Starch-directed green synthesis, characterization and morphology of silver nanoparticles

Silver nanoparticles were prepared by a simple chemical reduction method using ascorbic acid and starch as reducing and stabilizing agents, respectively. The effect of starch, silver ions and ascorbic acid was studied on the morphology of the silver nano-particles using UV–visible spectrophotometry. The initial reaction time min and amount of starch were important parameters for the growth of Ag-nanoparticles. The morphology was evaluated from transmission electron microscopy (TEM). The truncated triangle nano-plates (from 17 to 30 nm), polyhedron, spherical with some irregular shaped Ag-nanoparticles were formed in presence of starch. Particles are aggregated in an irregular manner, leads to the formation of butterfly-like structures of silver. Starch acts as a stabilizing, shape-directing and capping agent during the growth processes. Silver nanoparticles adsorbed electrostatically on the outer OH groups of amylose left-handed helical conformation in solution.

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► Soluble starch-directed silver nanoparticles were prepared using ascorbic acid as reducing agent.
► Morphology strongly depends on the amylose concentrations.
► Silver nanoparticles adsorbed on the hydroxy groups of soluble starch through electroistatic interactions, leads to the formation of butter fly-like silver.