Lignin as a multi-functional agent for the synthesis of Ag nanoparticles and its application in antibacterial coatings
Yuanyuan Li, Dongjie Yang, Pengwei Li, Zhixian Li
Abstract
Although silver nanoparticles (AgNPs) possess broad-spectrum antimicrobial activity, their intended use may adversely affect the ecosystem. In this study, alkali lignin (AL) was modified via quaternization to synthesize amphoteric lignin (AML), which was further used as a reducing and stabilizing agent for the synthesis of amphoteric [email protected] ([email protected]) composites under microwave irradiation. The [email protected] were characterized via X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy measurements. The results showed that the average particle size of AgNPs was 24.7 nm. The positively charged [email protected] had excellent antibacterial activity against Escherichia coli and Staphylococcus aureus, with a minimum inhibitory concentration of 30 ppm. The results of quartz crystal microbalance with dissipation monitoring and optical microscopy tests showed that the positively charged AML could effectively capture bacteria, which promoted the adhesion of the [email protected] to bacteria. Furthermore, the [email protected] had good compatibility with polyurethane, and when the [email protected] content in the WPU–[email protected] blend was 0.5 wt.% of the waterborne polyurethane (WPU), the prepared polyurethane film could completely inhibit bacteria growth.