Poly(methyl methacrylate)-based protonic gel electrolytes: a spectroscopic study

We present the first vibrational spectroscopic investigation of a novel non-aqeous proton conducting polymer gel electrolyte consisting of a PMMA matrix and a solvent mixture (ethylene carbonate (EC)/propylene carbonate (PC) or EC/PC/-N,Ndimethylformamide (DMF)) with a dissolved organic acid (benzoic or salicylic acid). The protonic conductivity of the gels is of the order similar to 10(-4)-10(-5) S/cm at room temperature. We show that the conductivity is proportional to the degree of dissociation of the acid, the latter determined from Raman spectroscopic data, and that the degree of dissociation depends on the properties of the solvent mixture. Finally, we comment on the relation between the proton conductivity and the solvent diffussion dynamics as studied by PCS. (C) 2000 Elsevier Science Ltd. All rights reserved.