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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.

Surface‐enhanced Raman scattering (SERS) has attracted a great deal of interest during the past four decades and emerged as an ultrasensitive optical technique for chemical and biomedical analysis. It is widely accepted that the facile fabrication of SERS substrates with high activity and good reproducibility is of crucial importance for their applications. Herein, we report on a fast and robust method for the synthesis and immobilization of silver nanoparticles (AgNPs) into poly(oligo(ethylene glycol) methacrylate) (POEGMA) brushes under mild conditions without using any reducing agents. POEGMA brushes of different chain lengths were synthesized directly on silicon wafers by surface‐initiated atom transfer radical polymerization with various reaction time. X‐ray photoelectron spectroscopy and field emission scanning electron microscope measurements indicated that the AgNPs were firmly and homogeneously embedded into POEGMA brushes. The resulting POEGMA–AgNP hybrid films were employed as SERS substrates for the detection of 4‐aminothiophenol, giving rise to an enhancement factor of up to 1.9 × 106. The influence of the POEGMA's chain length on SERS performance was also investigated. Copyright © 2016 John Wiley & Sons, Ltd.

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