Pham Tuyet Anh, Koo Seunghoe, Park Hyunseok, Luong Quang Thien, Kwon Oh Joong, Jang Segeun, Kim Sang Moon, Kim Kyeongtae
Department of Mechanical Engineering, Incheon National University, Incheon 22012, Korea.
Department of Energy and Chemical Engineering, Incheon National University, Incheon 22012, Korea.
Polymers (Basel). 2021 Nov 20;13(22):4018. doi: 10.3390/polym13224018.
The Nafion electrolyte membrane, which provides a proton pathway, is an essential element in fuel cell systems. Thermal treatment without additional additives is widely used to modify the mechanical properties of the membrane, to construct reliable and durable electrolyte membranes in the fuel cell. We measured the microscopic mechanical properties of thermally annealed membranes using atomic force microscopy with the two-point method. Furthermore, the macroscopic property was investigated through tensile tests. The microscopic modulus exceeded the macroscopic modulus over all annealing temperature ranges. Additionally, the measured microscopic modulus increased rapidly near 150 °C and was saturated over that temperature, whereas the macroscopic modulus continuously increased until 250 °C. This mismatched micro/macroscopic reinforcement trend indicates that the internal reinforcement of the clusters is induced first until 150 °C. In contrast, the reinforcement among the clusters, which requires more thermal energy, probably progresses even at a temperature of 250 °C. The results showed that the annealing process is effective for the surface smoothing and leveling of the Nafion membrane until 200 °C.
提供质子传导路径的全氟磺酸（Nafion）电解质膜是燃料电池系统中的关键部件。在不添加额外添加剂的情况下进行热处理，被广泛用于改善膜的机械性能，以构建燃料电池中可靠且耐用的电解质膜。我们采用两点法通过原子力显微镜测量了热退火膜的微观力学性能。此外，还通过拉伸试验研究了宏观性能。在所有退火温度范围内，微观模量均超过宏观模量。另外，测得的微观模量在150℃附近迅速增加，并在该温度以上达到饱和，而宏观模量则持续增加直至250℃。这种微观/宏观增强趋势的不匹配表明，在150℃之前首先诱导了簇的内部增强。相比之下，需要更多热能的簇间增强可能甚至在250℃的温度下仍在进行。结果表明，直到200℃，退火过程对于Nafion膜的表面平滑和整平都是有效的。
