title: Anomalous mobility of highly charged particles in pores.
abstract: Single micropores in resistive-pulse technique were used to understand a complex dependence of particle mobility on its surface charge density. We show that the mobility of highly charged carboxylated particles decreases with the increase of the solution pH due to an interplay of three effects: (i) ion condensation, (ii) formation of an asymmetric electrical double layer around the particle, and (iii) electroosmotic flow induced by the charges on the pore walls and the particle surfaces. The results are important for applying resistive-pulse technique to determine surface charge density and zeta potential of the particles. The experiments also indicate the presence of condensed ions, which contribute to the measured current if a sufficiently high electric field is applied across the pore.
authors.affiliation: ‡School of Mechanical Engineering and Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, Southeast University, Nanjing 211189, China.
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Qiu
authors.forename: Crystal
authors.initials: C
authors.lastname: Yang
authors.forename: Preston
authors.initials: P
authors.lastname: Hinkle
authors.affiliation: ∥Oak Ridge National Laboratory, Bethel Valley Road, Oak Ridge, Tennessee 37831, United States.
authors.forename: Ivan V
authors.initials: IV
authors.lastname: Vlassiouk
authors.forename: Zuzanna S
authors.initials: ZS
authors.lastname: Siwy