title: Interaction of silica nanoparticles with a flat silica surface through neutron reflectometry.
abstract: Neutron reflectometry (NR) was employed to study the interaction of nanosized silica particles with a flat silica surface in aqueous solutions. Unlike other experimental tools that are used to study surface interactions, NR can provide information on the particle density profile in the solution near the interface. Two types of silica particles (25 and 100 nm) were suspended in aqueous solutions of varying ionic strength. Theoretical calculations of the surface interaction potential between a particle and a flat silica surface using the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory were compared to the experimental data. The theory predicts that the potential energy is highly dependent on the ionic strength. In high ionic strength solutions, NR reveals a high concentration of particles near the flat silica surface. Under the same conditions, theoretical calculations show an attractive force between a particle and a flat surface. For low ionic strength solutions, the particle concentration near the surface obtained from NR is the same as the bulk concentration, while depletion of particles near the surface is expected because of the repulsion predicted by the DLVO theory.
authors.affiliation: Georgia Institute of Technology, Atlanta, Georgia 30332-0373, United States.
authors.forename: Eunhyea
authors.initials: E
authors.lastname: Chung
authors.forename: Sotira
authors.initials: S
authors.lastname: Yiacoumi
authors.forename: Candice
authors.initials: C
authors.lastname: Halbert
authors.forename: John
authors.initials: J
authors.lastname: Ankner
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Changwoo
authors.initials: C
authors.lastname: Kim
authors.forename: Costas
authors.initials: C
authors.lastname: Tsouris
mesh_terms: D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009502:Neutrons; D009994:Osmolar Concentration; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D012822:Silicon Dioxide