Continuum theories of structured dielectrics

Aequous dielectrics are ubiquitous in soft- and bio-nano matter systems. The theoretical description of such systems in terms of continuum (`macroscopic') theory remains a serious challenge. In this perspective we first review the existing continuum phenomenological approaches that have been developed in the past decades. In order to describe a path to advance continuum theory beyond these approaches we then take recourse to the Onsager-Dupuis theory of the dielectric behaviour of ice, which, for the case of a solid dielectric, exemplified important conceptual issues we deem relevant for the development of a more fundamental continuum theory of liquid dielectrics. Subsequently, we discuss our recently proposed continuum field theory of structured dielectrics, which provides a generalized approach to the dielectric behavior of such systems.