title: Brownian dynamics simulation of monolayer formation by deposition of colloidal particles: a kinetic study at high bulk particle concentration.
abstract: Brownian dynamics simulations (BDS) of sedimentation and irreversible adsorption of colloidal particles on a planar surface were carried out at bulk particle volume fractions (φ) in the range 0.05 to 0.25. The sedimentation and adsorption of colloidal particles were simulated as a non-sequential process that allows simultaneous settling and adsorption of particles. A kinetic model for the formation of particle monolayers based on the available surface fraction (θ(A)) is proposed to predict simulation results. The simulations show a value of 0.625 for the maximum fractional surface coverage (θ(∞)) and a monolayer structure insensitive to φ. However, the kinetic order of the monolayer formation process has a strong dependence with φ, changing from a value close to a unit, at low φ, to a value around two at high φ. This change in the kinetic reaction order is associated to differences of particle adsorption mechanism on the surface. At low φ values, the monolayer formation is achieved by independent adsorption of single particles and the reaction order is close to 1. At high φ values, the simultaneous adsorption of two particles on the surface leads to an increase of the reaction order to values close to 2.
authors.affiliation: Colloids Group, Institute of Chemistry, University of Antioquia, Medellin, Colombia.
authors.forename: C A
authors.initials: CA
authors.lastname: Pérez
authors.forename: A
authors.initials: A
authors.lastname: Moncho-Jordá
authors.forename: R
authors.initials: R
authors.lastname: Hidalgo-Álvarez
authors.forename: H
authors.initials: H
authors.lastname: Casanova
mesh_terms: D000327:Adsorption; D000465:Algorithms; D003102:Colloids / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D009038:Motion; D013499:Surface Properties
chemical_list: D003102:Colloids