(93c) Fabrication of Large Area Surface-Enhanced Raman Spectroscopy Substrate with Rough Surface PMMA Colloidal Particle

Surface enhanced Raman spectroscopy (SERS) has drawn significant attention over the past decades as a unique technique that can achieve detection at the single molecular level. However, cost-effective strategies for fabrication of the SERS substrates with large area uniformity and consistent signal enhancement are still illusive. Here we report an efficient fabrication route of SERS substrates via convective flow coating from micro-colloids, followed by thin film deposition of metals such as gold and silver. To enhance the surface plasmon resonance, we synthesize PMMA microspheres with rough surfaces, which increase the density of hot spots significantly compared with particles with smooth surface. The corrugated particles are synthesized with delayed addition of the crosslink agent (e.g., DVB) during dispersion polymerization. Key parameters that affect the surface roughness such as the reaction temperature, molecular weight of surfactant, the start time of delayed addition are studied systematically. The surface plasmon resonance of these substrates strongly depend on the degree of roughness on the support colloidal array, metal film thickness, and the type of meal thin film. The enhancement factor and uniformity of these SERS substrates for detecting crystal violet, are also been investigated.