Preparation of silver nanoparticles on free-standing polyaniline/cellulose acetate blend film for surface-enhanced Raman scattering application

Polyaniline (PANI) has been used as a precursor for the preparation of surface-enhanced Raman scattering (SERS) substrates because of its ability to act as a reducing agent and binding site of plasmonic metal nanoparticles (NPs). However, the processability of PANI is limited due to its poor mechanical properties. In this work, a simple preparation of a free-standing polymeric blend film by mixing hydrochloric acid–doped polyaniline nanofibers (PANI) and cellulose acetate (CA) is demonstrated. This PANI/CA was used as a reducing agent for synthesizing Ag nanoparticles (AgNPs). The formation of globular NPs and cubic microstructures on the surface of the film was observed, as well as the formation of AgCl due to the presence of chloride ions in the PANI structure. The film was then treated with hydrazine to reduce AgCl to AgNPs resulting in isolated and clustered AgNPs. Rhodamine 6G dye was used as a probe molecule for SERS measurements. This new composite film PANI/CA@Ag treated with hydrazine was successfully applied as a SERS substrate. This substrate enhancement of Rhodamine 6G dye Raman bands was estimated, and the Rhodamine 6G dye could be detected even at a concentration of 10 −7 mol L −1 . Graphical Abstract