of the Shape Mechanism of Green Synthesized Silver Nanoparticles on Cotton Fabrics

Abstract

Silver nanoparticles (AgNPs) can be of various shapes such as spherical, nanorod, cylindrical, cubic, irregular, etc on textile materials. However, there is a huge scarcity of literature on the mechanisms of different shapes of AgNPs. In this study, 3 sets of fabric samples were prepared by pretreating with sodium hydroxide (NaOH), citric acid, and non-ionic detergent (span-80). To investigate the diverse shape mechanism green synthesized AgNPs by Calendula arvensis leaves, Citrus reticulate peel, and Cucumis sativus peel extracts were incorporated into the fabric samples. The samples were characterized by UV-VIS Spectroscopy, X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). The UV-VIS spectra confirmed successful AgNP synthesis for Calendula arvensis and Citrus reticulata, but Cucumis sativus failed AgNP synthesis. The AgNPs were incorporated into the treated fabrics by padding and in-situ method. Then the SEM and XRD images were analyzed meticulously to delve into the nanoparticle shape-building mechanism in light of pH, incorporation methods, and crystallography. It was seen, that pH was the core factor in shape diversity. A pH lower than 7.0 produced predominately closed-pack crystals (111) and due to the low pH, the Gibbs free energy (GFE) was weaker and hence resulted in spherical nanoparticles. Again, the pH range from 7.1 to 8.0 produced cubic shapes due to a high number of open-pack crystals (110) and moderate Gibbs free energy (GFE). On the other hand, pH greater than 8.0 provided high Gibbs free energy, which expedited the reaction and led the nanoparticle shapes to anisotropy.