Immobilization of silver nanoparticles into POEGMA polymer brushes as SERS-active substrates

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 1.9x10(6). The influence of the POEGMA's chain length on SERS performance was also investigated. Copyright (c) 2016 John Wiley & Sons, Ltd.