title: Silica nanoparticles grown and stabilized in organic nonalcoholic media.
abstract: This work features an alternative approach to the well-documented preparation of silica nanoparticles in protic media. We present here the one-pot synthesis of silica nanoparticles of adjustable size (between 18 and 174 nm), prepared and stabilized in organic nonalcoholic solvents. This novel route is based on hydrolysis and condensation of tetraethoxysilane, using water as reactant and different primary amines (butylamine, octylamine, dodecylamine, hexadecylamine) as catalysts in tetrahydrofuran or dimethoxyethane. The growth rate can be finely adjusted, and the first stages of the formation are observed by transmission electronic microscopy, revealing a silicated network in which the silica particles are formed and then released in solution. The amine plays not only a catalyst role but is also implied, as well as the solvent, in the stabilization process and the size control of the particles. A detailed NMR study demonstrates a core-shell structure in which the silica core is surrounded by a layer of alkylammonium ions together with solvent.
authors.affiliation: Université de Toulouse, INSA, UPS, CNRS, LPCNO (Laboratoire de Physique et Chimie des Nano-Objets), 135 avenue de Rangueil, F-31077 Toulouse, France.
authors.forename: Nancy
authors.initials: N
authors.lastname: El Hawi
authors.forename: Céline
authors.initials: C
authors.lastname: Nayral
authors.forename: Fabien
authors.initials: F
authors.lastname: Delpech
authors.forename: Yannick
authors.initials: Y
authors.lastname: Coppel
authors.forename: Alfonso
authors.initials: A
authors.lastname: Cornejo
authors.forename: Annie
authors.initials: A
authors.lastname: Castel
authors.forename: Bruno
authors.initials: B
authors.lastname: Chaudret
mesh_terms: D000438:Alcohols / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry*; D010316:Particle Size; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D000438:Alcohols; D009930:Organic Chemicals; D000644:Quaternary Ammonium Compounds; D012822:Silicon Dioxide; C009405:tetrabutylammonium