Formation of Silver Nanoparticles at the Air−Water Interface Mediated by a Monolayer of Functionalized Hyperbranched Molecules

• Published in: Langmuir Vol. 22; no. 3; pp. 1027 - 1037
• Main Authors: Rybak, Beth M, Ornatska, Maryna, Bergman, Kathryn N, Genson, Kirsten L, Tsukruk, Vladimir V
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 31.01.2006
• Subjects: Catalysis; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Micelles. Thin films; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Water; Gas liquid interface; Monolayer; Catalytic reaction; Amino group; Nanoparticle; Micelle; Ions; Dimension; Air water interface; Template; Amine; Alkyl; Potassium addition; Silver ion; Oxidation; Catalysis; Surface area; Structure; Formation mechanism; Diameter; Hydroxyl
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la0525269

Nanofibrillar micellar structures formed by the amphiphilic hyperbranched molecules within a Langmuir monolayer were utilized as matter for silver nanoparticle formation from the ion-containing water subphase. We observed that silver nanoparticles were formed within the multifunctional amphiphilic hyperbranched molecules. The diameter of nanoparticles varied from 2−4 nm and was controlled by the core dimensions and the interfibrillar free surface area. Furthermore, upon addition of potassium nitrate to the subphase, the Langmuir monolayer templated the nanoparticles' formation along the nanofibrillar structures. The suggested mechanism of nanoparticle formation involves the oxidation of primary amino groups by silver catalysis facilitated by “caging” of silver ions within surface areas dominated by multibranched cores. This system provides an example of a one-step process in which hyperbranched molecules with outer alkyl tails and compressed amine-hydroxyl cores mediated the formation of stable nanoparticles placed along/among/beneath the nanofibrillar micelles.