This paper reports, for the first time, the effect of configurational free volume (i.e., triptycene units) on condensable vapor transport in polymers. Alcohol and water vapor solubility and diffusivity isotherms at 25 °C in a triptycene-containing polybenzoxazole (TPBO) exhibiting configurational free volume are presented as a function of vapor activity, discussed, and used to develop fundamental structure–property correlations. This study provides evidence that while in conventional glassy polymers alcohol diffusion is size-controlled and sorption is enthalpy-controlled, which may create a trade-off between sorption- and diffusion-selectivity, alcohol sorption and diffusion in TPBO are both size-controlled, which makes it potentially easier to simultaneously tune sorption- and diffusion-selectivity to achieve highly selective separations. To put these results in a broad perspective, alcohol sorption and diffusion properties of TPBO were compared with those of conventional glassy polymers exhibiting conformational free volume, such as PIM-1, Teflon AF2400, polynorbornene, polysulfone, as well as rubbery PDMS. Finally, new exciting opportunities to exploit these unique TPBO’s features for large scale molecular separations are discussed.

中文翻译：

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显示构型自由体积的玻璃态聚苯并恶唑中尺寸筛分驱动的蒸汽吸附和扩散的证据

本文首次报道了构型自由体积（即三苯乙烯单元）对聚合物中可冷凝蒸汽传输的影响。在 25 °C 下，在含三苯并恶唑 (TPBO) 中的醇和水蒸气溶解度和扩散等温线表现出自由构型的自由体积，作为蒸气活性的函数进行了讨论，并用于开发基本结构 - 性质相关性。这项研究提供的证据表明，虽然在传统的玻璃状聚合物中，醇的扩散是受尺寸控制的，而吸附是受焓控制的，这可能会在吸附选择性和扩散选择性之间进行权衡，但 TPBO 中的醇吸附和扩散都受尺寸控制，这使得同时调整吸附和扩散选择性以实现高选择性分离可能更容易。为了将这些结果放在更广阔的视野中，将 TPBO 的醇吸附和扩散特性与具有构象自由体积的传统玻璃聚合物（如 PIM-1、Teflon AF2400、聚降冰片烯、聚砜以及橡胶状 PDMS）进行了比较。最后，讨论了利用这些独特的 TPBO 功能进行大规模分子分离的令人兴奋的新机会。