Application of the Density Variation Methodon Calciumcarbonate Nanoparticles

Abstract

The simultaneous determination of particle size and density distributions by the so called density variation method via measurement of the same sample in H₂O and D₂O proved to be of great value for latex systems. However, many colloids of practical interest are inorganic or inorganic-organic hybrid colloids. Their density is usually much higher than that of the solvents so that the density variation method appears of limited applicability. In addition, these systems are usually charged – a complication, which was so far not yet considered in the theory for the density variation method. In this work, we apply this method to the determination of the particle size and density of CaCO₃ precursor particles, which form superstructures in order to elucidate their crystal modification. Interestingly, the particle densities can be determined rather reasonably, whereas the particle size is much more influenced by the nonideality.