One-pot green synthesis and antimicrobial activity of exfoliated Ag NP-loaded quaternized chitosan/clay nanocomposites

A rapid and green method is reported to synthesize silver nanoparticles (Ag NPs) and simultaneously achieve exfoliated chitosan/clay nanocomposite under microwave irradiation, in which quaternized chitosan (QCS), montmorillonite (MMT) and Gemini surfactant were used as reducing and stabilizing agents, other chemical reductants were not involved. XRD, FT-IR, NMR, TEM and AAS were performed to characterize Ag NP-loaded QCS/clay nanocomposites. The results indicated that the formation of spherical Ag NPs (about 26 nm) were mainly associated with reduction effect of QCS, surfactant and clay hardly participate in the synthesis of Ag NP, but benefited its formation. During the formation of Ag NPs, the layers of clay were peeled, the exfoliated Ag NP-loaded QCS/clay nanocomposites were obtained. Moreover, Ag NP-loaded QCS/clay nanocomposites showed excellent antimicrobial activity. The lowest minimum inhibition concentration against microorganisms was 0.00001 wt%. At last, the antimicrobial mechanism was evaluated by TEM and SEM micrographs.