Determination of Interparticle Forces by Colloidal Particle Scattering: A Simulation Study

Colloidal particle scattering is a recently developed method for the determination of forces between micron-sized particles, which has given promising results. Inversion of the experimental scattering results to retrieve the interaction force requires the development of reliable computer code to match theory and experiment. We review the method used, discuss some operational details, and present some validating results for shear and sedimentation fields that compare favorably with the literature. We have used the simulation to compare particle scattering in a simple shear field for a range of exponential surface forces and discuss the sensitivity of these results to changes in potential parameters. We also discuss the sensitivity in relation to sources of error and their magnitude. In particular, we have incorporated a Brownian dynamics algorithm and compared the level of thermal noise with a simple theoretical formula. We introduce a straightforward means of representing the data and find that order of magnitude changes in the parameters evoke changes in the scattering pattern roughly equivalent to the Brownian noise level for a typical experiment with Pe=120. The results demonstrate the ability of the method, in principle, to distinguish between interaction potentials of different ranges and energy parameters. Copyright 2000 Academic Press.