Hybrid silver nanoparticles with controlled morphology as efficient substrates for surface-enhanced Raman scattering

This work reports on the efficient performance of hybrids particles with silver nanoparticles (AgNPs) distributed within single polymer molecules with star-like topology as Surface Enhanced Raman Scattering (SERS) supports. First, the library of the star-like polymers with poly (acrylic acid)-block-polystyrene (PAA-b-PS) arms was obtained via atom transfer radical polymerization (ATRP) using a "core-first" approach. Then, hybrid silver nanoparticles were synthesized in a controlled way within the prepared single molecules playing the role of molecular templates for AgNPs. Finally, the hybrid particles were tested as novel substrates for SERS using crystal violet as an analyte. Synthesized star-like templates had varied number of arms within the single star, the order of PAA and PS blocks, their degree of polymerization, and the molar ratio of the carboxylic groups of PAA block to the nanoparticles' precursor. Additionally, the minimum analyte concentration required for SERS was determined. The number of arms within a polymer template plays a crucial role in the synthesis of silver nanoparticles and observed SERS effect. Prepared substrates were stable for long time and allowed the detection of the analytes on the nanomolar level.