Vesicle-like polymer/silver composite microspheres with excellent toughness for surface-enhanced Raman scattering
Hollow noble metal microspheres are constrained by intrinsic brittleness, which limits their practical deployment in catalysis, electronics, and chemical detection. This study reports a scalable fabrication route to vesicle-like polystyrene-silver (SPS@Ag) composite microspheres with enhanced toughness. Uniform polystyrene (PS) microspheres of approximately 1.5 μm diameter were synthesized via dispersion polymerization, sulfonated to introduce surface sulfonate groups, and sensitized with Sn2+ ions to facilitate electrostatic adsorption. Subsequent in situ chemical reduction of [Ag(NH3)2]+ yielded well-defined core-shell SPS/Ag composite microspheres with tunable shell thickness controlled by the number of reduction cycles. Removal of the PS core using DMF produced hollow vesicle-like SPS@Ag microspheres. The incorporation of SPS within the silver membrane confers exceptional toughness, mitigating the collapse typically observed during template removal. Surface-enhanced Raman scattering (SERS) performance was evaluated using rhodamine 6G (R6G) as a probe molecule. The vesicle-like SPS@Ag microspheres exhibited a significant increase in Raman enhancement factor compared to their core-shell counterparts, demonstrating their potential as highly efficient SERS substrates for analytical chemistry, sensing technologies, and catalytic processes.