Dielectric Properties of Polyelectrolyte Solutions

Dielectric properties of polyelectrolyte solutions have been studied experi­ mentally for more than thirty years, but progress in understanding these properties has been rather slow. A particularly unfavorable combination of experimental difficulties and unsettled theoretical problems has noticeably influenced both the extent of the work devoted to this subject and the pace in which explanation and prediction proceeds in this field. The latter is not surprising in view of the difficulties encountered in dielectric theory in general (see e.g. Refs. 1 , 2) and taking into account the additional problems arising through the presence of free charges in the solution. Moreover, in the complementary field of the dielectric properties of ordinary electrolyte solutions, the situation is hardly better, and even there many problems remain unsolved in spite of recent progress (3). In recent years new theoretical work directly or indirectly related to the dielectric properties of aqueous polyelectrolyte solutions has appeared (see the section on Theory), focusing attention again on the rather un­ satisfactory state of affairs in this field. Hence, the appearance of this review seems justified and we hope it will stimulate further investigations, theoretical as well as experimental, in which new possibilities available through developments in other areas might be exploited. A further justification is that in recent times, only a few review articles of limited extent in this field have appeared (4-7). We shall limit this survey to aqueous solutions of true polyelectrolytes,