02950nas a2200145 4500008004100000245010000041210006900141260000800210490000800218520239000226100002202616700002002638700002102658856012502679 2021 eng d00aHeterogeneous nucleation in citrate synthesis of AgNPs: effect of mixing and solvation dynamics0 aHeterogeneous nucleation in citrate synthesis of AgNPs effect of cOCT0 v4213 a

The heterogeneity issues in silver nanoparticle nucleation (Lee-Meisel route) have been investigated. The final polydispersity and sphericity of the nanoparticles in the Lee-Meisel scheme are shown to depend upon the early time dynamics of silver-citrate complexation. The formation of macromolecular intermediary complexes in the early stages of the reaction is visualized based on online DLS data, TEM analysis, and the mass balances of silver and citrate ions. The reversible complexation between citrate ions and silver citrate is shown to be the limiting step that governs the directional growth of the nanoparticles. The dynamics of the complexation of citrate are seen to form a very rapid step and intense mixing was required for the complexation to happen uniformly across the reaction. This specific observation is also confirmed from the MD simulations. Thus, to get particles of high sphericity, irrespective of the reaction concentration, temperature, or reactor geometry, the mixing time should be <4 s and Da ~ 0.1. Optimal mixing conditions for isotropic growth are suggested based on the reaction kinetics and are also demonstrated with experimental evidence.

1 aDeshpande, J., B.1 aChakrabarty, S.1 aKulkarni, A., A. uhttps://library.ncl.res.in/content/heterogeneous-nucleation-citrate-synthesis-agnps-effect-mixing-and-solvation-dynamics