title: Femtosecond laser induced synthesis of Au nanoparticles mediated by chitosan.
abstract: This paper reports the synthesis of Au nanoparticles by 30-fs pulses irradiation of a sample containing HAuCl4 and chitosan, a biopolymer used as reducing agent and stabilizer. We observed that it is a multi-photon induced process, with a threshold irradiance of 3.8 × 10(11) W/cm2 at 790 nm. By transmission electron microscopy we observed nanoparticles from 8 to 50 nm with distinct shapes. Infrared spectroscopy indicated that the reduction of gold and consequent production of nanoparticles is related to the fs-pulse induced oxidation of hydroxyl to carbonyl groups in chitosan.
authors.affiliation: Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, Sao Paulo, Brazil.
authors.forename: P H D
authors.initials: PH
authors.lastname: Ferreira
authors.forename: M G
authors.initials: MG
authors.lastname: Vivas
authors.forename: L
authors.initials: L
authors.lastname: De Boni
authors.forename: D S
authors.initials: DS
authors.lastname: dos Santos
authors.forename: D T
authors.initials: DT
authors.lastname: Balogh
authors.forename: L
authors.initials: L
authors.lastname: Misoguti
authors.forename: C R
authors.initials: CR
authors.lastname: Mendonca
mesh_terms: D048271:Chitosan / Q000737:chemistry* / Q000528:radiation effects*; D006046:Gold / Q000737:chemistry* / Q000528:radiation effects*; D007834:Lasers; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D006046:Gold; D048271:Chitosan