Controlled thermal shrinking of gold nanoparticle-decorated polystyrene substrate for advanced surface-enhanced Raman spectroscopy

Surface-enhanced Raman spectroscopy (SERS) is a promising technique for future high-sensitivity chemical sensors. The main deficiencies that restrict the large-scale application of SERS lie in its high cost, low reproducibility, and poor signal uniformity. In this letter, we report the primary exploration of a facile dip coating - thermal shrinking method to produce gold (Au) nanoparticle decorated flexible polymer substrate for SERS. Briefly, Au nanoparticles dispersed in DI-water were anchored on to a polystyrene film via controlled dip coating, which was followed by a thermal treatment process to shrink the polymer film. We observe a polymer volume shrinking rate of 20% after heating, which results in a particle density increase of more than 10 times. Significant enhancement of Raman signals was observed for the R6G molecules anchored on the shrunk substrate, demonstrating our methodology is feasible, reliable, and promising for future large-scale application of SERS-based chemical sensors.