A quaternary 1,4-diazabicyclo-[2.2.2]-octane polysulfone (QDPSU) alkaline anion-exchange fuel-cell membrane was synthesized. Nanoindentation and uniaxial tension methods were used to test the mechanical properties of this membrane in both the thickness direction and length direction at 26 C and 40% relative humidity. We found that the QDPSU membrane exhibited remarkable viscoelastic properties with significant loading rate-dependent behavior and time-dependent behavior (creep-relaxation). The value of compression creep rates and compression relaxation rates of the QDPSU membrane were measured to be about 0.2 by a spherical indenter and changed very little with different holding loads. Compared with Nafion, a most widely used fuel-cell membrane, the QDPSU alkaline anion-exchange membrane showed a better creep resistance. During the nanoindentation fatigue test, the variation of depths with the indentation cycles were divided into a rising primary region, a steady-state secondary region, and a continuous declining region. This was different from the uniaxial tension fatigue test. The cross-scale and cross-direction mechanical study from this work will help provide new evidence for bridging the gap between nanoindentation and uniaxial tensile testing.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.