(388u) Dissipative Particle Dynamics Simulation of Sonication-Mediated Particle Interactions

Sonication
is a powerful dispersion technique that has been used successfully to disperse
agglomerates and break partially formed bridges of nano-scaled particles. For
micro-scaled particles, recent work in our lab suggests that it may also serve
as a viable ?thermalization? technique in order to promote close-packed, highly
ordered colloidal crystal formation of large (non-Brownian) particles on a
surface. In this study, we computationally explore the impact of sonication on particle
cluster formation using the Dissipative Particle Dynamics (DPD) technique. DPD
is a particle-based (i.e. Lagrangian) simulation technique that captures
meso-scopic dynamics of multiphase flows by coarse-graining intermolecular
forces. At its most basic, this coarse-graining results in a conservative,
dissipative, and random force. Here, the effect of sonication is incorporated
into the DPD method as an oscillatory external force with high frequency and
low amplitude. By adding the external force from the sonication, we can inspect
the microscopic details of the relative importance of the particle interactions
as a function of driving parameters (frequency and amplitude) and compare our
results to experimental measurements.