title: Electrostatically tuned interactions in silica microsphere-polystyrene nanoparticle mixtures.
abstract: We explore the generality of nanoparticle haloing as a novel colloidal stabilization mechanism in binary mixtures of silica microspheres and polystyrene nanoparticles. By selectively tuning their electrostatic interactions, both the initial microsphere stability and the role of nanoparticle additions are varied. Adsorption isotherm and zeta potential measurements indicate that highly charged nanoparticles exhibit a weak (haloing) association with negligibly charged microspheres, whereas they either strongly adsorb onto oppositely charged or are repelled by like-charged microsphere surfaces, respectively. Bulk sedimentation and confocal scanning fluorescence microscopy reveal that important differences in system stability emerge depending on whether the added nanoparticles serve as haloing, bridging, or depletant species.
authors.affiliation: Frederick Seitz Materials Research Laboratory, Materials Science and Engineering Department, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: Angel T
authors.initials: AT
authors.lastname: Chan
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Lewis
mesh_terms: D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011137:Polystyrenes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D055672:Static Electricity; D013499:Surface Properties
chemical_list: D011137:Polystyrenes; D012822:Silicon Dioxide