Abstract View
Langevin Dynamics Simulation of Porous Particulate Film Deposition with Polydisperse and Agglomerated Particles
JIHYEON LEE, Christopher J. Hogan, University of Minnesota
Abstract Number: 9
Working Group: Nanoparticles and Materials Synthesis
Abstract
Aerosol synthesis methods are often coupled with deposition in an effort to manufacture particulate coatings. The structural properties of such coatings are largely dependent on the size and morphology of depositing particles, along with the physics governing particle transport to the deposition substrate. This study investigated the effects of the polydispersity and morphology of depositing particles on resulting particulate films on a flat substrate via Langevin dynamics simulation. In simulations, individual particle trajectories were monitored as a constant force drove particles to the substrate, accounting both for particle inertia and thermal (Brownian) motion. Particles were assumed to bind upon contract with the substrate or with previously deposited particles. Deposited films were characterized via analysis of their pore size distributions and porosities. To demonstrate how such structural parameters can effect film physical properties, a thermal conductivity model accounting for non-continuum conduction within pores was constructed and used to predict deposit thermal conductivities. In deposition simulations, we considered partial coalescence, polydispersity, and extent of aggregation for depositing particles. Polydisperse particles were sampled from a log-normal distribution with assigned geometric standard deviations, while aggregates were composed of a prescribed number of primary particles. The deposition of polydisperse and aggregated particles broadened the pore size distribution and increased the mode pore size. Thermal conductivity predictions suggest that particulate films can achieve thermal conductivities comparable to that of conventional aerogels.