title: Preparation and properties of starch-based colloidal microgels.
abstract: Novel starch microgels were prepared by emulsion cross-linking and characterized with respect to shape, volume, and mass density. Starch microgels appear to be negatively charged ( approximately -50 mV), with a particle size varying as a function of the type of cross-linker (ca. 0.25-10 microm). Environmental scanning electron microscopy observations show a dependence of the particle swelling on the cross-linking density. Viscosimetry reveals that starch microgels behave as charged polymers, where the reduced viscosity increases with dilution (anomalous viscosity behavior) for sufficiently low kappaalpha (ca. kappaalpha <3), the ratio of the particle radius (a), and the Debye length (kappa(-1)). Analogous results are obtained for reference-charged rigid silica spheres, which approach the hard sphere limit for increasing ionic strengths. The shape of the microgels appears to play a minor role in the anomalous viscosity behavior, which is more likely dominated by electrostatic effects.
authors.affiliation: Agrotechnological Research Institute (ATO), P.O. Box 17, 6700 AA Wageningen, The Netherlands.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Dziechciarek
authors.forename: Jeroen J G
authors.initials: JJ
authors.lastname: van Soest
authors.forename: Albert P
authors.initials: AP
authors.lastname: Philipse