In the real reaction

In the real reaction, two processes may occur simultaneously. At first, Ag nanoparticles are formed through homogenous nucleation and grow into the direction of the lowest energy {111} plane. The first step was the generation of Ag nanoparticles by the homogenous nucleation from the added silver seeds which served as nuclei for silver atoms formed during the irradiation reduction of AgNO3. It was found that the formation of the rod-like PVA micelles was strongly depended on the mole ratio of PVA to AgNO3. PVA has polyvinyl skeleton with polar groups containing oxygen atoms and can form complex with Ag through coordination covalent bond. Second stage involves merging and fusing of the reduced particles to form nanorods in the template by photo-thermal effect of gamma irradiation.
The function of PVA is to form coordination complex with Ag ions and to adsorb selectively on facets of Ag nanoparticles. Due to the presence of –C=O group in PVA, binding capacity to the surface of Ag particle increases. The interaction between Ag crystals and –C=O group of PVA decreases the growth of crystal {100} plane comparatively with {111} plane. Due to high difference in energy of side surfaces {100} facets and end surfaces {111} facets, there is a great difference of reactivity between {100} facets and {111} facets of Ag rods. Consequently, side surface was completely blocked with PVA and the ends surface was partially blocked with PVA. These investigations show that the PVA macromolecules interact more strongly with{100} facets of Ag than {111} facet of Ag. There is a strong preferred orientation along the {111} plane of the Ag crystals as shown in figure (6).