The synthesis and proton-conducting properties of the copolymers based on 1-vinyl-1,2,4-triazole and 2-acrylamido-2-methyl-1-propanesulfonic acid

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 1H NMR methods. The composition of the copolymers was determined by elemental analysis. TGA indicates that the copolymers are thermally stable up to approximately 250 °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 × 10 − 3 S/cm at 130 °C, which is far higher than in imidazole based copolymers.