Evidence of structural reorganization during aggregation of silica nanoparticles

Abstract

International audienceSilica nanoparticles have been produced by neutralization of sodium silicate. The obtained suspension was unstable because of the high value of the ionic strength of the medium. Aggregation of the particles has been monitored thanks to a combination of <i>in situ</i> turbidity and dynamic light scattering (DLS) measurements. An optical model has been developed to extract both fractal dimension D_f and primary particle radius r_pp of the formed aggregates from these data. The obtained results clearly indicate a densification of the clusters as aggregation proceeds. A correlation between our experimental turbidity values and hydrodynamic radii was found. Comparison with calculated dimensionless numbers showed that a constant D_f could not explain the observed trend. A fractal dimension dependent on the number of particles inside the aggregate N_pp is thus suggested

Dynamics of oligomerization of silicate solution studied by Molecular Dynamics

“…The control of the precipitation of silica from basic solutions is a challenging task for manufacturers. Nowadays, we dispose of a vast amount of data concerning the growth of silica particles, their aggregation, and agglomeration, as well as the dependence of those steps on experimental conditions [1], [2]. However, we have not yet reached a full understanding of the process.…”

dynamics of non-dense sodium silicate - water system studied by molecular dynamics

“…Precipitated silica, with its application in many branches of the industry -rubber, agrochemical, ceramics, oral care, food and feed, among others, has gained popularity in recent years. Thus, nowadays, we dispose of a vast amount of data concerning the growth of silica particles, their aggregation, and agglomeration, as well as the dependence of those steps on experimental conditions [1], [2]. However, we have not yet reached a full understanding of the process.…”