Abstract
The synthesis, thermal, electrochemical and proton-conducting properties of copolymers based on 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and 1-vinyl-1,2,4-triazole (VTri) were investigated. The copolymers were synthesized by free-radical copolymerization of the corresponding monomers at several monomer feed ratios to obtain poly(VTri-co-AMPS) copolymer electrolytes. The final structures of the copolymers were confirmed by FT-IR and H-1 NMR methods. The composition of the copolymers was determined by elemental analysis. TGA indicates that the copolymers are thermally stable up to approximately 250 degrees C. The copolymer samples have higher glass transition temperatures as shown by DSC. Cyclic voltammetry results illustrated that the electrochemical stability domain extends over 3 V. Charge transport relaxation times were derived from complex electrical modulus formalism (M*). The temperature dependence of conductivity relaxation times showed that the proton conductivity occurs by hopping mechanism via structure diffusion. In the absence of humidity, the copolymer electrolyte, poly(VTri-co-AMPS) (S2) showed proton conductivity of 2 x 10(-3)S/cm at 130 degrees C, which is far higher than in imidazole based copolymers. (c) 2010 Elsevier B.V. All rights reserved.