Polypyrrole/Ag/mesoporous silica nanocomposite particles: Design by photopolymerization in aqueous medium and antibacterial activity

Abstract

Abstract Ternary nanocomposites of mesoporous silica (SBA-15), polypyrrole (PPy) and silver nanoparticles (Ag NPs) were prepared through a simple method consisting in oxidative photopolymerization of pyrrole in aqueous medium, in the presence of aminosilanized SBA-15 and using AgNO3 as a photosensitizer. The nanocomposites and their precursors were characterized by attenuated total reflexion spectroscopy (ATR), X-ray diffraction (XRD), N2 adsorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). PPy/Ag nanocomposites were loaded in the mesopores and at the surface of SBA-15. The surface composition is PPy-rich and Ag NPs are well dispersed and in the metallic state. The ternary nanocomposites have a high surface area of 201 m²/g. Petri dishes were loaded with various amounts of nanocomposite particles in order to assess their antibacterial effects against E. coli. Strong bacteriostatic effect of PPy/Ag/NH2-SBA-15 was achieved for ternary particle concentration in the 200–300 μg/mL range. The physicochemical and antibacterial performances of the hybrid particles are ascribed to the efficient silanization of SBA-15 which ensures the robustness of the PPy/Ag/NH2-SBA-15 nanocomposites on the one hand, and antibacterial effect of the continuous PPy/Ag top layer, on the other hand.