Silver nanoparticles nucleated in NaOH treated halloysite: a potential antimicrobial material

Despite all recent advances in medical treatments, infectious diseases remain dangerous. This scenario has led to intense scientific research on materials with antimicrobial properties. Silver nanoparticles (Ag-NPs) are a well established solution in this area. The present work studied the nucleation of silver in halloysite substrates (HNT) modified by a NaOH chemical treatment. The resulting stabilized Ag-NPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDS). The nucleation was characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Ag-NPs antimicrobial properties were investigated against \textit{E. coli} and \textit{S. aureus}. The potential of Ag-NPs for industrial application was tested by dispersing them into low density polyethylene (LDPE). The importance of the chemical affinity between matrix and additive was tested coating Ag-NPs with dodecanethiol, a non-polar surfactant. The resulting composites were characterized by scanning electron microscopy (SEM) and in terms of surface antimicrobial activity. The results demonstrate that Ag-NPs synthesized in this work are indeed antimicrobial, and that it is possible to imbue a polymeric matrix with the Ag-NPs antimicrobial properties.