Composite blends of gold nanorods and poly(t-butylacrylate) beads as new substrates for SERS.

Polymer based composites containing metal nanoparticles are shown to provide new substrates for SERS detection and simultaneously enable the development of new tools for molecular sensing. A very important aspect on the use of hybrid materials relates to the observation of synergistic effects that result from the use of distinct components such as a polymer and metal nanoparticles. We report here the preparation of new SERS substrates made from blends of colloidal Au (nanospheres and nanorods) and PtBA (poly(t-butylacrylate)). The observed SERS enhancement depends on the characteristics of the obtained hybrid material. When compared to the starting Au colloids, the Au/PtBA nanocomposites led to SERS spectra with more intense bands, using 2,2'-dithiodipyridine as molecular probe. The origin of the stronger Raman signal in this case, is possibly due to a combination of events related to the nanocomposite characteristics, including the formation of Au assemblies at the polymer surface due to particle clustering, and the absorption increase in a spectral region closer to the laser excitation wavelength. The strategy described here is a low-cost process with potential for the up-scale fabrication of SERS substrates, namely by using other types of nanocomposites.