Gelation of Colloidal Silica

Abstract

Classical light-scattering studies of colloidal silica gels show that they have a fractal structure for length scales shorter than a concentration-dependent crossover length $\ensuremath{\xi}$, and behave like a collection of nearly randomly distributed scattering centers for length scales greater than $\ensuremath{\xi}$. Our data show that $\ensuremath{\xi}$ has a power-law concentration dependence, $\ensuremath{\xi}\ensuremath{\propto}{c}^{\ensuremath{-}1.17\ifmmode\pm\else\textpm\fi{}0.1}$.