Abstract
By molecular dynamics simulations, we investigated the transport of charged polymers in applied electric fields in confining environments, which were straight cylinders of uniform or non-uniform diameter. In the simulations, the solvent was modeled explicitly and, also, the counterions and coions of added salt. The electrophoretic velocities of charged chains in relation to electrolyte friction, hydrodynamic effects due to the solvent, and surface friction were calculated. We found that the velocities were higher if counterions were moved away from the polymeric domain, which led to a decrease in hydrodynamic friction. The topology of the surface played a key role in retarding the motion of the polyelectrolyte and, even more so, in the presence of transverse electric fields. The present study showed that a possible way of improving separation resolution is by controlling the motion of counterions or electrolyte friction effects.
Highlights
Experiments and computer simulations show that charged chains in free solution under an external applied electric field migrate with the same electrophoretic velocity independent of the chain size [1]
We carried out molecular dynamics simulations of the electrophoresis of charged chains in cylinder geometries with smooth walls and undulations
The electrolyte friction was found to be generally lower than in longitudinal fields only, because counterions were partially removed from the vicinity of the polyion, and the counter electroosmotic flow was reduced
Summary
Experiments and computer simulations show that charged chains in free solution under an external applied electric field migrate with the same electrophoretic velocity independent of the chain size [1](except for very small rod-like polyions). Experiments and computer simulations show that charged chains in free solution under an external applied electric field migrate with the same electrophoretic velocity independent of the chain size [1]. To further derive an analytical expression for the electrophoretic velocity, the charge density within the polymer domain must be calculated and, Materials 2013, 6 the hydrodynamic friction due to the solvent [2]. In the limit of a completely permeable coil to the solvent molecules, which flow unperturbed through the polymer coil, the fluid resistance is proportional to the degree of polymerization, or chain length. The fluid resistance is that of Stokes’ law, which means that friction is proportional to chain size [3] and scales linearly with Rs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
