title: Fluorescence correlation spectroscopy directly monitors coalescence during nanoparticle preparation.
abstract: Dual color fluorescence cross-correlation spectroscopy (DC FCCS) experiments were conducted to study the coalescence and aggregation during the formation of nanoparticles. To assess the generality of the method, three completely different processes were selected to prepare the nanoparticles. Polymeric nanoparticles were formed either by solvent evaporation from emulsion nanodroplets of polymer solutions or by miniemulsion polymerization. Inorganic nanocapsules were formed by polycondensation of alkoxysilanes at the interface of nanodroplets. In all cases, DC FCCS provided fast and unambiguous information about the occurrence of coalescence and thus a deeper insight into the mechanism of nanoparticle formation. In particular, it was found that coalescence played a minor role for the emulsion-solvent evaporation process and the miniemulsion polymerization, whereas substantial coalescence was detected during the formation of the inorganic nanocapsules. These findings demonstrate that DC FCCS is a powerful tool for monitoring nanoparticles genesis.
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Schaeffel
authors.forename: Roland Hinrich
authors.initials: RH
authors.lastname: Staff
authors.forename: Hans-Juergen
authors.initials: HJ
authors.lastname: Butt
authors.forename: Katharina
authors.initials: K
authors.lastname: Landfester
authors.forename: Daniel
authors.initials: D
authors.lastname: Crespy
authors.forename: Kaloian
authors.initials: K
authors.lastname: Koynov
mesh_terms: D003102:Colloids / Q000737:chemistry; D004655:Emulsions / Q000737:chemistry; D057446:Hydrodynamics; D008027:Light; D053769:Nanocapsules / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods; D011108:Polymers / Q000737:chemistry; D011137:Polystyrenes / Q000737:chemistry; D012542:Scattering, Radiation; D012821:Silanes / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013997:Time Factors
chemical_list: D003102:Colloids; D004655:Emulsions; D053769:Nanocapsules; D011108:Polymers; D011137:Polystyrenes; D012821:Silanes; D012997:Solvents