Radiation Induced Generation of Core-Shell Nanoparticles in Polyelectrolyte Films of Poly(acrylic acid)-Poly(ethylenimine) Complex with Copper and Silver Ions

Tuning the size and structure of bimetallic nanostructures is for the design of functional compounds with desirable properties. In this paper, the mechanisms that control radiation-induced assembly of bimetallic core-shell nanoparticles in polyelectrolyte matrices are discussed. The stages of Ag/Cu nanoparticle formation in the films of poly(acrylic acid)-poly(ethylenimine) complexes have been studied for the first time using X-ray diffraction analysis including synchrotron techniques combined with electron microscopy. The generation of silver nanostructures proceeds via their parallel nucleation and growth during the entire process of bimetallic nanoparticles formation. The sizes of shells are controlled by the competition between the growth of silver nanostructures and the formation of shells. Copper shells are generated in two stages: (1) ultrasmall nanostructures, which are slowly formed at the first stage, prevent the growth of silver nuclei; (2) as the shell improves, the growth rate of copper nanostructures increases dramatically. The results obtained demonstrate the possibility of single-stage controllable radiation-initiated synthesis of core-shell bimetallic nanoparticles directly in interpolyelectrolyte films.