Impact of PS/SiO2 morphologies on the SERS activity of PS/SiO2/Ag nanocomposite particles

To understand the relationship between the morphology of carboxyl-functionalized polystyrene/silica (PS/SiO 2 ) nanocomposite microspheres and the surface-enhanced Raman scattering (SERS) performance of PS/SiO 2 /Ag nanocomposite particles, core-shell and raspberry-like PS/SiO 2 composite microspheres were used as templates to prepare PS/SiO 2 /Ag nanocomposite particles. The core-shell and raspberry-like structured PS/SiO 2 templates were prepared via in situ sol-gel reaction by hydrolysis tetraethyl orthosilicate (TEOS) in alkali solution. Silver nanoparticles (10–50 nm) were loaded on the PS/SiO 2 templates’ surface by chemical reduction. The morphology and structure of the PS/SiO 2 /Ag particles were characterized by TEM, SEM, X-ray diffraction (XRD), and ultraviolet-visible (UV-vis) spectroscopy. Rhodamine 6G (R6G) was selected as a model chemical to study the enhancement performance of substrate constructed by PS/SiO 2 /Ag nanocomposite. Results indicated that the PS/SiO 2 /Ag nanocomposite prepared based on the core-shell templates showed higher SERS activity. The beneficial effect was associated with a lower specific area of core-shell structure and the larger average diameter of nanosilvers than that of the raspberry-like templates.