“…The dynamics of polyelectrolyte gels has also received a great deal of attention, and systems of evolution equations have been proposed by many authors [18,16,19,31,34,49,48,52,32,9,1,23]. A standard approach, which we adopt in this paper, is to treat polyelectrolyte gels as a two phase medium of polymer network and fluid, with the ions being treated as solute species dissolved in the fluid.…”