Correlation of Secondary Particle Number with the Debye-Hückel Parameter for Thickening Mesoporous Silica Shells Formed on Spherical Cores.

Mesoporous silica shells were formed on nonporous spherical silica cores during the sol-gel reaction to elucidate the mechanism for the generation of secondary particles that disturb the efficient growth of mesoporous shells on the cores. Sodium bromide (NaBr) was used as a typical electrolyte for the sol-gel reaction to increase the ionic strength of the reactant solution, which effectively suppressed the generation of secondary particles during the reaction wherein a uniform mesoporous shell was formed on the spherical core. The number of secondary particles ( ) generated at an ethanol/water weight ratio of 0.