Instabilities of polyampholytes in external electrical fields

Abstract

We consider the behavior of polyampholytes (PAs; heteropolymers carrying quenched positive and negative charges along the backbone) in external electrical fields. Whereas our previous treatments were devoted to the regime of a weak coupling of the charges, we consider here the regime where the electrostatic interactions between the charged monomers play the dominant role. Starting from a fluid drop picture we estimate the critical value of the external field that induces a breakup of the structure. As we proceed to show by scaling arguments, in strong fields the PA stretches out to a highly extended form, for which only a small fraction of the material is still organized in mesoscopic condensates along the rodlike configuration.