纳米级Nafion薄膜的三维精细结构,ACS Applied Polymer Materials

当前位置： X-MOL 学术 › ACS Appl. Polym. Mater. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

纳米级Nafion薄膜的三维精细结构
ACS Applied Polymer Materials ( IF 4.4 ) Pub Date : 2021-01-28 , DOI: 10.1021/acsapm.0c01318
A. Peltonen ₁ , J. Etula ₂ , J. Seitsonen ₃ , P. Engelhardt ₃ , T. Laurila _{2,

4}

Affiliation

Nafion是一种广泛使用的聚合物膜，其应用范围广泛，从先进的能源解决方案到生物分子传感。尽管多年来进行了深入的研究以揭示和理解Nafion的精细结构，但其结构特征（尤其是纳米级薄膜）并没有明确的已知。在本文中，我们使用室温扫描透射电子显微镜（STEM）断层扫描，辅以低温下掠射入射小角X射线散射（GISAXS）和TEM，揭示了未退火的薄（10–100 nm）Nafion的精细结构。电影。从详细的三维重建获得的结果表明：（i）聚合物的疏水和亲水部分的相分数在一定程度上取决于厚度，从0.65 / 0.35变为约0.7 / 0。从100到10 nm厚的薄膜移动时为3 （ii）在所有膜中，通道直径均显示出3至6 nm的值，而与膜的厚度无关；（iii）薄膜内部亲水通道之间的平均距离分布集中在12 nm（在10 nm薄膜中），15 nm（在30 nm薄膜中）和7 nm（在100 nm薄膜中）附近；（iv）在最厚的膜中，亲水性通道表现出较高的互连性，并且某些通道似乎终止于Nafion膜内而不是穿过膜；（v）亲水性SiO会产生一些限制作用（iii）薄膜内部亲水通道之间的平均距离分布集中在12 nm（在10 nm薄膜中），15 nm（在30 nm薄膜中）和7 nm（在100 nm薄膜中）附近；（iv）在最厚的膜中，亲水性通道表现出较高的互连性，并且某些通道似乎终止于Nafion膜内而不是穿过膜；（v）亲水性SiO会产生一些限制作用（iii）薄膜内部亲水通道之间的平均距离分布集中在12 nm（在10 nm薄膜中），15 nm（在30 nm薄膜中）和7 nm（在100 nm薄膜中）附近；（iv）在最厚的膜中，亲水性通道表现出较高的互连性，并且某些通道似乎终止于Nafion膜内而不是穿过膜；（v）亲水性SiO会产生一些限制作用在10和30 nm厚的薄膜的情况下，图_2的表面显示为亲水通道在基板附近水平移动的趋势。此外，还证明了用于Nafion膜的稳定的室温STEM层析成像方法和保留干燥状态下Nafion的水合形态特征的样品制备方法。这些结果使人们对Nafion薄膜的精细结构有了更深入的了解，并为表征和理解其在不同应用中的性能提供了更好的手段。

"点击查看英文标题和摘要"

Three-Dimensional Fine Structure of Nanometer-Scale Nafion Thin Films

Nafion is a widely used polymer membrane in various applications ranging from advanced energy solutions to sensing of biomolecules. Despite the intensive research carried out over the years to reveal and understand the fine structure of Nafion, its structural features, especially as nanometer-scale films, are not unambiguously known. In this paper, we use room temperature scanning transmission electron microscopy (STEM) tomography complemented by glancing incidence small-angle X-ray scattering (GISAXS) and TEM at low temperatures to reveal the fine structure of thin (10–100 nm) unannealed Nafion films. The results from the detailed three-dimensional reconstructions obtained show that (i) the phase fractions of the hydrophobic and hydrophilic parts of the polymer are somewhat thickness-dependent, changing from 0.65/0.35 to about 0.7/0.3 when moving from 100 to 10 nm thick films; (ii) the channel diameters show a range of values from 3 to 6 nm in all the films independent of their thickness; (iii) the average distances between the hydrophilic channels inside the film have distributions centered around 12 nm (in 10 nm films), 15 nm (in 30 nm films), and 7 nm (in 100 nm films); (iv) in the thickest films, the hydrophilic channels exhibit higher interconnectivity and some of the channels appear to end within the Nafion film instead of going through the films; and (v) there are some confinement effects caused by the hydrophilic SiO₂ surface in the case of 10 and 30 nm thick films shown by the tendency of the hydrophilic channels to move horizontally near the substrate. Furthermore, a stable room temperature STEM tomography imaging method for Nafion films and a sample preparation method that preserves the characteristics of the hydrated morphology of Nafion in the dry state are demonstrated. These results provide a deeper understanding of the fine structure of Nafion thin films and provide a better means to characterize and understand their properties in different applications.

更新日期：2021-02-12

点击分享查看原文

点击收藏

公开下载

阅读更多本刊新发论文本刊介绍/投稿指南