Two-dimensional synthesis of silver nanoparticle in situ Langmuir films from the reduction of silver sulfadiazine

Author(s)

Assis, D. R. ; Ueyama, V. N. ; Santos, C. C. ; Davolos, M. R. ; Jafelicci Jr, M.

• Document type: Journal article
• Source: Thin Solid Films; v. 746, p. 9-pg., 2022-02-11.

Abstract

Two-dimensional (2D) arrangement of monodisperse metallic nanoparticles (NPs) has attracted attention because of the unique properties of this assembly. These properties offer new perspectives for several applica-tions. Thin film preparation techniques involve the synthesis of NPs through chemical methods and their sub-sequent attachment to various substrates based on different interactions. Langmuir-Blodgett (LB) technique is a promising method, which offers possibilities of in-situ preparation of metallic NP-structured and ordered monolayer films. In this study, 2D AgNPs were synthesized in situ through the reduction of a Langmuir monolayer consisting of a mixture of silver sulfadiazine (AgSD) molecules and stearic acid (SA) surfactant at the air-water interface. Two different Ag reduction methods were used. First, a NaBH4 aqueous solution was used as the subphase to react with the mixed Langmuir monolayer films. Second, the mixed films were irradiated by an ultraviolet (UV) light source (lambda = 254 nm) for different time intervals. Scanning electron microscope images, energy-dispersive X-ray spectra, and contact angle measurements show that AgSD was an efficient precursor for the synthesis of Ag NPs LB films with long-range order. A small amount of SA is sufficient to cause the arrangement of the NPs, prevent their aggregation, and provide a hydrophobic characteristic to the Ag NPs LB films. Furthermore, the chemical reduction method using NaBH4 is better than the reduction under UV light for the synthesis of Ag NPs arrangement. (AU)