An Example of X-ray Nanochemistry: SERS Investigation of Polymerization Enhanced by Nanostructures under X-ray Irradiation

We demonstrated for the first time enhanced formation of polymers on nanostructures under X-ray irradiation. Surface enhanced Raman spectroscopy (SERS) using silver core-gold shell nanocoreshells (Ag@Au NCSs) as the SERS substrate was employed to quantify the amount of polymers on the surface. The yield of surface-grown polyaniline (PAN!) from X-ray-irradiated aniline monomers in aqueous solution of the NCSs was 28 times that of aniline-mixed NCSs without X-rays or 400 times that with the monomers alone irradiated with X-rays. The enhancement was dose rate-dependent and is believed to originate from Ag/Au ionic species created from X-ray generated hydroxyl radicals (center dot OH) reacting with NCSs. The resulting Ag/Au ionic species on NCSs then initiate PANI formation from aniline molecules absorbed on the NCS surface. The results presented here help advance a new field of X-ray nanochemistry and may inspire applications requiring X-ray-triggered formation of polymers on nanomaterials.