Correlating Gas Permeability and Young's Modulus during the Physical Aging of Polymers of Intrinsic Microporosity Using Atomic Force Microscopy
Correlating Gas Permeability and Young's Modulus during the Physical Aging of Polymers of Intrinsic Microporosity Using Atomic Force Microscopy
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DOI：
10.1021/acs.iecr.9b04881
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发表时间：
2020-03-25
影响因子：
4.2
通讯作者：
Jansen, Johannes C.
中科院分区：
文献类型：
--
作者：
Longo, Mariagiulia;De Santo, Maria Penelope;Jansen, Johannes C.
在物理老化过程中，传输性能和杨氏模量之间的关系的固有微孔（PIM）的聚合物膜的研究，使用纯气体渗透性和原子力显微镜（AFM）的力谱模式。原型PIM-1与文献中通过其他技术获得的值测量的杨氏模量的极好的一致性，证实了AFM力谱用于机械性能的快速和方便的评估的适用性。从不同的聚合物，包括PIM-1和五个超渗透苯并三蝶烯为基础的PIM的结果提供了直接的证据，尺寸选择性是强烈相关的杨氏模量。此外，对一种代表性PIM（PIM-DTFM-BTrip）的薄膜样品进行正常物理老化和真空热调节加速老化，以进行比较。加速老化导致渗透性降低和杨氏模量增加与正常老化相似，然而，显著差异表明热诱导加速老化发生在整个聚合物膜的主体中，而正常老化主要发生在膜的表面。对于所有PIM，老化后的膜刚度增加导致气体尺寸选择性增加。
The relationship, during physical aging, between the transport properties and Young's modulus for films of polymers of intrinsic microporosity (PIM) was investigated using pure gas permeability and atomic force microscopy (AFM) in force spectroscopy mode. Excellent agreement of Young's modulus measured for the archetypal PIM-1 with values obtained by other techniques in the literature, confirms the suitability of AFM force spectroscopy for the rapid and convenient assessment of mechanical properties. Results from different polymers including PIM-1 and five ultrapermeable benzotriptycene-based PIMs provide direct evidence that size selectivity is strongly correlated to Young's modulus. In addition, film samples of one representative PIM (PIM-DTFM-BTrip) were subjected to both normal physical aging and to accelerated aging by thermal conditioning under vacuum for comparison. Accelerated aging resulted in a similar decrease in permeability and increase in Young's modulus as normal aging, however, significant differences suggest that thermally induced accelerated aging occurs throughout the bulk of the polymer film whereas normal aging occurs predominantly at the surface of the film. For all PIMs, the increased in film rigidity upon aging led to an increase in gas size selectivity.