INSTABILITIES OF POLYAMPHOLYTES IN EXTERNAL ELECTRICAL FIELDS

We consider the behavior of polyampholytes (PAs; heleropolymers carryi ng quenched positive and negative charges along the backbone) in exter nal electrical fields. Whereas our previous treatments were devoted to the regime of a weak coupling of the charges, we consider here the re gime where the electrostatic interactions between the charged monomers play the dominant role. Starting from a fluid drop picture we estimat e the critical value of the external field that induces a breakup of t he structure. As we proceed to show by scaling arguments, in strong fi elds die PA stretches out to a highly extended form, for which only a small fraction of the material is still organized in mesoscopic conden sates along tile rodlike configuration. (C) 1996 American Institute of Physics.