title: Control of silver-polymer aggregation mechanism by primary particle spatial correlations in dynamic fractal-like geometry.
abstract: Silver nanocrystals have been prepared by reacting silver nitrate with ascorbic acid in aqueous solution containing a low concentration of a commercial polynaphthalene sulfonate polymer (Daxad 19). Various crystalline morphologies have been obtained simply by tuning the reaction temperature. We have investigated the nanoparticle formation mechanism at three different temperatures by in situ and time resolved small angle X-ray scattering measurements. By modeling the scattering intensity with interacting spherical particles in a fractal-like polymer-Ag matrix, we found signatures of nucleation, growth and assembly of primary particles of about 15-20 nm. We observed how the time evolution of both spatial correlations between primary particles and the dynamic fractal geometry of the polymer-Ag matrix could influence and determine both the aggregation mechanism and the morphology of forming nanostructures in solution.
authors.affiliation: CNR- Istituto di Cristallografia, Via Salaria, Km 29.300, Monterotondo Stazione, RM I-00015, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Campi
authors.forename: Alessandra
authors.initials: A
authors.lastname: Mari
authors.forename: Augusto
authors.initials: A
authors.lastname: Pifferi
authors.forename: Heinz
authors.initials: H
authors.lastname: Amenitsch
authors.forename: Michela
authors.initials: M
authors.lastname: Fratini
authors.forename: Lorenza
authors.initials: L
authors.lastname: Suber
mesh_terms: D001205:Ascorbic Acid / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009282:Naphthalenesulfonates / Q000737:chemistry; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D009282:Naphthalenesulfonates; D011108:Polymers; C445092:poly(naphthalenesulfonic acid); D014867:Water; D012834:Silver; D001205:Ascorbic Acid