Stability of Ag NPs in starch solution synthesized by chemical reduction and femtosecond laser ablation

VALERIA B. ARCE; JESICA M. J. SANTILLÁN; DAVID MUÑETÓN ARBOLEDA; DIEGO MURACA; LUCÍA B. SCAFFARDI; DANIEL C. SCHINCA

Gramado

Congreso; XVI Brazilian Materials Research Society, MRS meeting, Gramado 2017, September 10 to 14; 2017

XVI Brazilian Materials Research Society

Among the different types of nanoparticles, Ag compounds have been used as antimicrobial agents since many years. Silver in the form of ions or nanoparticles (AgNP) present a broad spectrum as a bactericide, besides showing effectiveness against viruses and fungi.Silver nanoparticles in solution show remarkable physical and chemical properties that depend on size and shape. In the case of optical properties, the refractive index of the surrounding medium and the presence of a shell determine, together with the size and shape, the characteristics of the plasmon resonance.In this work we compare the stability of AgNPs made using the physical technique of laser ablation of a solid target in solution and a chemical synthesis method, using soluble starch as stabilizer in both cases.The chemical synthesis of the AgNPs was performed by adding dropwise a freshly prepared NaBH4 solution over a solution containing AgNO3 and starch. The mixture was kept under magnetic stirring in an approximately 2 hour ice / water bath.An ultrafast pulse Ti: Za laser of 100 fs duration and a central wavelength at 800 nm, focused on a solid silver target immersed in an aqueous solution of starch at different fluences, was used for ablation manufacture.Stability study of was achieved by analyzing the position of the maximum and the mean width of the extinction spectra obtained immediately after preparation and after several weeks. Z-potential measurements were also performed on the same samples with convergent results.