THEORY OF DILUTE POLYAMPHOLYTE SOLUTIONS IN EXTERNAL ELECTRICAL FIELDS

In this work we display recent findings on the conformations and dynam ics of polyampholytes (PAs; polymers with positively and negatively ch arged monomers) in external electrical fields. We consider the case in which the interactions between the charges are less important (weak c oupling limit) and also the case in which they are fundamental (strong coupling case). In the weak coupling limit we present analytical resu lts for Gaussian and also for freely-jointed chains. Through scaling a rguments we discuss the influence of the excluded volume on the PA's c onfigurations. Furthermore we evaluate the dynamics of PAs in the fram ework of the Rouse and of the Zimm models. In the strong-coupling regi me PAs with vanishing total charge form spherical globules. Using a dr oplet analogy we examine the response of PAs to external fields and sh ow the onset of an instability reminiscent of a first-order phase tran sition.