title: Small-angle neutron scattering on a core-shell colloidal system: a contrast-variation study.
abstract: Small-angle neutron scattering (SANS) measurements are reported on a sterically stabilized, core-shell colloidal system using contrast variation. Aqueous dispersions of polystyrene particles bearing grafted poly(ethylene glycol) (PEG) have been studied over a large range of particle concentrations and two different solvent conditions for the PEG polymer. SANS data are analyzed quantitatively by modeling the particles as core-shell colloids. In a good solvent and under particle contrast conditions, an effective hard-sphere interaction captures excluded-volume interactions up to high concentrations. Contrast variation, through isotopic substitution of both the core and solvent, expedite a detailed study of the PEG layer, both in the dilute limit and as a function of the particle concentration. Upon diminishing the solvent quality, subtle changes in the PEG layer translate into attractions among particles of moderate magnitude.
authors.affiliation: Department of Chemistry, Göteborg University, Sweden. malinz@chem.gu.se
authors.forename: M
authors.initials: M
authors.lastname: Zackrisson
authors.forename: A
authors.initials: A
authors.lastname: Stradner
authors.forename: P
authors.initials: P
authors.lastname: Schurtenberger
authors.forename: J
authors.initials: J
authors.lastname: Bergenholtz