Measurements of the interactions between colloidal particles and between particles and interfaces are crucial to understanding the stability, structure, and dynamics of colloidal dispersions.  It is difficult to directly measure these interactions for two main reasons: (1) they are typically short-ranged, operating over distances a fraction of the particle diameter; and (2) the measurement technique can often perturb the interaction. I will discuss how holographic microscopy can be used to measure colloidal interactions non-invasively and with high precision.  An important part of the measurement is inferring the interaction from the experimentally recorded holograms.  To do this, we use a Bayesian approach to fit a scattering model to the data. I will show how this approach allows us to infer separations to nanometer-scale precision. The Bayesian approach also allows us to account for correlations between the uncertainties in the other fitting parameters and marginalize these to obtain accurate uncertainties on the parameters determining the interaction potential. I will discuss how we use this approach to measure particle-particle potentials and interactions between a particle and a liquid interface.

High-precision measurements of colloidal interactions using holographic microscopy and Bayesian inference

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.