Density-Functional Theories for Polyelectrolyte Systems

Polymer density-functional theories (PDFTs) have distinct advantages in the study of polyelectrolyte (PE) systems over experiments and molecular simulations. Here we give an introductory review of some PDFTs recently developed for PE systems. We start with a general formalism of PDFTs and its relation to the widely used polymer self-consistent field theory (SCFT), then explain the various correlations that are neglected in SCFT but can be accounted for in PDFTs, including those due to the excluded-volume interaction and chain connectivity of uncharged polymers, the electrostatic correlations of small ions, and the chain correlations in PEs. We also list some applications of PDFTs for PE systems, and finally give some perspectives on future work. We hope that our review can attract more researchers to apply and further develop PDFTs as a promising class of theoretical and computational tools.