[SY-H3] Symposium H-3

[SY-H3] Mechanical behavior of hydrated polymers at nanoscale: from elasticity to rupture.

^○William Goncalves¹, Takuya Mabuchi², Takashi Tokumasu¹ (1.Institute of Fluid Science, Tohoku University, Sendai, Miyagi 980-8577, Japan, 2.Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan)

Because of their emissions free of carbon dioxyde, polymer electrolyte fuel cells (PEFCs) are of great interest for energy production respectful of the environment. The transport of charges between the electrodes of the fuel cell is insured by a hydrated polymer membrane such as perfluorosulfonic acid (PFSA) membrane. The durability of the fuel cell is still limited by the chemical and mechanical degradation of the polymer membrane after cycles of utilization. This work focuses on the study of the mechanical behavior of PFSA membrane at nanoscale. The understanding of the relation between structure and mechanical properties is the key point to improve the resistance of the membrane against mechanical degradation.

Molecular Dynamics (MD) simulations are performed using a Coarse-Grained model to generate samples of PFSA membranes. The results obtained from structural characterization are compared with data from previous atomistic models and experiments. After validation of the nanostructures, mechanical tests are performed on the hydrated polymer membrane. With an increasing level of hydration, the results for elastic properties are in good agreement with experimental values and a similar trend as experiments is observed for early plastic behavior. The computation of the local mechanical properties of the samples allows to discuss the void nucleation and the influence of water content on the rupture behavior.