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Polyelectrolyte electrophoresis: Effects of molecular weight and molecular architecture

Cynthia F Welch, University of Massachusetts Amherst


The work described in this dissertation reveals the potential of electrophoretic techniques for the characterization and better understanding of polyelectrolyte solutions. The dependence of electrophoretic mobility μ on parameters such as solution ionic strength, polymer charge density, molecular weight, and chain architecture are explored. For oligomers, the free solution electrophoretic mobility μ0 exhibits an unambiguous maximum with respect to molecular weight M; lowering solution ionic strength I accentuates this poorly understood phenomenon. Though the dependence of μ0 on M disappears at higher M, electrophoretic migration through dilute neutral polymer solutions will give M-dependent μ-distributions for high M polyelectrolytes. Until now, this capillary electrophoresis technique was limited to polyanion analysis; a method of overcoming the technological challenges of analyzing polycations with this technique is presented here. The new ability to analyze polycations via capillary electrophoresis opens the door to many new investigations into polyelectrolyte solution behavior. This capability is demonstrated by a comprehensive study of protonated dendrimers: μ 0 is investigated as a function of I, dendrimer charge, and dendrimer radius. The results match predictions of the standard electrokinetic model for a dielectric sphere, revealing that the relaxation effect dominates the electrophoretic behavior of highly charged dendrimers.

Subject Area


Recommended Citation

Welch, Cynthia F, "Polyelectrolyte electrophoresis: Effects of molecular weight and molecular architecture" (2002). Doctoral Dissertations Available from Proquest. AAI3056287.