title: Diverging electrophoretic and dynamic mobility of model silica colloids at low ionic strength in ethanol.
abstract: Electroacoustics and laser Doppler electrophoresis were employed to measure the mobility of surface-modified silica colloids in ethanol as a function of the ionic strength. Sufficiently low volume fractions were chosen to exclude effects of interparticle interactions. At high ionic strength, the electrophoretic mobility μ(e) is equal to the (electroacoustic) dynamic mobility μ(d) at 3.3 MHz. However, the ratio μ(d)/μ(e) increases significantly to ∼5 at low ionic strength. This increase may be related to the porous outer layer of the surface-modified silica spheres.
authors.affiliation: Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. Electronic address: r.j.kortschot@uu.nl.
authors.forename: R J
authors.initials: RJ
authors.lastname: Kortschot
authors.affiliation: Laboratory for Physical Chemistry and Colloid Science of Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands. Electronic address: hans.lyklema@wur.nl.
authors.forename: J
authors.initials: J
authors.lastname: Lyklema
authors.affiliation: Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. Electronic address: a.p.philipse@uu.nl.
authors.forename: A P
authors.initials: AP
authors.lastname: Philipse
authors.affiliation: Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. Electronic address: b.h.erne@uu.nl.
authors.forename: B H
authors.initials: BH
authors.lastname: Erné
keywords: Colloid vibration current; Colloidal charge; Debye length; Electrical double layer; Electroacoustics; Laser Doppler electrophoresis; Maxwell–Wagner relaxation; Zeta potential