The Sedimentation of Colloidal Nanoparticles in Solution and Its Study Using Quantitative Digital Photography

J. Midelet, A. H. El-Sagheer, T. Brown, A. G. Kanaras and M. H. V. Werts. Part. Part. Syst. Char. 2017.


Sedimentation and diffusion are important aspects of the behavior of colloidal nanoparticles in solution, and merit attention during the synthesis, characterization, and application of nanoparticles. Here, the sedimentation of nanoparticles is studied quantitatively using digital photography and a simple model based on the Mason–Weaver equation. Good agreement between experimental time-lapse photography and numerical solutions of the model is found for a series of gold nanoparticles. The new method is extended to study for the first time the gravitational sedimentation of DNA-linked gold nanoparticle dimers as a model system of a higher complexity structure. Additionally, simple formulas are derived for estimating suitable parameters for the preparative centrifugation of nanoparticle solutions.