ELECTROSTATIC INTERACTIONS OF RODLIKE POLYELECTROLYTES WITH REPULSIVE, CHARGED SURFACES

The interactions of an isolated, rodlike polyelectrolyte with nearby surfaces of like charge are examined by using simple descriptions of both the polyelectrolyte and the free energy of interaction: the rodlike polymer is treated as a line charge and the interaction energy is handled in the Debye-Huckel approximation. A combination of electrostatic and entropic effects is predicted to produce both segmental depletion and chain orientation. The depletion predictions have been incorporated into a molecular model for polyelectrolyte separation in size exclusion chromatography columns containing a stationary phase with surface charge. In the region close to a flat wall, long-range repulsive interactions create preferential alignment of rod segments perpendicular to the plane of the wall; without these interactions, parallel alignment is favored. © 1990, American Chemical Society. All rights reserved.