Fractal property of silica aggregate

Silica aggregates were prepared by base-catalyzed hydrolysis and condensation of alkoxides in alcohol. PEG was used as organic modifier. The sols were characterized using Small Angle X-ray Scattering (SAXS) with synchrotron radiation as X-ray source. The structure evolution during the sol-gel process was determined and described using the concept of fractal geometry. SAXS results show that the silica aggregates are mass fractals, fractal dimensions span the regime 0.30-2.56 corresponding to more branched and compact structures. Both RLCA and Eden models dominate the kinetic growth under base-catalyzed condition