Restricted Diffusion in Silica Sol-Gel Nanoparticles

✍ Scribed by S. Veith; E. Hughes; M. Perren; S. E. Pratsinis

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: German
• Weight: 53 KB
• Volume: 75
• Category: Article
• ISSN: 0009-286X
• DOI: 10.1002/cite.200390384

✦ Synopsis

In this work, ultra small-angle x-ray scattering (USAXS) of agglomerate and non-agglomerate flame-made silica nanoparticles is investigated systematically for ubiquitous characterization of particle size and degree of agglomeration. Primary particle diameters determined from the USAXS particle volume to surface ratio were compared to those obtained from nitrogen adsorption (BET) measurements. Independent of the silica precursor state (vapor or liquid), production rate (5 to 1100 g/h), degree of agglomeration or flame conditions (premixed, diffusion or spray flame), there is good agreement between BET and USAXS for the average primary particle diameter as shown in the figure for various agglomerated fumed silica powders [2]. Furthermore, the USAXS data reveal the dynamics and interrelation between primary particle diameter and the agglomerate radius of gyration as a function of the fuel and precursor flow rate for various vapor-and liquid-fed flame reactors.