Preparation of hollow silver-polymer microspheres with a hierarchical structure for SERS

The Surface-enhanced Raman scattering (SERS) effect on the surface of metal conductors can significantly improve the sensitivity of molecular detection. Therefore, it is widely used in the field of chemical sensors. The nanostructure of the metal surface strongly influences the strength of the SERS by adsorption and surface electric field. Herein, we combine microfluidic technology with electroless silver plating to produce hollow microspheres with different wall thicknesses. The microspheres have a diameter of 400 μm and a spherical shell thickness of 40–100 μm. The spherical shell has a porous structure formed by phase separation, on which nanosilver particles can be deposited. The silver-polymer hybrid microspheres can adsorb dyes in aqueous solution and produce significant SERS effects, and the Raman signal enhancement factors can be up to 7.11 × 10 11 . Computational simulations and experimental results show that the Raman enhancement effect is related to the distance between the silver particles on the surface and the hollow structure of the microspheres.