Polymer gel electrolytes containing acetic acid and different (mono-, di- and tri-) chloroacetic acids with polymethylmethacrylate (PMMA) and polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP) as the gelling polymer has been studied. The conductivity depends upon the dissociation constant of the acid used and some undissociated acid is also present in these electrolytes containing weak acids. The addition of polymer (PMMA, PVdF-HFP) has been found to result in an increase in conductivity and sigma (gel)>sigma (liquid) has been observed along with an increase in the viscosity of the electrolytes. FTIR results show that the polymer contributes to the conductivity modification by enhancing the dissociation of undissociated acid/ion aggregates present in these electrolytes. (C) 2004 Published by Elsevier B.V.