Abstract
The design of novel proton exchange membranes with high conductivity and better dimensional stability has become increasingly important due to the need for applications in different devices. The present work shows the acid-doped and crosslinked polyacrylamide (PAM) networks including flexible spaces. To this end PAM was modified with 1,4-butanediol diglycidyl ether (BG) to form PAM35BG and PAM50BG networks, which would afford more space for protonated solvents. The reaction of PAM with BG was monitored by FTIR and C-13 CP-MAS NMR. The polymer electrolytes were produced by acid doping at several stoichiometric ratios with respect to the monomer repeat unit of a host polymer. The resulting materials exhibited better thermal, chemical, and electrochemical stabilities and had distinct T-g values. Additionally, the pores of the PAM-BG materials were filled with H3PO4 to get PAM35BG0.5H(3)PO(4) and PAM50BG1.0H3PO4. The doping enhanced the proton conductivities of the membranes as high as 0.003 S/cm at 120 degrees C under an anhydrous atmosphere. The proton diffusion mechanism and the dielectric relaxation were further examined using the complex modulus formalism, M*.