RESUMEN
The behavior of ionic current rectification (ICR) in a conical nanopore with its surface modified by pH-tunable polyelectrolyte (PE) brushes connecting two large reservoirs subject to an applied electric field and a salt gradient is investigated. Parameters including the solution pH, types of ionic species, strength of applied salt gradient, and applied potential bias are examined for their influences on the ionic current and rectification factor, and the mechanisms involved are investigated comprehensively. The ICR behavior depends highly on the charged conditions of the PE layer, the level of pH, the geometry of nanopore, and the thickness of the double layer. In particular, the distribution of ionic species and the local electric field near the nanopore openings play a key role, yielding profound and interesting results that are informative to device design as well as experimental data interpretation.
RESUMEN
The influence of temperature on the electrophoresis of a spherical, pH-regulated polyelectrolyte (PE) particle having both acidic and basic functional groups in an aqueous salt solution containing multiple ionic species is investigated theoretically. The type of particle considered simulates entities including proteins, biomolecules, and synthetic polymers. The applicability of the model proposed is verified by the experimental data of succinoglycan nanoparticles reported in the literature. Taking a glycin PE as an example, the variations of its mobility with the temperature, bulk salt concentration, and pH are examined through numerical simulation. Empirical relationships that correlate the mobility with these factors are obtained for temperature, bulk salt concentration, and pH ranging from 293 to 308 K, 10(-4) to 10(-2) M, and 2-10.5, respectively. Several interesting and important results for the PE mobility are observed. These results provide not only valuable information for interpreting experimental data but also for designing electrophoresis devices where temperature can play a role.