CONFORMATIONS OF FREELY JOINTED POLYAMPHOLYTES IN EXTERNAL FIELDS

We extend our previous treatment [J. Chem. Phys. 103, 5070 (1995)] of polyampholytes (PAs, polymers with positively and negatively charged m onomers) in an external field E, by modeling the PAs through freely jo inted chains. Former works, based on Rouse-type models are linear, and hence are limited to sufficiently small values of E. The freely joint ed chain model allows to consider the PAs conformations for E arbitrar y. We calculate the PAs end-to-end distance for several charge distrib utions along the chain, which may be either ordered or random. For sma ll E we recover previous results; large E-values lead to a crossover t o stretched chain configurations, which depend crucially on the distri bution of charges along the chain. (C) 1996 American Institute of Phys ics.