Facile Incorporation of Silver Nanoparticles into Quaternized Poly(2-(Dimethylamino)Ethyl Methacrylate) Brushes as Bifunctional Antibacterial Coatings

A simple strategy to fabricate bifunctional antibacterial coatings via in situ synthesis and incorporation of silver nanoparticles (AgNPs) into quaternized poly(2-(dimethylamino)ethyl methacrylate) (qPDMAEMA) brushes without using any reducing agents is reported. PDMAEMA brushes are prepared on Si wafer substrates via surface-initiated reverse atom transfer radical polymerization, which then are quaternized with ethyl bromide and hexyl bromide, respectively. The resulting qPDMAEMA-AgNP nanocomposite coatings are characterized by using Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FE-SEM), and Raman spectroscopy. FE-SEM and Raman results indicate that the AgNPs with an average diameter of 35 nm are successfully loaded into the qPDMAEMA brushes. Furthermore, the antibacterial activities of the qPDMAEMA-AgNP nanocomposite coatings against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli are investigated by both disc diffusion and colony-forming unit methods. The results show excellent antibacterial properties of the nanocomposite coatings. The influence of the length of the quaternization agents on their antibacterial properties is also investigated.