title: Non-linear, non-monotonic effect of nano-scale roughness on particle deposition in absence of an energy barrier: Experiments and modeling.
abstract: Deposition of colloidal- and nano-scale particles on surfaces is critical to numerous natural and engineered environmental, health, and industrial applications ranging from drinking water treatment to semi-conductor manufacturing. Nano-scale surface roughness-induced hydrodynamic impacts on particle deposition were evaluated in the absence of an energy barrier to deposition in a parallel plate system. A non-linear, non-monotonic relationship between deposition surface roughness and particle deposition flux was observed and a critical roughness size associated with minimum deposition flux or "sag effect" was identified. This effect was more significant for nanoparticles (<1 μm) than for colloids and was numerically simulated using a Convective-Diffusion model and experimentally validated. Inclusion of flow field and hydrodynamic retardation effects explained particle deposition profiles better than when only the Derjaguin-Landau-Verwey-Overbeek (DLVO) force was considered. This work provides 1) a first comprehensive framework for describing the hydrodynamic impacts of nano-scale surface roughness on particle deposition by unifying hydrodynamic forces (using the most current approaches for describing flow field profiles and hydrodynamic retardation effects) with appropriately modified expressions for DLVO interaction energies, and gravity forces in one model and 2) a foundation for further describing the impacts of more complicated scales of deposition surface roughness on particle deposition.
authors.affiliation: Department of Civil and Environmental Engineering, University of Waterloo, 200 University Ave W., Waterloo, ON, N2L 3G1, Canada.
authors.forename: Chao
authors.initials: C
authors.lastname: Jin
authors.affiliation: Xagenic Inc., 55 York Street, Suite 1000, Toronto, Ontario, M5J 1R7, Canada.|Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave W., Waterloo, ON, N2L 3G1, Canada.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Glawdel
authors.affiliation: Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave W., Waterloo, ON, N2L 3G1, Canada.
authors.forename: Carolyn L
authors.initials: CL
authors.lastname: Ren
authors.affiliation: Department of Civil and Environmental Engineering, University of Waterloo, 200 University Ave W., Waterloo, ON, N2L 3G1, Canada.
authors.forename: Monica B
authors.initials: MB
authors.lastname: Emelko